Application of quality control planning methods for the improvement of a quantitative molecular assay.

Hepatitis B virus (HBV) DNA measurement has an important role in the diagnosis and management of patients with chronic HBV infection. In cases of chronic hepatitis B, clinical decision is based on either the absolute amount of HBV DNA level, or else the relative change in HBV DNA level. To produce high quality and comparable results, assay performance characteristics must be verified and statistical quality control methods must be planned. In this study, systematic and random error values in an assay of plasma HBV DNA were determined. Performance of the method was examined by employing a normalized operational process specifications (OPSpecs) chart. The systematic error at low and high control levels were 0.33 and 0.22 log(IU/mL) respectively. At both levels, the standard deviations (SD) of the assay were 0.17 log(IU/mL). In addition, a single rule of 12.5SD with 2 control measurements was selected as a candidate quality control method. The assay performed well and was acceptable for clinical use. Further improvement may be attained by switching to automated purification methods. In this study, the well-established discipline of statistical quality control was applied to a real-time quantitative PCR. It was concluded that by employing statistical quality control (QC) methods, which utilize long-term controls, critical changes in the measurement system could be detected.

Correlation between Plasma Adiponectin Levels and the Presence and Severity of Coronary Artery Disease.

BACKGROUND: The existing evidence suggests that plasma adiponectin concentrations can be indicative of the presence and severity of coronary artery disease (CAD). However, the results of the studies conducted hitherto on this subject are inconsistent. We sought to investigate the possible correlation between plasma adiponectin levels and the presence and severity of CAD in patients undergoing non-urgent coronary angiography. METHODS: In 399 consecutive patients undergoing non-urgent coronary angiography for CAD survey, plasma adiponectin, triglyceride, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol, and fasting blood sugar levels were measured and demographic characteristics such as age, sex, Body Mass Index, diabetes mellitus history, systemic hypertension history, and family history of CAD were collected. According to the angiography results, the patients were divided into two groups of CAD and non-CAD. The severity of coronary atherosclerosis in the CAD group was defined using the Gensini score system. RESULTS: Average age was 61.4 ± 9.94 years in the CAD group and 57.9 ± 10.75 years in the non-CAD group. Also, 73.7% of the CAD group and 55.4% of the non-CAD group were male. Totally, 278 (69.7%) patients were found to have CAD. Patients without CAD did not have higher mean plasma adiponectin concentrations than did those with CAD (13.38 ± 11.96 vs. 14.95 ± 14.11 mcg/ml; p value = 0. 896). After adjustment for CAD conventional risk factors, plasma adiponectin levels still were not associated with CAD. No association was found between plasma adiponectin levels and the Gensini score. Furthermore, in contrast to the fairly strong correlation previously reported, there was no correlation between adiponectin levels and conventional CAD risk factors. CONCLUSION: We could not observe any relationship between plasma adiponectin concentrations and the presence or severity of CAD in patients undergoing coronary angiography.

Sodium bicarbonate plus isotonic saline versus saline for prevention of contrast-induced nephropathy in patients undergoing coronary angiography: a randomized controlled trial.

BACKGROUND: There is controversy about the prophylactic measures proposed for the prevention of contrast-induced nephropathy (CIN). We aim to compare the efficacy of the combination of sodium bicarbonate and isotonic saline and that of isotonic saline alone in preventing CIN. STUDY DESIGN: Randomized double-blind controlled trial. SETTING & PARTICIPANTS: 265 consecutive patients 18 years or older with a serum creatinine level of 1.5 mg/dL or greater undergoing elective coronary angiography from August 2007 to June 2008 in Tehran Heart Center, Tehran, Iran. INTERVENTION: Study participants were randomly assigned to receive either 75 mL of 8.4% sodium bicarbonate added to 1 L of isotonic saline (n = 135) or isotonic saline alone (n = 130) as a bolus of 3 mL/kg for 1 hour before contrast injection, followed by an infusion of 1 mL/kg/h for 6 hours after the procedure. OUTCOMES & MEASUREMENTS: The primary end point was an absolute (>or=0.5 mg/dL) or relative (>or=25%) increase in serum creatinine level 48 hours after the procedure (CIN). RESULTS: There were no significant differences between the bicarbonate and saline groups regarding baseline demographic and biochemical characteristics, including baseline serum creatinine level (1.63 +/- 0.32 [SD] versus 1.66 +/- 0.50 mg/dL), baseline glomerular filtration rate (46.4 +/- 12 versus 45.4 +/- 12 mL/min/1.73 m(2)), and baseline urine pH (5.42 +/- 0.6 versus 5.46 +/- 0.8). Nine patients (7.4%) receiving sodium bicarbonate developed CIN as opposed to 7 patients (5.9%) in the saline group, which was not statistically different (odds ratio, 1.26; 95% confidence interval, 0.45 to 3.50; P = 0.6). LIMITATIONS: The trial did not follow up participants to assess need for dialysis and mortality rate. CONCLUSION: The combination therapy of sodium bicarbonate plus saline does not offer additional benefits over hydration with saline alone in the prevention of CIN.

The relationship between level of androgenic hormones and coronary artery disease in men.

BACKGROUND: Previous studies have shown controversial results on the role of androgens in coronary artery disease (CAD). We performed this study to assess the relationship between androgen levels and selective coronary angiography (SCA) findings. METHODS: This study was conducted on 502 consecutive men who underwent SCA with different indications in our centre. Medical history and blood samples were taken from all subjects prior to angiography. Free testosterone (FREET) was measured with enzyme-linked immunosorbent assay, and total testosterone (TES) plus dehydroepiandrosterone sulfate (DHEA) were checked with radio-immunoassay. Total cholesterol, high- and low-density lipoprotein cholesterol (HDL and LDL), triglycerides, lipoprotein (a) [Lp(a)] and C-reactive protein (CRP) were also tested in all patients. Angiographic results were reported by two cardiologists and checked for intra- and inter-observer reliability, then interpreted as Gensini score, and on the basis of the number of segments involved. The relationships were assessed with the chi-square test, independent sample t-test, one-way analysis of variances, Pearson's correlation, and univariate and multivariate logistic regression tests. RESULTS: Eighty-three (16.5%) of the subjects had single-vessel disease, 108 (21.5%) had two-vesssel, 197 (39.2%) had three-vessel disease, and 114 (22.7%) had normal angiograms or minimal lesions. FREET, TES and DHEA in patients with significant CAD vs normal individuals were 6.69 +/- 3.20 pg/ml, 16.60 +/- 6.66 nm/l and 113.38 +/- 72.9 microg/dl vs 7.12 +/- 3.58 pg/ml, 15.82 +/- 7.26 nm/l and 109.03 +/- 68.19 microg/ dl, respectively (p > 0.1). There was no correlation between the Gensini score or the number of involved segments and androgen levels. Triglyceride, total cholesterol, LDL and HDL cholesterol levels also had no correlation with androgenic hormones. However, FREET showed a negative correlation with Lp(a) and CRP (p = 0.01, r = -0.12; p = 0.03, r = -0.096, respectively). Moreover, the level of DHEA was lower in diabetics (94.5 +/- 59.19 microg/dl vs 117.97 +/- 74.54 microg/dl, p = 0.004). CONCLUSIONS: There was no significant correlation between FREET, TES, DHEA and the presence or severity of CAD. Also, no correlation was found between androgen levels and triglyceride, total cholesterol, LDL and HDL cholesterol levels.