You’ll find answers to all of the most commonly asked questions (FAQs) about Calprotectin testing and products below. If you can’t find the answer you’re looking for, please contact us.


What are Calprotectin Assays used for?

Calprotectin tests are used in a number of different clinical applications:

  • Differentiation between IBD and IBS (organic inflammation from functional symptoms)
  • Estimation of the degree of gastrointestinal inflammation
  • Relapse prediction- calprotectin has been shown to be an indicator for IBD relapse
  • Therapeutic monitoring- quantifying calprotectin levels helps validate bowel inflammation status and can also aid in treatment compliance and optimisation
If I implement a Calprotectin assay service in my hospital, how many colonoscopies would be avoided?

40% of all colonoscopies are unnecessary if the patient has IBS rather than IBD. In these cases, testing a patient’s Calprotectin first would result in reduced demands for endoscopies, a significant improvement in waiting times and considerable cost-savings.

Will the waiting times for colonoscopies be reduced if we test a patient's Calprotectin first?

Yes, Ingvar Bjamason at King’s College, London reduced her waiting list from 28 weeks to 8 days.

What are the cut-off levels for the Calprotectin assays?


Most hospitals are following the York Calprotectin Care Pathway, which is endorsed by BSG, NICE and Crohn’s & Colitis UK:

  • <100µg/g = IBD is unlikely
  • 100 – 250µg/g = Intermediate result. Repeat the test in 2 weeks
  • >250µg/g = Likely IBD refer to secondary care


With IBD positive patients the monitoring recommended cut-offs are:

  • <100µg/g = Low risk of flare
  • 100 – 300µg/g = Patient may need closer monitoring
  • >300µg/g = Repeat test. If the result remains high then the patient is at risk of flare and other investigations should be initiated.

Sample Collection

What stool sample should the patient take for Calprotectin?

It is recommended that the patient collects the FIRST stool in the morning, as it has been in the gut overnight and so is likely to contain the highest level of calprotectin. If the patient has had a colonoscopy then the sample needs to be taken the third morning after the colonoscopy. Stools can be stored without refrigeration for up to 3 days, but it is ideal to test the sample as soon as possible.

How do I store my samples?

Collect stool samples into plain tubes and store them refrigerated at 2-8°C for up to 6 days. Freezing of raw samples may result in slightly increased Calprotectin concentrations due to Neutrophiles present in the sample. For longer term storage keep the extracted samples at -20ºC. The extracts are stable for at least 4 months.

Extraction Procedures

How do I convert Grams of Stool to ml and vice versa? Does 1g of stool = 1 ml?

In short, yes.

Can you still use very liquid samples? If so, how would I perform the extraction?

Yes you can. With the Roche tubes you would pipette 80µl of the sample into the tube then add 4mls of extraction buffer provided with the fCAL ELISA and Quantum Blue assays. With the CALEX you can remove the blue cap and pipette 10µl of sample into the tube.

Are the extraction devices provided with the assay kits?

Extraction devices are supplied separately to allow laboratories the choice of method. Two extraction devices are available, Roche (B-CAL-RD) and CALEX (B-CALEX-C50, B-CALEX-C200 and B-CALEX-C500).

Why is it necessary to avoid mucous in the stool?

Alpha Laboratories has been informed by Dr Arne Roseth that the mucous contains glycoproteins that can bind with Calprotectin and not release it. Usually there are sections of the samples that are free from mucous and more solid. If a sample is mostly mucous it is likely not first morning stool. Mucous can affect the reproducibility of the data.

Can blood in stools cause a false positive result?

Blood contains white cells and so there will be some level of calprotectin present which can result in a mildly elevated result.
However, the level of calprotectin in blood isn’t high, so the volume is not usually sufficient to cause a falsely positive result in patients with IBD (cut – off level is usually around 250 – 300µg/g).

See Vavricka S.R et al. The Vampire Study: Significant elevation of faecal calprotectin in healthy volunteers after 300 ml blood ingestion mimicking upper gastrointestinal bleeding.


Why should I buy a Calprotectin assay from Alpha Laboratories?


  • Results trusted by reference centres
  • You can trust in our integrity


  • Long standing relationship with Bühlmann
  • Relationships with NICE, BSG, QIPP, CEP, EQA
  • Relationships with Key Opinion Leaders


  • Training, applications, workshops, business case


  • Established company
  • Experienced sales force


  • In-depth knowledge of calprotectin and its applications
  • Alpha Laboratories have been involved since the early introduction of calprotectin testing and have been instrumental in its adoption for clinical use in the UK


  • Quality results, clinical correlation, extensive publications, standardisation across range
Why should I use a Calprotectin Assay from Bühlmann?

