Those laboratories initially using a lower throughput system for calprotectin measurement,such as the BÜHLMANN Quantum Blue kit, may find they need to transfer to a more cost and time-effective automated, higher-throughput system.
When deciding which higher-throughput assay to use, it is important to consider:
- The correlation between the results obtained with lower- and higher-throughput assay formats.
- Whether the same cut-off concentration is used for the results of the assays and whether this has been validated with clinical evidence.
- If CE-marked applications are available for the automation of the high-throughput kit.
- If the high-throughput kit is in a ready-to-use, easy to order format
And last, but by no means, least:
- The analytical sensitivity, specificity, imprecision, working range and linearity
- The correlation of results with clinical findings
These are of paramount importance when deciding which calprotectin assay is to be adopted. 1, 2
In the CPA (UK) Ltd “Standards for the Medical Laboratory”, it is stated that:
‘The laboratory shall have a mechanism for ensuring that examinations performed
using different procedures or equipment or at different sites give comparable
results, in particular, throughout clinically appropriate intervals (F.3.5)’
BÜHLMANN ensures that the Quantum Blue system correlates significantly with the EK-CAL ELISA and that the entire range of calprotectin assay formats all give excellent analytical sensitivity, specificity, imprecision, working range and linearity. This means that patients initially tested using the Quantum Blue assay can be followed up using the EK-CAL kit without differences in results. Any significant difference in calprotectin concentrations seen in an individual patient will reflect a clinical change!
All assay kits in the BÜHLMANN calprotectin range are easy to use but, more importantly, use ensures that results correlate with clinical findings and are precise and linear across the working range.
CE-marked applications for the Calprotectin ELISA are available for the DS2 (available from Alpha Laboratories) and the DSx.
This article was published previously in Alpha Laboratories’ Leading Edge Newsletter – Winter 2012.
Click here to read more diagnostic articles published in Leading Edge
References:
Cut-off comparison with clinical findings
1. Manz M. et al. Value of fecal calprotectin in the evaluation of patients with abdominal discomfort: an
observational study. BMC Gastroenterology 2012, 12:5
Dilution Linearity of EK-CAL
2. Vermunt R. et al. Calprotectin in biomarker-mediated drug development: Method validation for the
quantification of fecal Calprotectin. Eurofins Poster
