Evaluation of enzymatic method for determination of serum beta-hydroxybutyrate and its clinical application / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate an enzymatic method for determining serum beta-hydroxybutyrate (beta-HB) with the National Committee for Clinical Laboratory Standards (NCCLS) projects, and to discuss its clinical values in diabetic ketoacidosis (DKA).</p><p><b>METHODS</b>The precision, accuracy, specificity, linearity and interference of the enzymatic method were analyzed. This method was used to determine serum beta-HB in 60 cases of normals, 50 cases of diabetes, and 34 cases of DKA by autochemistry analyzer.</p><p><b>RESULTS</b>Enzymatic beta-HB assay was precise (within-run CV, day-to-day CV, and total CV < 5%). The linearity studies showed the method was linear up to 4 mmol/L. Recovery rate was 98.5%-104.1%. Hemolysis (Hemoglobin up to 18.2 g/L), icteric samples with total bilirubin up to 224 mumol/L, and lipemia up to triglyceride concentration of 2.28 mmol/L did not interfere with the beta-HB results in this method. Serum beta-HB levels were significantly elevated in DKA patients compared with DM patients and controls (P < 0.01). Positive rate of serum beta-HB in DKA patients was significantly higher than that of urinary ketone (P < 0.05).</p><p><b>CONCLUSIONS</b>Enzymatic method is convenient and reliable, allows full automation, and is rapid enough to be used for both routine and urgent determinations of serum beta-HB. It can be used in diagnosing and monitoring treatment of DKA.</p>

Clinical evaluation of two kinds homogenous assays for determination of high-density lipoprotein cholesterol / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the clinical efficacy of two kinds homogenous assays for direct determination of high-density lipoprotein cholesterol (HDL-C) based on the principle of polyanion polymer/detergent (PPD method) and polyethylene glycol-modified enzyme (PEGME) method.</p><p><b>METHODS</b>The two homogenous methods were compared with the precipitation method (PTA-Mg2+ method), their precision, accuracy, specificity and interference were also analyzed.</p><p><b>RESULTS</b>Both homogenous HDL-C assays were precise, having a within-run CV < 3%, day-to-day CV < 3% and total CV < 4%. The HDL-C values measured by the two homogenous methods correlated well with those by PTA-Mg2+ method (X): Y = 0.9316 X + 0.1063, r = 0.9762 for PPD method (Y); and Y = 0.9106 X + 0.1368, r = 0.9894 for PEGME method (Y). The linearity studies showed the two homogenous methods to be linear up to 4.14 mmol/L. The lowest detectable concentration of the two methods was apparently 0.08 mmol/L. Recoveries of the two methods were 94.1%-106.2%. Hemoglobin did not interfere with the HDL-C results in the two homogenous methods, whereas icteric samples with total bilirubin > 200 mg/L showed discrepancies. Lipemia up to triglyceride concentration of 17.0 mmol/L did not interfere with the two homogenous HDL-C assays.</p><p><b>CONCLUSIONS</b>The two new homogenous HDL-C assays meet the requirements for accuracy, precision, ease of handling with massive sample, allow full automation, and are clinically useful.</p>