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nature publishing group ORIGINAL CONTRIBUTIONS

2012 by the American College of Gastroenterology TheAmerican Journal ofGASTROENTEROLOGY

see related editorial on page x

INTRODUCTIONTe chronic inammatory bowel diseases (IBD) encompass the

major types Crohns disease (CD) and ulcerative colitis (UC)

in addition to IBD unclassied (IBD-U). Up to 25% o the IBDpatients present in childhood or adolescence, with epidemiologi-

cal and natural history studies demonstrating that the incidence

o pediatric-onset IBD (PIBD) is rising, especially with regard to

early-onset CD (1,2).

Te initial investigation o children with suspected bowel inam-

mation includes both serum and ecal biomarkers to identiy

those patients warranting endoscopic evaluation (3). One marker,

ecal calprotectin (FC), is a calcium-binding protein ound in

neutrophilic granulocytes. FC has previously been shown to be

markedly raised in children and adults with IBD (4,5), with itsstability allowing the convenient collection o this non-invasive

marker in both inpatient and outpatient settings (6).

A recent meta-analysis evaluating the role o FC during the ini-

tial investigation o suspected IBD concluded that FC was a useul

screening tool to identiy patients requiring endoscopic assess-

ment (7), though the discriminative power to saely exclude IBD

The Diagnostic Accuracy of Fecal Calprotectin During

the Investigation of Suspected Pediatric InflammatoryBowel Disease

Paul Henderson, MBChB, MRPCH1,2, Aoife Casey, MBChB2, Sally J. Lawrence, MBChB, MRCPH2, Nicholas A. Kennedy, MBBS3,

Kathleen Kingstone, BSc, MSc, MPhil4, Pam Rogers, RGN, RSCN2, Peter M. Gillett, MBChB, FRCP, FRCPH2

and David C. Wilson, MD, FRCP, FRCPCH1,2

OBJECTIVES: Fecal calprotectin (FC) is elevated in patients with inflammatory bowel disease (IBD). Studies

evaluating FC during the initial investigation of children with suspected IBD have been limited,

especially with regard to their small patient groups. We aimed to evaluate the diagnostic accuracy

of FC in a large regional cohort of children undergoing full upper and lower endoscopy for suspected

IBD, comparing FC with six common blood parameters.

METHODS: Using a retrospective casecontrol design all FC measurements carried out between 2005 and 2010

in children < 18 years old were obtained. All IBD and non-IBD patients who had a FC measurement

available before full endoscopic evaluation for suspected bowel inflammation were examined. FC was

measured using the PhiCal Test. Multivariate analyzes and receiver operating characteristic curve

generation were used to derive significance.

RESULTS: A total of 190 patients (91 IBD and 99 non-IBD controls) met the inclusion criteria. Median FC at

diagnosis for the IBD group was 1,265g/g (interquartile range (IQR) 7342,024g/g), compared

with 65g/g (IQR 20235g/g) in controls (P< 0.001). FC levels did not vary significantly between

patients with Crohns disease, ulcerative colitis, and IBD unclassified and were not influenced by age

or disease location. FC was found to be far superior to commonly utilized blood parameters such as

C-reactive protein and white cell count (both P< 0.01), with an area under the curve of 0.93 (95%

confidence interval 0.890.97).

CONCLUSIONS: This study demonstrates that FC is an invaluable tool in determining those children who may require

endoscopy for suspected IBD, and elevated values should prompt further investigation.

SUPPLEMENTARY MATERIAL is linked to the online version of the paper at http://www.nature.com/ajg

Am J Gastroenterol2012; 107:941949; doi:10.1038/ajg.2012.33; published online 28 February 2012

1Child Life and Health, University of Edinburgh, Edinburgh, UK; 2Department of Pediatric Gastroenterology and Nutrition, Royal Hospital for Sick Children,

Edinburgh, UK; 3Gastrointestinal Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; 4Department of Biochemistry,

Western General Hospital, Edinburgh, UK. Correspondence: Paul Henderson, MBChB, MRPCH, Child Life and Health, University of Edinburgh, 20 Sylvan Place,

Edinburgh EH9 1UW, UK. E-mail: [email protected] 4 November 2011; accepted 17 January 2012


2/10TheAmerican Journal ofGASTROENTEROLOGY VOLUME 107 |JUNE 2012 www.amjgastro.com

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Henderson et al.

was signicantly better in adults than in children. However, the

included pediatric studies presented FC levels in only 226 IBD

patients; the median number o PIBD patients within the individ-

ual studies was only 31 (range, 1360), and not all were new diag-

noses. Tereore, larger studies including only new patient reerrals

are still required to ully assess the utility o this biomarker dur-

ing the initial assessment o suspected PIBD. Furthermore, the

comparative value o FC measurement with commonly used blood

parameters in pediatric patients has not yet been ully determined.

We thereore hypothesized that the diagnostic accuracy o FC

in suspected PIBD would be equivalent to endoscopy and supe-

rior to six commonly used blood parameters. We also aimed to

describe the differences in FC levels between IBD types (CD, UC,

and IBD-U) and non-IBD disease categories.

METHODS

Setting

Te pediatric gastroenterology department based at the RoyalHospital or Sick Children in Edinburgh provides a regional

service or a population o ~274, 000 children aged < 18 years in

SouthEast Scotland. Tis tertiary center unctions as a reerral

center or the three district general (community) hospitals with

pediatric services, in addition to two adult academic gastroen-

terology services in Edinburgh and all adult gastroenterology

departments within district general hospitals. Children present-

ing or reerred with suspected bowel inammation currently have

their primary investigations and initial ollow-up carried out at

this center by experienced pediatric gastroenterologists. Te bio-

chemistry department based at the Western General Hospital in

Edinburgh has routinely processed all FC samples in this regionsince October 2004, with access to all tests carried out in primary

care and all hospital-based services.