All the Bühlmann assays are standardised together so the results are the same and you can use consistent cut-offs. Therefore, there is no difference in the answers given by any of the Calprotectin assays.
The Bühlmann kits are all easy to use and reagents and calibrators are supplied in stable ready to use formats.

There is an assay to suit your setting: laboratory, clinic, home testing, high, medium or low throughput. There is a large amount of independent literature available that demonstrates the superior linearity and clinical correlation of the Bühlmann Calprotectin assays. Please visit our literature page for some of these published papers and posters.

Are the Calprotectin assays ready to use?

Yes. All the required reagents, standards and calibrators are provided ready to use. Only the wash buffer for the fCAL ELISA requires reconstitution.

Do I have to order standards and controls separately?

The Calprotectin fCAL ELISA and Quantum Blue assays have all controls and standards contained within the kit.
The fCAL turbo has the controls and calibrators available separately so that the laboratories can tailor their individual requirements.

How often do I run standards and controls on the Calprotectin assays?

Standards and controls are run every batch when using the Calprotectin fCAL ELISA.
It is recommended to run the Quantum Blue controls (Low and High) at the change of every lot number. Or once a week if the Quantum Blue is not used on a regular basis.
Controls need to be included with each run on fCAL turbo but the calibration is stable for 1-2 months (depending on the analyser).

What are the Calibrators and Controls?

Extracted and purified Calprotectin from serum.

What is the shelf life of the Calprotectin assays?

The Calprotectin fCAL ELISA shelf-life is 18 months after manufacture.
The Quantum Blue assay shelf-life is 12 months after manufacture.
The fCAL turbo shelf-life is 12 months after manufacture and has a 2 month on board stability for reagents.

What is the difference between the 10-600µg/g and 30-1800µg/g Calprotectin ELISA protocols?

Both protocols can be used with the same kit. The only difference between the two is that the lower range uses a dilution factor of 1:50 and the higher range uses a dilution factor of 1:150.

Are the Calprotectin assays subject to interference from other compounds?

Compound / Drug Result Corresponding Daily Dose
Hemoglobin / No interference up to 20 mg/g stool
Ferro-Gradument (ferrous-sulfate) / No interference up to 0.04 mg/ml 315 mg
Prednison / No interference up to 0.125 mg/ml 9 g
Imurek / No interference up to 0.07 mg/ml 560 mg
Vitamin E / No interference up to 0.04 mg/ml 300 mg
Vancomycin / No interference up to 0.8 mg/ml 6 g
Pentasa / No interference up to 2.0 mg/ml 15 g
Asacol / No interference up to 0.5 mg/ml 3.7 g
Actavis / No interference up to 0.07 mg/ml 525 mg
Ciprofloxacin / No interference up to 0.38 mg/ml 3.6 g
Trimetoprim / No interference up to 0.128 mg/ml 960 mg
Sulfametoxazol / No interference up to 0.64 mg/ml 4.8 g
Multiple Vitamins / No interference up to 3 tablets/day
Analytical specificity: No cross reactivity/interferences detected.

What is the internal storage capacity of the QB Desktop/Quantum Blue Reader?

The internal storage capacity of the Reader is 100 runs. After 90 runs, the Reader informs the user the upload or better said download the stored data (result table) from the reader, otherwise the data will be overwritten as soon as 100 runs are achieved. If the stored data are not downloaded (e.g. by LF Manage or LF Control software), they will be simply overwritten and the Reader stops signalling it as soon as the first data set is overwritten with the 101st. Please also refer to the software manual, p. 12 and 14.

Are reagent rental deals available?

Yes, reagent rental options are available on the Quantum Blue, the DS2 ELISA processor and the BA200 analyser. Please contact us to discuss your needs.

I already have an ELISA processor. Is it possible to put the Calprotectin ELISA on to our own system?

Yes, there is CE marked protocols available for the Dynex DS2 and DSx as well as protocols available for the Triturus, etc. The protocol is very easy to set up and we will work with the laboratory and the supplier of the analyser in order to get the application running.

How long does it take to run a Calprotectin assay?

The Calprotectin fCAL ELISA takes around 75 minutes to run.
The Quantum Blue takes 12 minutes to run.
The fCAL turbo takes 10 minutes to run.

EQA Scheme

What EQA schemes are available for Calprotectin?

There are several schemes currently available for Calprotectin:
One is based in the UK (Birmingham NEQAS).
The others are based in Europe (Sweden EQUALIS, Germany INSTAND, Spain GECLID) and have been running for a number of years.