Performance Characteristics - BÜHLMANN Quantum Blue Manuel D'utilisation

• Results may not be clinically applicable to children less
than 4 years of age who have mildly increased fecal
calprotectin levels (ref. 8-11).
INTERPRETATION OF RESULTS
DISTINGUISHING ORGANIC DISEASE FROM
FUNCTIONAL GASTROINTESTINAL DISEASE
The determination of fecal calprotectin levels can be used
as a reliable and simple aid in distinguishing organic from
functional gastrointestinal diseases (ref. 1-7).
The result categories are based on data from clinical
studies performed by BÜHLMANN and are BÜHLMANN's
recommendations. All test results should be interpreted in
conjunction with information available from the patient's
clinical symptoms, medical history, and other clinical and
laboratory findings.
Clinical thresholds
The following data were established with the BÜHLMANN
fCAL ® ELISA (order code: EK-CAL).
Results from 58 clinical samples from patients diagnosed
with IBS and 131 clinical samples from patients diagnosed
with IBD, from an international clinical study, were analyzed
to obtain the values described in table 3.
Calprotectin
Interpretation
concentration
< 80 µg/g Normal
80 - 160 µg/g Gray-zone/Borderline
> 160 µg/g Elevated
Calprotectin values below 80 μg/g
Fecal calprotectin values <80 µg/g are not indicative of
inflammation in the gastrointestinal tract. Patients with low
calprotectin levels are not likely to be in need of invasive
procedures to determine the inflammation cause.
Calprotectin values between and equal to 80 and
160 μg/g
Mid-fecal calprotectin levels between and equal to 80 and
160 µg/g, also called gray-zone levels, are not directly
indicative of an active inflammation requiring immediate
follow-up with invasive testing. However, the presence of
inflammation cannot be excluded. Re-evaluation of fecal
calprotectin levels after 4 to 6 weeks is recommended to
determine the inflammatory status.
Calprotectin values above 160 μg/g
Fecal calprotectin values >160 µg/g are indicative of
neutrophil infiltrate in the gastrointestinal tract; therefore,
this may signal the presence of active inflammatory
disease. Appropriate further investigative procedures by
specialists are suggested to achieve an overall clinical
diagnosis.
Clinical evaluation
The ability of the BÜHLMANN fCAL
between patients with IBD and other non-inflammatory GI
disorders, including IBS, was tested in a clinical study with
a total of 337 adult and pediatric patients. One hundred and
thirty five (135) patients had a final diagnosis of IBD
(Crohn's disease, ulcerative colitis or indeterminate colitis),
130 patients suffered from IBS and 72 patients presented
Release date: 2020-10-30
Follow-up
None
Follow-up within 4 – 6
weeks
Repeat as needed
Table 3
ELISA to discriminate
®
with abdominal pain and/or diarrhea, or other GI-related
non-inflammatory conditions (refer to table 4). Final
diagnosis was supported by endoscopic as well as other
clinical findings.
A clinical sensitivity of 93.3% at 80 µg/g and a clinical
specificity of 83.7% at 160 µg/g, can be reached in the
differentiation between
inflammatory conditions, including IBS. ROC curve analysis
resulted in an AUC of 0.923 (refer to table 5).
A clinical sensitivity of 93.3% at 80 µg/g and a clinical
specificity of 85.4% at 160 µg/g, can be reached in the
differentiation between IBD and IBS. ROC curve analysis
resulted in an AUC of 0.933 (refer to table 6).
The optimal cut-off combination for these patient pools
could be defined by ROC analysis at 80 µg/g and 160 µg/g
calprotectin, which is slightly more stringent than a
combination of a more sensitive lower cut-off of 50 µg/g
with lower performance in specificity, and an upper cut-off
of 200 µg/g with slightly lower sensitivity (table 7 and 8).

PERFORMANCE CHARACTERISTICS

Limit of Blank (LoB): <7 µg/g calprotectin
The LoB has been established in accordance with CLSI
protocol EP17-A in three independent runs using three
different lots of test cassettes with 60 blank values in total
by using extraction buffer as a sample.
Limit of Detection (LoD): 15 µg/g calprotectin
The LoD has been established with two stool extracts with
concentrations of 14.5 and 28.5 µg/g. The samples were
measured with three different lots of test cassettes in three
independent runs of 10 replicates each, set up within 10
minutes. The averaged SD values were determined and
the LoD has there from been calculated in accordance with
CLSI protocol EP17-A.
Limit of Quantification (LoQ):
Lower LoQ: ≤30 µg/g calprotectin
Upper LoQ: ≥300 µg/g calprotectin
The LoQ has been established with seven stool extracts at
concentrations between 14.5 and 622 µg/g. The samples
were measured with three different lots of test cassettes in
three independent runs of 10-20 replicates each, set up
within 10 minutes and averaged. The resulting precision
profile is shown in figure 2. The limit of quantification
corresponds to the concentration of calprotectin with an
imprecision below 25% CV allowing a quantitative
measurement within the range from 30 (lower LoQ) to
300 µg/g (upper LoQ).
Linearity
Four stool samples
concentrations were extracted according to the assay
procedure. The extracts were diluted with extraction buffer
and each dilution was subsequently assayed on two test
cassette according to the assay procedure and averaged
for each test point. The results showed linearity within the
indicated measuring range of 30 to 300 µg/g of the
Quantum Blue ® fCAL assay for all 4 samples (R
0.995). One example is shown in (figure 3). The average
difference between measured and expected concentrations
was 2% corresponding to a recovery of 98%. The recovery
varied between 84-114%.
6/36
IBD and GI-related
with elevated calprotectin
2 = 0.986-
Quantum Blue® fCAL
non-