Fecal calprotectin measurements

All FC measurements carried out between January 1 2005 and

December 31 2010 in patients born afer January 1 1987 (to

ensure the inclusion o all patients potentially undergoing endos-

copy beore 18 years o age) in SouthEast Scotland were obtained

retrospectively rom the biochemistry department laboratory

records. Tese data included patient demographics, the unique

patient identier and unique specimen number, the location code

that species the sample origin (e.g., general practice, outpatient

department), and the sample date and FC concentration in g/go stool or all patients. Te data also specied i samples were

taken but were insuffi cient or processing. FC was measured by

the PhiCal est (Calpro AS, Lysaker, Norway) according to the

manuacturers instructions; the local assay analytical range is

202,500g/g. A normal FC value was taken to be < 50g/g stool

with the biochemistry laboratory routinely reporting FC results

as possible gastrointestinal (GI) inammation i between 51

and 100g/g, GI inammation i between 101 and 200g/g and

active GI inammation i >200g/g. In order to aid analysis o

FC levels, samples reported as < 20 and >2,500g/g were con-

verted to 20 and 2,500g/g, respectively.

IBD patients

All incident cases o PIBD diagnosed by standard clinical, his-

tological, and radiological ndings (8,9) since August 1997 have

been collected prospectively and recorded on a departmental

database using Microsof Access 2003 (Microsof, Redmond, WA).

From this database we identied patients who had a FC measured

as part o their initial diagnostic work-up during the 6-year period

o FC data rom 2005 to 2010 (hereafer reerred to as the IBD

group). Detailed phenotypic characteristics (10) or these patients

were also available through our Scotland-wide Medical Research

Council unded Paediatric Inammatory Bowel Disease Cohort

and reatment Study database.

Non-IBD (control) patients

Trough the departmental records containing the details o over

5,600 children reerred to pediatric gastroenterology services since

2001, a computerized search using the remaining FC sample list

determined those patients who had previously had contact with

the service. Tese hospital records and departmental endoscopylists were used to identiy all patients undergoing both upper and

lower endoscopy or the clinical suspicion o bowel inammation,

but where PIBD was subsequently excluded (hereafer reerred to

as the control group).

Exclusion criteria

Exclusion criteria or both the IBD and control groups were: (1)

insuffi cient stool sample provided; (2) aged < 1 year or >18 years

o age on the endoscopy date; (3) greater than a 6-month delay

between the FC sample and the endoscopy date; (4) FC sample

taken afer endoscopy; (5) any previously known, hospital diag-

nosed, GI disease; and (6) previous upper or lower GI endoscopy.

Blood parameters

Blood results (taken within 6 months o endoscopy and closest

to the date o the FC sample) were also obtained to compare the

diagnostic utility o FC with commonly used blood parameters,

namely: hemoglobin, platelet count, total white cell count, eryth-

rocyte sedimentation rate (ESR), serum albumin, and C-reactive

protein (CRP). Our regional pediatric biochemistryhematology

laboratory normal values by age and sex range are shown in Sup-

plementary Table 1. Within one reerral center, plasma viscosity

is routinely used as an alternative to ESR, thereore in six patients

within the control group plasma viscosity results were used as a

proxy or ESR with a reerence range o 1.501.72 mPa/s.

Data recording and statistics

Demographic inormation, details o endoscopic assessment,

FC and blood results, phenotypic inormation, prescribed medi-

cations at the time o the FC sample, and nal diagnosis were

recorded electronically using Microsof Access 2007 (Microsof).

Statistical analysis was perormed using R version 2.14.1 (R Foun-

dation or Statistical Computing, Vienna, Austria) and GraphPad

Prism version 4.03 (GraphPad Sofware, La Jolla, CA). Pearsons2,

Kruskal-Wallis, and MannWhitney U-tests were used where

appropriate; multivariate analysis was achieved using multiple


3/10 2012 by the American College of Gastroenterology TheAmerican Journal ofGASTROENTEROLOGY

Calprotectin During the Diagnosis of Pediatric IBD

logistic regression. Te R packages epiR (11) and pROC (12) were

used or urther analysis. Hemoglobin and total white cell counts

were standardized to the reerence range used or 1218 year

olds or the purpose o receiver operating characteristic (ROC)

curve generation. Youden index was calculated as sensitivity +

(specicity-1) (13). Statistical testing between receiver operating

characteristic curves was perormed using the DeLong (14) and

bootstrap (15) methods. Statistical signicance was taken to be a

two-tailed Pvalue o < 0.05.

Ethical approval

Ethical approval was sought but deemed unnecessary as this was

an anonymous, observational study o patients already under the

care o PIBD services and under the umbrella o the Paediatric-

onset IBD Scottish Audit.

RESULTS

Group characteristicsA ow diagram outlining the patient selection process is shown in

Figure 1. In total, 91 IBD patients and 99 non-IBD controls met

the inclusion criteria; the baseline characteristics o both groups

are outlined in Table 1. On univariate analysis the IBD group dem-

onstrated an older age at endoscopy, had a shorter time between

their FC sample and endoscopy and a higher terminal ileum (I)

intubation rate. However, only age at endoscopy and time between

FC sample and endoscopy remained signicant on multivari-

ate analysis, suggesting that differences in the I intubation rate

between the groups was a result o a higher age at endoscopy in

the IBD group (with endoscopy being less technically demanding

in older children). In addition, the I intubation rate was not sig-

nicantly different between those children with and without a FC

result available at endoscopy (P= 0.437).

Te IBD group consisted o 62 CD, 21 UC, and 8 IBD-U patients.

