CALEX® Patient Pack for Home Sampling

We are pleased to announce the launch of the new patient collection kits for faecal calprotectin testing. Each kit is discretely packaged in a business style envelope with a CALEX extraction device, a patient specific instruction for use with integral label (name, DOB and sample collection date) and a clear grip seal bag for return of the CALEX and the request form back to the laboratory or GP as currently with the existing stool pot method.

The IFU is written in lay terms and has guidance on taking the sample, simple to follow instructions with diagrams and a link to a video to support the correct usage of the CALEX with different sample consistencies.

The kits come in boxes of 20 and are stored at ambient until the expiry stated which is generally 12 – 18 months, so that they can be sent out to clinics and primary care in quantities and conditions that will minimise wastage. The boxes have a dispensing tally on the front to help maintain the correct level of stock within individual locations. Hospitals can either order the kits through Alpha laboratories and send to clinics and primary care using their existing van delivery/sample collection services, or can have the boxes sent directly to individual locations using The Alpha Portal.

One challenge in calprotectin testing arises from the varying rates of degradation within stool samples. This variability is highlighted in a stability study discussed in a 2014 paper by Lasson (Journal of Crohn’s & Colitis), revealing significant differences in degradation rates among individual samples. Although the widely accepted premise is that calprotectin remains stable in a stool sample at ambient conditions for three days, the study’s data indicates that while some samples exhibit relative stability, others experience a loss of 30 – 50% of detectable calprotectin within that time frame.

Once the sample is placed in the CALEX, it remains stable at ambient conditions for 7 days. This extended stability period allows ample time for patients to return their samples to the laboratory, mitigating the variable degradation observed in raw stool samples and facilitating more reliable reporting.

For laboratories choosing not to conduct immediate testing upon CALEX receipt, the sample retains stability for up to 15 days when stored at 2-8°C. By using the CALEX, laboratories can achieve greater result consistency and operational flexibility. This approach empowers labs to operate according to their preferred methods rather than being constrained by the stability limitations of the assay.

The result obtained from the patient using the CALEX may differ from sending in a stool sample to the lab for extraction. Similar variations have been noted with the IBDoc calprotectin home test for IBD-positive patients in comparison to lab results. Notably, calprotectin levels tend to be generally higher in patient-prepared samples than in lab-prepared samples.

This expected discrepancy is also evident with the CALEX, as demonstrated in a study by H. Bruce et al (Annuals of Clinical Biochemistry 2023), titled “Comparison of faecal calprotectin using two collection & extraction strategies for the BUHLMANN CALEX cap.”

This highlights the impact of the immediate stabilisation of the calprotectin in the buffer compared to the variable degradation of the calprotectin in a stool pot whilst in transit to the lab.

However, the general interpretation doesn’t alter greatly as is shown in the table below from the same publication: