Clinical experiences with a new semi-quantitative solid phase immunoassay for rapid measurement of procalcitonin

A self-developing solid-phase immunoassay (B.R.A.H.M.S. PCT-Q, B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany) has recently become available for the semi-quantitative and rapid measurement of procalcitonin (PCT). In this study we examined the validity of this assay at daily clinical routine conditions at five different hospitals in a prospective study. After development of the assay (200 mul plasma, 30 minutes incubation). PCT levels were categorized into four groups (< 0.5 <mu>g/l; greater than or equal to 0.5-< 2 ug/l; <greater than or equal to> 2-< 10 <mu>g/l; greater than or equal to 10 ug/l) according to the provided reference scale. Samples from patients with suspected elevation of PCT of different etiology (n=237) were read by various analyzers and compared with the results of the Lumitest(R) PCT (B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany). A total of 74.7% of measurements were categorized according to the results of the Lumitest(R)PCT, 24.5% were reed within the next lower or higher category. Using a +/- 10% range at the reference concentrations (20% at 0.5 mug/l). 82.7% of samples were correctly categorized and 16.4% within the next categories. Using a cut-off value of 2.0 mug/l. 92.0% (94.1% for +/- 10%) of the results were correctly categorized. The semi-quantitative solid phase immunoassay allows a rapid, simple and semi-quantitative measurement of plasma PCT. The validity of the test results and its ease of use are sufficient to support acute diagnostic decisions. However, for the follow-up of PCT concentrations and routine daily measurements, the quantitative luminometric assay should be preferred, when available.