In IBD patients without a I biopsy obtained 30/34 (88%) had

small bowel imaging carried out within a median time o 46 days

(interquartile range (IQR) 2271 days) rom endoscopy. All but

one o the IBD group (99%) are currently recruited to our Paediatric

Inammatory Bowel Disease Cohort and reatment Study cohort;

the remaining patient died o a non-IBD-related illness beore

approach or possible consent.

Te diagnostic categories o the control group are shown in

Table 2and reect their denitive diagnosis afer ollow-up o at

least 12 months rom the date o endoscopy (median ollow-up 41

months (IQR 2453 months)). All children presented with one

or more symptoms suggestive o bowel inammation (Table 3);

37% had two recorded symptoms, and 23% had three or more. All

controls were ollowed-up to at least denitive diagnosis or to dis-

charge rom pediatric services. O those with no pathology identi-ed (n= 11), all have been discharged rom urther ollow-up on

no medications. o our knowledge none o the control group have

subsequently been diagnosed with PIBD by the end o December

2011. Unless they are now in adult services or have moved away

rom SouthEast Scotland, all potential PIBD diagnoses will have

been re-reerred to our service.

Children with IBD have a significantly elevated FC at

diagnosis compared with controls undergoing endoscopy

Te median FC at diagnosis or the IBD group was 1,265 g/g

(IQR 7342,024g/g, range 262,500g/g), which was higher

257 Insufficientsamples

1,117 Repeatresults

4,155 FC resultsidentified

Excluded

2,781 Individualpatients

845 Seen by tertiarypediatric GI services

ProspectivedepartmentalIBD database

220 non-IBD controls 113 IBD patients333 Underwent

endoscopy

0

42

18

12

14

0

2

12

0

8

9199 134

Exclusions

Complete upper and

lower endoscopy

>6 Month delaybetween FC sample

and endoscopy

FC sample taken afterendoscopy

Previous GI diagnosis

Previous endoscopy

Aged 18 years

Figure 1. Flow diagram showing the retrospective selection of study participants. FC, fecal calprotectin; GI, gastrointestinal; IBD, inflammatory bowel

disease.



44

PEDIAT

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Henderson et al.

(P< 0.001) than the control group with a median FC o 65 g/g(IQR 20235g/g, range 202,500g/g). Within the IBD group

only two patients had a FC < 50g/g recorded at initial presenta-

tion, an 11-year-old girl with colonic CD (Montreal L2 at diagno-

sis) who has required immunomodulators and adalimumab, and

a 4-year-old boy with pancolitic IBD-U who is currently stable

on maintenance mesalamine. Only one child in the control group

had a FC >2,500g/g, a 2-year-old girl with allergic enteropathy

who settled on dietary restrictions and who continues to have no

evidence o IBD during ongoing review.

Te diagnostic accuracy or FC at different cutoff levels is shown

in Table 4. Using the manuacturers normal cutoff o >50g/g

gives an excellent sensitivity (0.98), but a poor specicity (0.44)

or IBD. Tis specicity increases steadily with increasing FC lev-

els until the pay-off between sensitivity and specicity (calcu-

lated by the Youden index) plateaus at around 200300g/g. As

discussed above it can be seen that the IBD group had a higherrate o I biopsy, thereore to ensure that this was not conound-

ing the results regarding diagnostic accuracy, only those children

with an available I biopsy (n= 103) were analyzed separately. Tis

demonstrated that using a cutoff o >50g/g gave almost identical

results as when the entire cohort was evaluated (i.e., sensitivity 0.98

(95% condence interval (CI) 0.910.99); specicity 0.46 (95% CI

0.310.61); negative predictive value 0.95 (95% CI 0.770.99);

positive predictive value 0.69 (95% CI 0.580.79)). It is important

also to note that 34% (n= 63) o FC results returned afer the

endoscopic assessment was perormed, and that 14% (n= 27) o

FC results were not known in the preceding 2 weeks beore endo-

scopic assessment. Given our minimum 2 week delay to electiveGI endoscopy over the ull 6-year period, these 48% (n= 90) o

FC results could not have inuenced our decision making with

regard to perormance o endoscopy, nor the occurrence o I

intubation in 34% o patients. Furthermore, even or the 52% o

patients where FC results were known beore 2 weeks beore the

endoscopic assessment, none were cancelled afer conrmation o

procedure based on FC result, nor had procedures expedited based

on FC resultthis occurred only or rapid clinical deterioration.

Additional analysis within our complete cohort (n =190) showed

that the pre-test probability o IBD was 0.48 (i.e., 91/190), and that

utilizing a positive result o >200g/g provided a post-test prob-

ability o 0.77 (111 patients had a FC >200 g/g with 85 having

IBD), an increase o 60%.

FC levels in children with IBD are not influenced by sex,

age, IBD type, or disease location

Including all 91 children with IBD and categorizing the entire IBD

group by sex showed no difference between median FC levels in

males (1,265g/g (IQR 6581,864g/g)) and emales (1,250g/g

(IQR 8902,070g/g)) (P = 0.695). Tere were also no differences

between the sexes when the CD (P = 0.508), UC (P= 0.859), and

IBD-U (P = 0.999) groups were analyzed separately. Although

comparing age with FC level or the entire IBD group demon-

strated a signicant correlation (P = 0.037, Spearmans rho = 0.245),

Table 2. Non-IBD (control) diagnostic categories and median

fecal calprotectin values

Diagnostic category Number Median FC (IQR)

Irritable bowel syndrome 32 48 (21123)

Non-specific colitis 12 68 (25258)

No pathology identified 11 20 (20275)Post-infectious enteropathy 11 45 (20440)

Cows milk/wheat intolerance 8 67 (41115)

Pinworms 7 110 (29275)

Allergic enteropathy 5 80 (501508)

Celiac disease 3 350 (NA)

Miscellaneous 10 177 (61292)

Total 99

FC, fecal calprotectin; IBD, inflammatory bowel disease; IQR, interquartile range;

NA, not applicable.

