Products for Calprotectin Extraction

CALEX Cap comparison to Gold Standard

When testing for intestinal inflammation the best sample to use is stool, as this has been in contact with the with the walls of the intestine throughout its journey and so will have collected any calprotectin that they be present. The challenge is to get the calprotectin from the stool sample into a format where it can be tested by the various assays. Weighing the sample is still considered the Gold-Standard practice for calprotectin extraction. You can read more about the weighing extraction procedure here.

The BÜHLMANN fCAL assays all use the same buffer to extract and stabilise the protein – this can either be performed using traditional manual weighing techniques, or with the assistance of extraction devices to make the process simpler and quicker e.g. The Smart-Prep device or the CALEX®.

The extraction method of choice for the BÜHLMANN fCAL assay is the CALEX®.


Track CALEX Cap
CALEX Cap Stool Extraction Device

CALEX® Cap is a stool extraction device containing a measured amount of BÜHLMANN calprotectin extraction buffer. It is for exclusive use with all BÜHLMANN calprotectin assays and  the fPELA Assay For Faecal Pancreatic Elastase.

The features of the CALEX extraction device are unique in the market. It improves laboratory workflow and efficiency by eliminating the need for sample weighing, pipetting or decanting and enabling direct loading of the extraction device onto ELISA processors and clinical chemistry analysers.

  • Ease of use for laboratory personnel and patients
  • Application as a primary tube for DS2 ELISA robots and many clinical chemistry analysers
  • An optimised sample dilution for maximum efficiency in stool extraction
  • Extract stability of 7 days at room temperature allowing batching to suit the laboratory routine
  • Very high correlation to the gold standard weighing extraction method

CALEX Cap can be used directly with:

Laboratories using CALEX Cap can benefit from the new BÜHLMANN Calprotectin ELISA kit format EK-CAL2-WEX, that is provided without extraction buffer and so reduces cost and waste.

Extended Stability of Calprotectin in CALEX

BÜHLMANN has announced the extension of the stability of calprotectin in CALEX:

Temperature Old Recommendation New Recommendation
Ambient 3 Days 7 Days
2-8C 6 Days 15 Days
-20C At least 23 months At least 23 months

Fully Automated Calprotectin Testing is Here!

The CALEX® Cap from BÜHLMANN already eased the sample preparation challenges, providing rapid, clean and consistent preparation, offering a simplified workflow solution for faecal calprotectin extraction without the need to decant or further dilute samples.

Now modifications to the blue and white caps at either end of the CALEX device, enable them to be used on laboratory track systems for a truly automated hands off approach to faecal calprotectin testing.

The white cap has been rounded so that once the stool has been sampled the CALEX can fit easily into the racks and pucks of laboratory track systems for front loading or full random access mode. The CALEX is then automatically identified from the barcode and centrifuged. The modification to the blue cap enable automated de-capping after which the CALEX is transported on the track to the appropriate analyser for the calprotectin analysis using the BÜHLMANN fCAL turbo before being moved to the automatic sealer and storage area. Results are then automatically reported on the laboratory LIM system.

Combined with the speed of result and wide assay range (20 – 8000µg/g) of the BÜHLMANN fCAL turbo, the new Track CALEX truly revolutionises the approach to Calprotectin testing.

Buhlmann Track Video_Barcode Scan
CALEX cap on Track






CALEX® Cap Videos

Watch the BÜHLMANN CALEX® Cap Extraction Tutorial

BÜHLMANN CALEX® Cap Demonstration

Watch the Track CALEX Cap Video

CALEX® Cap for Home Collection

Although calprotectin testing has significantly increased since the publication of the NICE guidelines in 2013 it was still identified in a report in 2018 from BIVDA and Innovate UK as one of three tests which if implemented fully could save the NHS £6.9 billion over a 5 year period (troponin for suspected heart attack patients, PGF for pre-eclampsia and calprotectin for screening the IBD patients from the IBS). The calprotectin element to this was estimated to be £65 million and this is just the estimated saving from wider screening; the potential financial savings to be gained from monitoring IBD positive patients could be even higher. With the existing increase in testing volume and the potential increases still to come, laboratories are looking at ways to streamline the service. Since the sample extraction, although significantly easier with the CALEX, this is still the rate limiting step for the analysis, this is where efforts are being focused.

With the simple process, ambient storage, post extraction stability and the 95 kPa postal and UN3373 and IATA 650 air freight compliance, the CALEX is suitable for extraction by the patient saving valuable laboratory resource. By loading the stool sample straight into the CALEX, it immediately stabilises the calprotectin within the buffer minimising the variable element of degradation during transit which will provide more consistent result.

“Calex® was easy to use, reduced staff time, used fewer consumables (such as inoculation loops and centrifugation tubes) and improved health and safety by avoiding further direct contact with the specimen after initial sampling.”

“Calex® devices are fit for purpose, easy to use and offer a quicker extraction process compared with manual weighing and will therefore enable increasing demands of a faecal calprotectin service.”

CALEX® Cap Sample Collection Kit from Alpha Laboratories

We are excited to introduce our latest innovation: the newly launched patient collection kits designed for faecal calprotectin testing.

Each kit comes discreetly packaged in a business-style envelope and includes a CALEX extraction device, personalised instructions, integral labels (including name, date of birth, and sample collection date), and a transparent grip-seal bag for the convenient return of both the CALEX and the request form back to the laboratory or GP.

Find out more

BÜHLMANN CALEX® Cap Collection Set

The BÜHLMANN CALEX® Cap is the first and only stool extraction device certified for safe air and road transportation according to IATA 650 (UN3373) regulations. This means it can be safely mailed from a patient’s home.

Buy the Collection Set Online

The CE Marked BÜHLMANN Feacal Extraction Home Kit allows for a quality ready extracted sample for the laboratory, and revolutionises the workflow of stool testing in terms of speed, efficiency and cost savings.

The simple to use patient kit includes a buffer filled CALEX® Cap tube containing viricide and bactericide components, stool collection sheets, a user guide and plastic bag with patient label. The sample in the CALEX can be used for analysis of both faecal calprotectin and elastase.


Comparison of faecal calprotectin using two collection and extraction strategies for the BÜHLMANN CALEX® Cap – possible implications for clinical cut-offs?
Bruce et al 2023 Annals of Clinical Biochemistry 2023, Vol. 0(0) 1–7

Key Literature