Components of total measurement error for hemoglobin A(1c) determination.

Oxidation of nitric oxide in aqueous solution to nitrite but not nitrate: comparison with enzymatically formed nitric oxide from L-arginine. A spectrophotometric assay for nitrate using NADPH oxidation by Aspergillus nitrate reductase. Measurement of nitrite and nitrate in biological fluids by gas chromatography mass spectrometry and by the Griess assay: problems with the Griess assay—solutions by gas chromatography–mass spectrometry. Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(III) reduction with chemiluminescence detection. Nitric oxide synthase from cerebellum catalyzes the formation of equimolar quantities of nitric oxide and citrulline from L-arginine. oxide production and hepatic dysfunction in patients with postoperative sepsis. al. Systemic inflammatory response syndrome and acute renal failure associated with Hemophilus influenzae septic meningitis. al. Bacillus cereus causing fulminant sepsis and hemolysis in two patients with acute leukemia. Clostridial sepsis with massive intravascular hemolysis: rapid diagnosis and successful treatment. Clostridium perfringens septicemia with massive hemolysis in a patient with Hodgkin's lymphoma. et al. Effects of reducing reagents and temperature on conversion of nitrite and nitrate to nitric oxide and detection of NO by chemiluminescence. The Diabetes Control and Complications Trial (DCCT) and the UK Prospective Diabetes Study (UKPDS), under-taken in people with type 1 and 2 diabetes, respectively (1, 2), established the significance of glycohemoglobin (gHb), and in particular hemoglobin A 1c (HbA 1c), as a prognostic indicator for long-term micro-and macrovas-cular complications. However, the HbA 1c measured during the DCCT and UKPDS represents a gHb fraction characterized by its retention time on cation-exchange HPLC rather than its unique chemical structure (deoxy-fructosylhemoglobin). Accordingly, the DCCT HbA 1c procedure represents a selective, but not a specific assay method (3). Because no definitive or reference method exists for quantification of HbA 1c (4), the American Diabetes Association (ADA), in collaboration with the Association of Clinical Chemists, implemented the National Glycohemo-globin Standardization Program (NGSP) (5) to standardize HbA 1c values determined by methods different from that used in the DCCT. The ADA (6) now states that their recommended HbA 1c thresholds, with respect to patient management goals, are valid only for NGSP-certified methods. The variability of HbA 1c measurements depends on both analytical and biological variation. However, because HbA 1c concentrations are used for individual patient management, only analytical imprecision and within person biological variation (s i 2) are relevant. Whereas the NGSP (5) states that within-person HbA 1c variance is negligible, previous studies (7, 8) have reported s …