Table 3. Symptoms and signs in control patients suggestive of

bowel inflammation/inflammatory bowel disease

Symptom/sign Percentage

Altered bowel habit 76

Abdominal pain 55

Rectal bleeding 48

Growth distortion 10

Vomiting 10

Recurrent mouth ulcers 3

Iron deficient anemia 2

Table 1. Characteristics of the inflammatory bowel disease and

control groups

Characteristic IBD group

Control

group

Difference

between groups

(Pvalue)*

Number of cases 91 99

Male sex (n(%)) 56 (62) 55 (56) 0.403

Age at endoscopy

(years (IQR))

12.6

(9.514.0)

9.3

(5.212.7)

< 0.001

Terminal ileal biopsy

obtained (n(%))

57 (63) 46 (46) 0.037

Median time from FC result

to endoscopy (days (IQR))

18 (744) 48 (2987) < 0.001

Median time from FC result

to blood result (days (IQR))

3 (09) 9 (330) NA

Median time from blood

result to endoscopy

(days (IQR))

13 (237) 56 (2993) NA

FC, fecal calprotectin; IBD, inflammatory bowel disease; IQR, interquartile

range; NA, not applicable.

*Pvalues as determined with 2or MannWhitney U-tests.




to the hepatic exure) and those with more limited disease (ParisE1E3, all with disease o varying extent rom the rectum yet dis-

tal to the hepatic exure) who had median FC levels o 1,480g/g

(IQR 9782,135g/g) and 963g/g (IQR 6912,135g/g), respec-

tively. Similarly, to evaluate all colonic IBD, CD patients with iso-

lated colonic or ileo-colonic disease (L2 or L3 only) had a similar

median FC level o 1,230g/g (IQR 4081,421g/g) compared

with those with UC and IBD-U combined (1,300g/g (IQR 925

2,200g/g)) (P =0.324).

FC does not vary significantly between the diagnostic

categories within the control group

Te median (IQR) or each o the control group diagnostic cat-

egories is shown in Table 2. Te miscellaneous group comprisedchildren with unctional abdominal pain (n= 2), colonic polyps

(n= 2), gastritis (n= 2), Meckels diverticulum (n= 1), pancreatic

insuffi ciency (n= 1), and perianal abscess (n= 1) and an as yet

undiagnosed growth restriction syndrome (n= 1). Tere was no

difference in the median FC values between the diagnostic catego-

ries (P = 0.575) with all median values < 200g/g (except or the

celiac disease group that only had three members). Te high third

quartile within the allergic enteropathy group was as a result o the

high FC level obtained in the 2-year-old girl mentioned above. As

bleeding per rectum ofen leads to a differential diagnosis o PIBD

we assessed the median FC in controls presenting with (n= 48)

this was lost when analyzed in a multivariate model that includedESR, CRP, and albumin (P = 0.375), likely reecting the act that

disease severity was a conounder.

o determine whether disease type or location inuenced FC

levels, detailed phenotypic inormation was collected rom our

Paediatric Inammatory Bowel Disease Cohort and reatment

Study database; their Montreal (16) classication or location at

diagnosis is shown in Supplementary Table 2. Tere was no di-

erence (P = 0.710) between CD, UC, and IBD-U patients, with

these three types having median FC levels o 1,258 g/g (IQR 710

1,671g/ g), 1250g/g (IQR 925 2,200g/g), and 1,463g/g (IQR

8982,125g/g), respectively.

Tere was neither any difference in the median FC levels

between those with upper intestinal CD location (1,440g/g(IQR 8852,034g /g)) and those without (1,220g/g (IQR 400

1,340g/g)) as dened as the presence or absence o Montreal L4

disease (P =0.077), nor any difference observed when compar-

ing the median FC levels in CD patients with any ileal (L1L4 or

L3L4) disease (1,266g/g (IQR 8751,757g/g)) and those with-

out (1,295g/g (IQR 4941,832g/g)) (P= 0.694).

o allow meaningul numeric comparison o UC and IBD-U

disease location both groups were combined and each patient

re-classied according to the newly described Paris classication

o PIBD (17). Tis demonstrated no difference (P= 0.536) between

those with extensive pancolonic disease (Paris E4, disease proximal

Table 4. Measures of diagnostic accuracy for increasing levels of fecal calprotectin and commonly measured blood parameters in children

with suspected inflammatory bowel disease

Sens (95% CI) Spec (95% CI) NPV (95% CI) PPV (95% CI)

Youden Indexa

(95% CI) LR + ve (95% CI)

Fecal calprotectin

Cutoff (g/g)

>50 0.98 (0.921.00) 0.44 (0.340.55) 0.96 (0.850.99) 0.62 (0.530.70) 0.42 (0.270.55) 1.8 (1.52.1)

>100 0.97 (0.910.99) 0.59 (0.480.68) 0.95 (0.860.99) 0.68 (0.590.76) 0.55 (0.380.68) 2.3 (1.83.0)

>200 0.93 (0.860.98) 0.74 (0.640.82) 0.92 (0.840.97) 0.77 (0.670.84) 0.67 (0.500.80) 3.6 (2.55.0)

>300 0.89 (0.810.95) 0.83 (0.740.90) 0.89 (0.810.95) 0.83 (0.740.90) 0.72 (0.540.84) 5.2 (3.38.0)

>800 0.73 (0.620.81) 0.95 (0.890.98) 0.79 (0.710.86) 0.93 (0.840.98) 0.68 (0.520.80) 14.5 (6.134.4)

Blood parameters (using normal pediatric values outlined in Supplementary Table 1)

