title: Diagnostic performance of red cell sorbitol assay in a Nigerian teaching hospital.
abstract: The analytical linearity, detection limit, precision and accuracy, as well as diagnostic sensitivity, specificity and predictive values of red cell sorbitol (RCS) assay were evaluated using the fluorimetric enzymatic technique with the available laboratory facilities in a Nigerian Teaching Hospital. The assay was linear up to 40.0 nmol/ml. The detection limit was 0.55 nmol/ml. The within-assay coefficients of variation (CV) from low to high concentrations were in the range of 2.82% to 5.48% while the corresponding values for the between-assay variation were 3.60% to 6.05%. The mean recovery was 90.4%. High concentrations of some common blood constituents and drugs did not cause significant interference. An evaluation of the diagnostic sensitivity and specificity of RCS in 102 out-patients revealed a sensitivity of 94.4%, specificity of 98.8% and efficiency of 98.0%. The predictive value of a positive test was 94.4% while that of a negative test was 98.8%. The mean value of red cell sorbitol in patients confirmed to have diabetes mellitus (23.1 +/- 1.13 SE nmol/g Hb) was significantly higher (P < 0.001) than the corresponding value (11.0 +/- 0.0.27 SE nmol/g Hb) for those without diabetes and for control subject. A similar observation was also made for plasma glucose and fructosamine. These observations demonstrate that RCS assay could be adopted in a third world laboratory for clinical applications.
authors.affiliation: Department of Chemical Pathology, Ahmudu Bello University Teaching Hospital, Zaria, Nigeria.
authors.forename: H P
authors.initials: HP
authors.lastname: Anaja
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D016001:Confidence Intervals; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis; D004789:Enzyme Activation; D004912:Erythrocytes / Q000737:chemistry* / Q000201:enzymology; D005260:Female; D006801:Humans; D007064:L-Iditol 2-Dehydrogenase / Q000592:standards; D008297:Male; D008875:Middle Aged; D009549:Nigeria; D012016:Reference Values; D012680:Sensitivity and Specificity; D013012:Sorbitol / Q000097:blood*; D013050:Spectrometry, Fluorescence / Q000592:standards
chemical_list: D001786:Blood Glucose; D013012:Sorbitol; D007064:L-Iditol 2-Dehydrogenase