Accuracy, precision, and consistency of methods for pathogen-specific cerebrospinal fluid/serum Q-value calculation

Osterman, Andreas; Boehm, Stephan und Osterman, Peter (2020): Accuracy, precision, and consistency of methods for pathogen-specific cerebrospinal fluid/serum Q-value calculation. In: Journal of Immunological Methods, Bd. 477, 112691

Abstract

For a CSF/serum samples pair the specific Q-value is the ratio of antibody concentrations and proportional to the pathogen-specific antibody index. It is usually extracted from optical density (OD) measurements by applying appropriate evaluation methods. Six different methods for Q-value determination, partly using parameter variation, were assessed with respect to accuracy, precision, and the methods' parameter consistency. The methods are based on the Four Parameters Logistic (4PL) equation or the a-method;one method is a polygonal line composed of calibration data. We tested on OD data of 51 CSF/serum sample pairs, measured with EUROIMMUN AG (Lubeck, Germany) ELISA tests for antibody determination in CSF, as part of INSTAND e.V. proficiency survey tests for the MRZH reaction (Measles, Rubella, Varicella zoster, Herpes simplex virus). Each method was tested with four ODs, standard curve methods additionally with only two ODs, identified by a selection rule. We found all methods to be of comparable accuracy and precision. With the standard curve methods, there were no differences between two ODs and four ODs evaluations. Consistency between method parameters and measured OD values is a key property of standard curve methods with a strong impact on accuracy and precision. We found a statistically significant difference with parameter consistency between a 4PL standard curve evaluation of this study and an a-method evaluation of data, measured with ELISAs of Siemens Healthcare GmbH (Marburg, Germany). General considerations show Q-values obtained by parameter variation to be more reliable than those resulting from selection rule application with standard curves.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0022-1759
• Sprache: Englisch