Parameter

Hemoglobin 0.64 (0.530.73) 0.79 (0.630.87) 0.69 (0.590.78) 0.75 (0.640.84) 0.43 (0.230.61) 3.1 (2.04.7)

Total WCC 0.09 (0.040.17) 0.99 (0.940.99) 0.53 (0.450.60) 0.89 (0.521.00) 0.08 ( 0.02 to 0.18) 8.2 (1.06.4)

Platelets 0.43 (0.320.54) 0.92 (0.850.97) 0.62 (0.530.70) 0.84 (0.710.94) 0.35 (0.170.50) 5.6 (2.611.8)

ESR 0.67 (0.570.77) 0.89 (0.810.95) 0.74 (0.640.82) 0.86 (0.750.93) 0.56 (0.370.72) 6.1 (3.411.2)

Albumin 0.22 (0.140.33) 0.99 (0.940.99) 0.56 (0.490.64) 0.95 (0.761.00) 0.21 (0.080.33) 20.4 (2.8149.1)

CRP 0.55 (0.440.66) 0.91 (0.830.96) 0.67 (0.580.76) 0.86 (0.740.94) 0.46 (0.280.62) 6.3 (3.112.5)

CI, confidence interval; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; LR + ve, positive likelihood ratio; NPV, negative predictive value; PPV, positive predic-

tive value; sens, sensitivity; spec, specificity; WCC, white cell count.aYouden Index, sensitivity + (specificity-1).



46

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Henderson et al.

and without (n= 51) a history o per rectum blood, revealing no

difference in median FC values o 60g/g (IQR 20218g/g) and

65g/g (IQR 25275), respectively (P= 0.512). In addition, no

difference was demonstrated when correlating age with FC levels

across all control group diagnostic categories (P = 0.051, Spear-

mans rho = 0.197).

Medications, including PPIs, do not seem to influence

FC levels

Within the IBD group 24% o PIBD cases and 33% o controls were

on any oral medication at the time o FC sampling (P = 0.219);

however, no children were currently receiving medication directly

related to their suspected bowel inammation. Combining all

patients, there was no difference (P = 0.519) in median FC between

those currently prescribed (275g/g (IQR 401,265)) or not pre-

scribed (385g/g (IQR 601,275g/g)) any medication. Within

the control group the median FC level o patients prescribed PPIs

(n= 10) was 108g/g (IQR 20240g/g) that was similar to those

not on PPIs (n= 89) (60g/g (IQR 21240g/g)) (P = 0.906).

FC performs better than commonly used blood parameters

as a diagnostic biomarker during the evaluation of children

with suspected IBD

o compare the perormance o FC with six commonly used

blood parameters, blood results taken at a similar time as the FC

measurement were analyzed (median time difference 6 days (IQR

128 days); see Table 1). Te availability o each blood param-

eter or each group is shown in Supplementary Table 3. Te

diagnostic accuracy o each blood parameter in comparison to

FC is outlined in Table 4. Figure 2 demonstrates that the area

under the curve or FC was greater than all six blood parametersat 0.93 (95% CI 0.890.97), and signicantly higher than ESR

(P = 0.011), CRP (P = 0.006), total white cell count (P < 0.001),

hemoglobin (P < 0.001), and platelet count (P < 0.001), but was

not signicantly greater than albumin (P = 0.374). Further analy-

sis o albumin as a predictor or IBD revealed that the optimum

threshold was in act 41g/l (within our normal pediatric reerence

range o 3350 g/l), with the relevant diagnostic specicity using

our normal lower limit o normal being ar inerior (Table 4).

However, by combining FC and serum albumin (using an opti-

mized ormula o (60 + FC/100g/g) (serum albumin in g/L))

it can be seen that the area under the curve is improved at 0.96

(95% CI 0.930.99); however, this was not signicantly different

to FC alone (P= 0.227). Using the above ormula and utilizing acutoff o 20 produced the ollowing diagnostic accuracy indica-

tors: sensitivity 0.97 (95% CI 0.900.99), specicity 0.81 (95% CI

0.710.89), negative predictive value 0.96 (95% CI 0.880.99), and

positive predictive value 0.84 (95% CI 0.760.91).

DISCUSSION

Our results demonstrate that FC is a highly useul biomarker dur-

ing the initial investigation o suspected PIBD. Using only chil-

dren presenting with suspected bowel inammation, without any

known GI diagnosis, and subsequently undergoing their rst ull

endoscopic investigation, we clearly show that FC is markedly

raised in those with IBD, with no inuence o IBD type or loca-

tion. We have also provided evidence that FC perorms better than

all commonly used blood parameters with an area under the curve

o 0.93 (95% CI 0.890.97). Although some would argue that FC is

not needed in a classical presentation o CD or UC, our data show

the utility o FC across the whole clinical spectrum o all types o

IBD (e.g., those without luminal CD or with mainly extraintestinal

symptoms) and, even more importantly, show the potential utility

o FC in deciding which children and teenagers presenting withpossible gut inammation do not need endoscopic assessment.

