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 μl plasma, 30 minutes incubation), PCT levels were categorized into four groups (< 0.5 μg/l; ≥ 0.5−< 2 μg/l; ≥ 2−< 10 μg/l; ≥ 10 μg/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® 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®PCT, 24.5% were read within the next lower or higher category. Using a ± 10% range at the reference concentrations (20% at 0.5 μg/l), 82.7% of samples were correctly categorized and 16.4% within the next categories. Using a cut-off value of 2.0 μg/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.
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