[Influence and analysis of seven kinds of hemoglobin variants on HbA1c detection].

OBJECTIVE: To explore the effects of seven kinds of hemoglobin variants on two HbA1c detection methods. METHODS: Twenty-five hemoglobin variant samples (Hb D, S, Q, G, J, E & F) and 40 control samples were from February 2012 to April 2013 collected. All samples were tested by ion exchange-high performance liquid chromatography system (IE-HPLC) and affinity chromatograghy high performance liquid chromatography (AC-HPLC) respectively.We compared the coincidence between HbA1c results of two instruments and blood glucose and observed the difference between variant and control groups for two methods using statistic software SPSS 19.0. RESULTS: A high consistency existed between IE-HPLC and AC-HPLC in the control group with no hemoglobin variants (6.68% ± 1.87% vs 6.64% ± 1.99%, P > 0.05) . For the hemoglobin variants group, the results of HbA1c via IE-HPLC were interfered by hemoglobin variants (3.57% ± 3.51% than 4.95% ± 0.57%, P < 0.05). However, HbA1c detection of AC-HPLC had no interference with hemoglobin variants and it demonstrated an excellent correlation with blood glucose. CONCLUSIONS: The results of HbA1c in blood samples containing common hemoglobin variants may be interfered on IE-HPLC to be falsely lower or higher.Only detecting glycated hemoglobin with strong specificity,AC-HPLC is well-correlated with blood glucose and its results are not interfered by common variant hemoglobin.

Biological variations of thirteen plasma biochemical indicators.

BACKGROUND: Reports on biological variation of plasma biochemical indicators are limited. We evaluated biological variations of 13 plasma biochemical indicators. METHODS: Plasma samples were collected from 40 healthy individuals over 5days. Intra-individual coefficient of variation (CVI), inter-individual coefficient of variation (CVG), index of individuality (II), reference change value (RCV), and analytical goal parameters were calculated. RESULTS: Albumin (Alb) showed the lowest CVI (2.50%) and the lowest CVG (5.08%), while C-reactive protein (hsCRP) presented the highest CVI (26.87%) and CVG (61.73%). II values were all less than 1.0. Alb presented the lowest 95% RCV (7.67), while hsCRP showed the highest 95% RCV (74.61). Alb, urea, creatinine (Cr), creatine kinase (CK), and creatine kinase isoenzyme MB (CKMBmass) CVI differed with gender (P<0.05). The CVG of the 13 indicators presented a significant gender difference (P<0.0001). Alb showed the lowest desirable imprecision CV (1.3%), the lowest desirable bias (1.4%), and the lowest desirable total error (3.5%), while hsCRP presented the highest desirable imprecision (13.4%), the highest desirable bias (16.8%), and the highest desirable total error (39.0%). CONCLUSION: Our findings add to the database of biological variations of plasma indicators.

Strong Negative Interference by Calcium Dobesilate in Sarcosine Oxidase Assays for Serum Creatinine Involving the Trinder Reaction.

The vasoprotective drug calcium dobesilate is known to interfere with creatinine (Cr) quantifications in sarcosine oxidase enzymatic (SOE) assays. The aim of this study was to investigate this interference in 8 different commercially available assays and to determine its clinical significance. In in vitro experiments, interference was evaluated at 3 Cr levels. For this, Cr was quantified by SOE assays in pooled serum supplemented with calcium dobesilate at final concentrations of 0, 2, 4, 8, 16, 32, and 64 µg/mL. Percent bias was calculated relative to the drug-free specimen. For in vivo analyses, changes in serum concentrations of Cr, cystatin C (CysC; a renal function marker), and calcium dobesilate were monitored in healthy participants of group I before and after oral calcium dobesilate administration. In addition, variations in interference were also examined among different SOE assays using serum obtained from healthy participants of group II. Lastly, Cr levels from the 10 patients treated with calcium dobesilate were measured using 4 SOE assays and liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) for comparison. Our in vitro analyses indicated that the presence of 8 µg/mL calcium dobesilate resulted in a -4.4% to -36.3% reduction in Cr serum concentration compared to drug-free serum for 8 SOE assays examined. In vivo, Cr values decreased relative to the baseline level with increasing drug concentration, with the lowest Cr levels obtained at 2 or 3 hours after drug administration in participants of group I. The observed Cr concentrations for participants in group II were reduced by -28.5% to -3.1% and -60.5% to -11.6% at 0 and 2 hours after administration related to baseline levels. The Cr values of 10 patients measured by Roche, Beckman, Maker, and Merit Choice SOE assays showed an average deviation of -20.0%, -22.4%, -14.2%, and -29.6%, respectively, compared to values obtained by LC-IDMS/MS. These results revealed a clinically significant negative interference with calcium dobesilate in all sarcosine oxidase-based Cr assays, but the degree of interference varied greatly among the assays examined. Thus, extra care should be taken in evaluating Cr quantification obtained by SOE assays in patients undergoing calcium dobesilate therapy.