Calprotectin is a 24-kDa heterodimer composed o two cal-

cium-binding proteins belonging to the S100 group o proteins

(S100A8 and S100A9) (18), constituting 60% o the cytosolic

protein in human neutrophils (6). FC has both bacteriostatic and

ungistatic properties (19,20), mainly mediated by zinc chelation

via histidine-rich regions o the calprotectin molecule (21). In

PIBD FC has been shown to correlate with endoscopic severity at

colonoscopy (22), disease activity in UC (23), and has also dem-

onstrated useulness in predicting disease relapse (24). Tere are

currently only a limited number o studies using FC during the

Specificity

Sensitivity

0.0

0.2

0.4

0.6

0.8

1.0

1.0 0.8 0.6 0.4 0.2 0.0

Calprotectin/Albumin combined (0.96 (0.930.99))

Fecal calprotectin (0.93 (0.890.97))

Albumin (0.91 (0.860.95))

ESR (0.84 (0.770.90))

CRP (0.83 (0.770.89))

Platelets (0.79 (0.730.86))

Standardized Hb (0.78 (0.710.85))

Standardized WCC (0.70 (0.630.78))

Variable (AUC (95% CI))

Figure 2. Receiver operating characteristic (ROC) curves and correspond-

ing area under the curve (AUC) for fecal calprotectin and commonly

measured blood parameters in pediatric patients with suspected IBD. CI,

confidence interval; CRP, C-reactive protein; ESR, erythrocyte sedimenta-tion rate; Hb, hemoglobin; WCC, white cell count.




current clinical practice, with children ofen attending general

practice or a general pediatrician with non-specic GI symp-

toms beore assessment by a pediatric gastroenterologist. Delay

to endoscopic assessment o suspected pediatric IBD has been a

major issue in many countries including the United Kingdom,

although changes in the National Health Service service design in

Scotland has markedly reduced this waiting time over the period

rom 2005 to 2011. Tird, another potential difference rom previ-

ous studies is the use o a relatively low upper limit o FC assay. For

example Perminow et al.(29) were able to demonstrate a signi-

cantly higher FC level in those with CD vs. UC (1,181g/g, range

116,123g/g; 1,250g/g, range 138,625g/g, respectively) due

in all likelihood to their (undisclosed) higher reerence range.

Finally, two potential conounding actors in this study were the

differing rates o I biopsy in the IBD and control groups and

the effect o oral medications. With regard to these aspects our

analysis has shown that I intubation rates were likely a result o

the higher age o the IBD group, that removal o those without a

I biopsy did not change our main results o diagnostic accuracyand that I intubation rates did not differ between those with and

without a FC level available at endoscopy; we, however, acknowl-

edge that this study was not powered to look at the effects o drugs

on FC levels.

Acknowledging the relative weakness o retrospective study

design, we are condent that (i) our robust choice o inclusions

(i.e., only children presenting with suspected bowel inamma-

tion, without known GI diagnosis, and subsequently undergoing

their rst ever endoscopic investigation); (ii) our evaluation o all

o the FC levels perormed in our region over the 6-year-study

period; (iii) our ability to review and ollow-up all suspected

pediatric cases o gut inammation in a dened geographi-cal region (one child was initially placed in the no pathology

identied control group but was very recently diagnosed as

non-specic colitis and was re-assigned as such); and (iv) our

knowledge o all new regional cases o PIBD (within pediatric

services in primary, secondary, and tertiary care) to the end o

December 2011, when taken together, add considerable con-

dence to the generalizability o these ndings to all PIBD services

worldwide.

On the basis o our clinical experience, laboratory guidance

and relevant literature (23), we have routinely used a FC cutoff o

200g/g as our threshold or the suspicion o a new IBD diagno-

sis, accepting the need or ull clinical history, examination, and

other blood tests. Tis has been validated by our results with theYouden index, suggesting a FC level between 200 and 300g/g

providing an optimum sensitivity/specicity. Although several

newly described serum markers have been identied as possible

markers o IBD, these are ofen present at higher levels in certain

sub-phenotypes (31) or are only available as research tools (32).

Commonly measured blood parameters remain the investigations

o choice, with ESR (33) and CRP (34) currently providing the best

indication o possible IBD, but have a relatively poor diagnostic

accuracy, especially specicity. Previous work by our group dem-

onstrated that the use o common blood tests could be enhanced

signicantly by the inclusion o FC in a panel o inammatory

initial investigation o pediatric bowel inammation (i.e., beore

endoscopic conrmation o IBD) (4,2529). Tese studies have

ofen included small numbers o IBD patients. Although some

have reported similar ndings to our study with regard to median

FC levels at diagnosis (28), they ofen ailed to provide a detailed

analysis o sub-phenotypic characteristics in a truly representative

group o potential IBD patients (30).

Our extensive clinical use o FC as a biomarker in GI-related

disease or >7 years leads to this study having several strengths

in relation to study design and analyzes perormed. First, our

regional IBD cohort is representative o our larger Scottish nation-

wide cohort with regard to demographic composition (1) and

disease location at diagnosis (10). Previous studies ofen excluded

younger children (23,30), those with a high suspicion o IBD (26)

and those on medications (28), potentially skewing subsequent

analyzes. Tis is reected in our modest pre-test probability

o 0.48, which is lower than reported in two recently published

relevant papers on FC usage (28,29). In addition, previous groups

ofen used a control group o patients with no known GI symp-toms or signs to generate sensitivity and specicity (23,27), which

is certainly not applicable in a real world clinical setting o a

pediatric GI service. In act within our study a selection bias does

occur rom the entire cohort assessed using FC levels, but this

bias works against the test as only sicker children with increased

FC levels are likely to be reerred to specialist GI services and

undergo endoscopy. Second, only including those undergoing ull

endoscopy, and our reporting o small bowel investigation within

the IBD group, has ensured robust phenotyping o all patients;

many studies include only patients undergoing colonoscopy (4)

or provide no details o endoscopic investigation (27). Tird, our

large study group (n= 190) has allowed urther meaningul exam-ination o particular sub-groups. Previous studies have requently

combined those with previously conrmed IBD (23) (thereore

presenting a heterogeneous group with both de novo disease

and established IBD), or presented small numbers o each IBD

type (28).

