Problems of quantitative urine analysis
Kohse, K.P.; Wisser, H.
Annales de Biologie Clinique 45(6): 630-641
1987
ISSN/ISBN: 0003-3898 PMID: 3326435 Document Number: 288201
Quantitative determinations of various analytes in urine represent only a small part of all analyses performed in the routine clinical chemistry laboratory. Consequently, analytical as well as pre-analytical problems are less often considered in urine analysis. In the first part of this paper, pre-analytical factors affecting quantitative determinations are discussed, e.g., physical activity, posture, circadian rhythms, different solubilities of the various substances, errors in urine collecting, or drug effects. Subsequently, aspects of linearity and specificity of the routine determinations will be illustrated with special consideration given to protein, calcium, and enzyme determinations as well as some specialized measurements, e.g., porphyrins, catecholamines and their metabolites, or 5-hydroxyindole-acetic acid. Effects of pre-analytical and analytical factors on intra-assay and between-assay variations found in urine analysis are discussed. Using the results of surveys, it is shown that the standardization of methods as well as the use of suitable standards are mandatory for an effective amelioration of the present quality of quantitative urine analysis.