The Comparison of the Point-of-Care Serum Procalcitonin Assay Method with the BRAHMS Certified Method

Ali Volkan  Ozdemir; Soycan  Mizrak; Arzu Etem  Akaağaç

doi:10.18502/ijml.v9i2.10020

Ali Volkan Ozdemir Usak Training and Research Hospital, Department of Clinical Biochemistry Laboratory, Usak, Turkey
Soycan Mizrak Usak University, Faculty of Medicine, Department of Medical Biochemistry, Usak, Turkey
Arzu Etem Akaağaç Usak Training and Research Hospital, Department of Clinical Biochemistry Laboratory, Usak, Turkey

DOI: https://doi.org/10.18502/ijml.v9i2.10020

Keywords: Comparative assay, Human serum, Procalcitonin

Abstract

Background and Aims: As a method for the diagnosis and management of sepsis, the serum procalcitonin assay is routinely used, especially in the emergency department (ED) and intensive care units (ICU). Procalcitonin has reasonable diagnostic accuracy for bacteremia in hospitalized patients of all age groups with suspected infection or sepsis. This study aimed to compare the Getein Biotech procalcitonin point of care method with the ADVIA Centaur^® BRAHMS serum procalcitonin method.

Materials and Methods: Linearity,recovery, accuracy, and imprecision studies were carried out to evaluate the analytical performance. Bland-Altman plots and Passing-Bablok regression analysis were used to compare patient results. The Kappa test assessed the concordance between the results at cut-off levels of 0.5ng/mL and 2.0ng/mL.

Results: In the linearity study performed by obtaining serial dilutions from high and low-level serum pools, the regression equations were "y=-0.03(-0.07 to 0.05)+1.01(0.7 to 1.08)x" and "y=0.463(-1.16 to 2.01)+0.912(0.72 to 1.04)x" respectively. There is no deviation from linearity with the Cusum test (p=0.99 and 0.57). Average recovery value:86%. The CV% values of Control Level-1,2 were 3.75% and 4.2%. 0.1-50.0ng/ml range shows deviation from linearity determined by Cusum test (p=0.01). There was no deviation from linearity in the range of 0.1-2.0ng/ml (p=0.42). Kappa values were calculated as 0.864 and 0.800 (p<0.001).

Conclusions: Getein1600 Procalcitonin test should be used for triage or screening purposes. However, a high constant error and deviation from linearity detected at high concentrations indicate that this test should not be used to initiate an antibiotic therapy or alter the current therapy course.