Te retrospective design o our study does, however, pro-

duce potential limitations. First, as the clinical utility o FC was

not evaluated during the initial decision to perorm endoscopic

assessment, we were unable to determine whether or not the FC

level contributed to the gastroenterologists choice to perorm

endoscopy. Similarly, the inuence o the various blood param-

eters on the ultimate decision to perorm endoscopy could not be

elucidated. Tis is an important actor when assessing the useul-ness o any biomarker in this context as prior knowledge o the FC

result may have led to the avoidance o unnecessary endoscopic

procedures, or conversely the delay in IBD diagnosis (which may

have occurred in two o our patients i FC level had been used in

isolation at diagnosis). Second, during the study we collected data

within a time period o 6 months beore endoscopy with other

prospective studies standardizing the sampling time (e.g., 1 week

beore endoscopy) to potentially eliminate a conounding effect

o variable disease activity on their results (22). Although useul

during the initial phases o determining the diagnostic accuracy

o a certain biomarker, our approach is more comparable with



48

PEDIAT

RICS

Henderson et al.

markers during the investigation o suspected IBD (35). Tis has

been urther enhanced with the development o a combined FC

and serum albumin score described above, which provided a

better (although not statistically signicantly) area under the

curve than FC alone.

GI endoscopic assessment is diffi cult or children, with the need

or hospital or day-case admission. For the children this involves

asting, bowel preparation (i undergoing lower GI evaluation),

and anesthesia/sedation (admission to a day-case unit and total

intravenous anesthesia usage is our current design or elective

procedures). For their parents, anxiety and time away rom

employment or dependent younger children is also a potential

issue. It is also expensive, with a wide variation between differ-

ent countries. By comparison FC can be obtained by providing

the amily with instructions, a sample pot, a prelled laboratory

orm and suitable packaging or postage to the appropriate IBD

unit. It is relatively cheap in the United Kingdom; currently, our

National Health Service laboratory pays US$785 per kit (Phi-

Cal est) equating to US $10.90 per sample. Te National HealthService requests are charged at US $40 per test as this currently

used test remains relatively labor intensive (K Kingstone, personal

communication).

In conclusion, we have shown that FC is signicantly raised

in children with IBD compared with non-IBD, scoped controls,

and have also demonstrated that FC provides greater diagnostic

accuracy than other commonly used blood parameters. We eel

that the characteristics o both groups and the timing o their

investigations represent a true reection o the investigative

procedures carried out in children with suspected bowel inam-

mation and that FC should now be used routinely during the

initial assessment o these children. Further studies are nowrequired to ully determine the effect o FC measurement on

endoscopy rates, with the potential to reduce the number o

children undergoing endoscopic assessment or suspected

IBD, thereore reducing costs, streamlining pediatric GI endos-

copy services, and reducing both child and amily distress and

inconvenience.

ACKNOWLEDGMENTS

We thank Dr John Morrice, Mrs Hazel Drummond, and Dr Carol

Dryden or their help with data collection.

CONFLICT OF INTEREST

Guarantor of the article: David C. Wilson, MD, FRCP, FRCPCH.Specic author contributions:P.H. and D.C.W. prepared the

manuscript with additions, comments, and corrections by all the

authors. P.H., S.J.L., A.C., K.K., and P.R. collected the data. P.H. and

N.A.K. analyzed the complete data set. P.M.G. and D.C.W. are the

IBD clinical leads within the study center.

Financial support:P.H. is unded by a Medical Research Council

project grant or Paediatric Inammatory Bowel Disease Cohort

and reatment Study (no. G0800675). N.A.K. is unded by grants

rom the Chie Scientist Offi ce in Scotland (no. EM/75) and

Cure Crohns Colitis.

Potential competing interests:None.

Study Highlights

WHAT IS CURRENT KNOWLEDGE

3Pediatric inflammatory bowel disease (PIBD) represents aphenotypically distinct subset of disease.

3A recent meta-analysis concluded that the discriminativepower of fecal calprotectin (FC) to safely exclude IBD was

significantly better in adults than in children.

3However, the median number of PIBD patients withinprevious studies evaluating FC was only 31 and not all

represented new diagnoses.

3A large, comprehensive study comparing the diagnosticaccuracy of FC with other commonly measured blood

parameters has not yet been performed.

WHAT IS NEW HERE

3The median fecal calprotectin (FC) value during thediagnosis of pediatric inflammatory bowel disease (PIBD)

is significantly higher than non-IBD controls undergoing

upper and lower endoscopy.

3FC at diagnosis is not influenced by age, sex, PIBD type,or disease location.3FC provides the clinician with a significantly greater degree

of diagnostic accuracy than other commonly measured

blood parameters.

3The routine use of FC in the pediatric setting shouldsignificantly enhance our ability to more accurately

screen children for IBD.

REFERENCES1. Henderson P, Hansen R, Cameron FL et al.Rising incidence o pediatric

inammatory bowel disease in Scotland. Inamm Bowel Dis 2011.Published online rst:17 June 2011. doi:10.1002/ibd.21797.

2. Benchimol EI, Fortinsky KJ, Gozdyra P et al.Epidemiology o pediatricinammatory bowel disease: a systematic review o international trends.Inamm Bowel Dis 2011;17:42339.

3. Beniwal P, Harrell L. Te status o diagnostic markers or inammatorybowel disease. Curr Gastroenterol Rep 2010;12:47984.

4. Diamanti A, Panetta F, Basso MS et al.Diagnostic work-up o inammatorybowel disease in children: the role o calprotectin assay. Inamm Bowel Dis2010;16:192630.

5. Schoeper AM, rummler M, Seeholzer P et al.Discriminating IBD romIBS: comparison o the test perormance o ecal markers, blood leukocytes,CRP, and IBD antibodies. Inamm Bowel Dis 2008;14:329.

6. Roseth AG, Fagerhol MK, Aadland E et al.Assessment o the neutrophildominating protein calprotectin in eces. A methodologic study. Scand JGastroenterol 1992;27:7938.

7. van Rheenen PF, Van de Vijver E, Fidler V. Faecal calprotectin or screeningo patients with suspected inammatory bowel disease: diagnosticmeta-analysis. BMJ 2010;341:c3369.

8. Lennard-Jones JE. Classication o inammatory bowel disease. Scand JGastroenterol 1989;24 (Suppl 170): 26.

9. IBD working group o the European Society or Paediatric Gastroenterol-ogy Hepatology and Nutrition. Inammatory bowel disease in children andadolescents: recommendations or diagnosis - the Porto criteria. J PediatrGastroenterol Nutr 2005;41:17.

10. Van Limbergen J, Russell RK, Drummond HE et al.Denition o phe-notypic characteristics o childhood-onset inammatory bowel disease.Gastroenterology 2008;135:111422.

11. Stevenson M. epiR: Functions or analysing epidemiological data. (R pack-age version 0.9-33). Available rom: http://cran.r-project.org/web/packages/epiR/index.html (accessed: 2 November 2011).

12. Robin X, urck N, Hainard A et al.pROC: an open-source package orR and S+ to analyze and compare ROC curves. BMC Bioinormatics2011;12:77.

13. Youden WJ. Index or rating diagnostic tests. Cancer 1950;3:325.




26. Canani RB, de Horatio L, errin G et al.Combined use ononinvasive tests is useul in the initial diagnostic approach to a childwith suspected inammatory bowel disease. J Pediatr GastroenterolNutr 2006;42:915.

27. Bonnn oms A, Vila Vidal M, Rosell Camps A. Fecal calprotectin as abiomarker to distinguish between organic and unctional gastrointestinaldisease. Rev Esp Enerm Dig 2007;99:68993.

28. Sidler MA, Leach S, Day AS. Fecal S100A12 and ecal calprotectin asnoninvasive markers or inammatory bowel disease in children. InammBowel Dis 2008;14:35966.

29. Perminow G, Brackmann S, Lyckander LG et al.A characterization inchildhood inammatory bowel disease, a new population-based inceptioncohort rom South-Eastern Norway, 200507, showing increased incidencein Crohns disease. Scand J Gastroenterol 2009;44:44656.

30. Fagerberg UL, Loo L, Lindholm J et al.Fecal calprotectin: a quantitativemarker o colonic inammation in children with inammatory boweldisease. J Pediatr Gastroenterol Nutr 2007;45:41420.

31. Russell RK, Ip B, Aldhous MC et al.Anti-Saccharomyces cerevisiaeantibodies status is associated with oral involvement and disease severityin Crohn disease. J Pediatr Gastroenterol Nutr 2009;48:1617.

32. Lehrke M, Konrad A, Schachinger V et al.CXCL16 is a surrogatemarker o inammatory bowel disease. Scand J Gastroenterol 2008;43:2838.

33. Mack DR, Langton C, Markowitz J et al.Laboratory values or chil-

dren with newly diagnosed inammatory bowel disease. Pediatrics2007;119:11139.

34. sampalieros A, Griffi ths AM, Barrowman N et al.Use o C-reactiveprotein in children with newly diagnosed inammatory bowel disease.J Pediatr 2011;159:3402.

35. Quail MA, Russell RK, Van Limbergen JE et al.Fecal calprotectincomplements routine laboratory investigations in diagnosingchildhood inammatory bowel disease. Inamm Bowel Dis 2009;15:7569.

14. DeLong ER, DeLong DM, Clarke-Pearson DL. Comparing the areasunder two or more correlated receiver operating characteristic curves:a nonparametric approach. Biometrics 1988;44:83745.

15. Hanley JA, McNeil BJ. A method o comparing the areas under receiveroperating characteristic curves derived rom the same cases. Radiology1983;148:83943.

16. Silverberg MS, Satsangi J, Ahmad et al.oward an integrated clinical,molecular and serological classication o inammatory bowel disease:report o a working party o the 2005 Montreal World Congress oGastroenterology. Can J Gastroenterol 2005;19 (Suppl A): 536.

17. Levine A, Griffi ths A, Markowitz J et al.Pediatric modication o theMontreal classication or inammatory bowel disease: the Parisclassication. Inamm Bowel Dis 2011;17:131421.

18. Fagerhol MK, Dale I, Anderson . Release and quantitation o a leucocytederived protein (L1). Scand J Haematol 1980;24:3938.

19. Lusitani D, Malawista SE, Montgomery RR. Calprotectin, an abundantcytosolic protein rom human polymorphonuclear leukocytes, inhibits thegrowth o Borrelia burgdoreri. Inect Immun 2003;71:47116.

20. Murthy AR, Lehrer RI, Harwig SS et al.In vitrocandidastatic properties othe human neutrophil calprotectin complex. J Immunol 1993;151:6291301.

21. Loomans HJ, Hahn BL, Li QQ et al.Histidine-based zinc-binding sequencesand the antimicrobial activity o calprotectin. J Inect Dis 1998;177:8124.

22. Bunn SK, Bisset WM, Main MJ et al.Fecal calprotectin: validation as anoninvasive measure o bowel inammation in childhood inammatory

bowel disease. J Pediatr Gastroenterol Nutr 2001;33:1422.23. Bremner A, Roked S, Robinson R et al.Faecal calprotectin in children with

chronic gastrointestinal symptoms. Acta Paediatr 2005;94:18558.24. Walkiewicz D, Werlin SL, Fish D et al.Fecal calprotectin is useul in

predicting disease relapse in pediatric inammatory bowel disease.Inamm Bowel Dis 2008;14:66973.

25. Fagerberg UL, Loo L, Myrdal U et al.Colorectal inammation is wellpredicted by ecal calprotectin in children with gastrointestinal symptoms.J Pediatr Gastroenterol Nutr 2005;40:4505.


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