Clinical biochemistry laboratory rejection rates due to various types of preanalytical errors.

INTRODUCTION: Preanalytical errors, along the process from the beginning of test requests to the admissions of the specimens to the laboratory, cause the rejection of samples. The aim of this study was to better explain the reasons of rejected samples, regarding to their rates in certain test groups in our laboratory. MATERIALS AND METHODS: This preliminary study was designed on the rejected samples in one-year period, based on the rates and types of inappropriateness. Test requests and blood samples of clinical chemistry, immunoassay, hematology, glycated hemoglobin, coagulation and erythrocyte sedimentation rate test units were evaluated. Types of inappropriateness were evaluated as follows: improperly labelled samples, hemolysed, clotted specimen, insufficient volume of specimen and total request errors. RESULTS: A total of 5,183,582 test requests from 1,035,743 blood collection tubes were considered. The total rejection rate was 0.65 %. The rejection rate of coagulation group was significantly higher (2.28%) than the other test groups (P < 0.001) including insufficient volume of specimen error rate as 1.38%. Rejection rates of hemolysis, clotted specimen and insufficient volume of sample error were found to be 8%, 24% and 34%, respectively. Total request errors, particularly, for unintelligible requests were 32% of the total for inpatients. CONCLUSIONS: The errors were especially attributable to unintelligible requests of inappropriate test requests, improperly labelled samples for inpatients and blood drawing errors especially due to insufficient volume of specimens in a coagulation test group. Further studies should be performed after corrective and preventive actions to detect a possible decrease in rejecting samples.

The anti-inflammatory and antioxidant effects of pravastatin and nebivolol in rat aorta.

OBJECTIVE: The aim of this study was to investigate the effects of pravastatin and nebivolol in the atherosclerotic process including inflammation and oxidative stress in rat aorta. METHODS: This experimental randomized controlled study comprised of 35 Wistar albino rats. Nω-nitro-L-arginine methyl ester (L-NAME) - induced vascular inflammation and arteriosclerosis were treated with both of the pharmacologic agents. All were divided into 5 equal groups: the control, group I: L-NAME -15 days, group II: L-NAME 30+ nebivolol, group III: L-NAME -30+ pravastatin, group IV: L-NAME - 30 days. Serum ceruloplasmin, uric acid, total antioxidant capacity (TAC), total cholesterol (T.Chol), low density lipoprotein (LDL), high density lipoprotein (HDL), triglyceride (TG) were analyzed. Medial thickening and leukocyte infiltration status were examined histopathologically. The results were compared with control group and with each other using Kruskal-Wallis and Mann-Whitney U test. RESULTS: Pravastatin diminished the rise of ceruloplasmin, which was taken as an index of inflammation (p=0.002). Pravastatin and nebivolol decreased the L-NAME induced oxidative stress (p=0.001, 0.002, respectively). Nebivolol diminished the rise of LDL (p=0.04). Pravastatin lowered T.Chol, LDL and TG levels (p=0.001, 0.008, 0.040, respectively). HDL values were not changed significantly. CONCLUSION: In conclusion, 15 days of statin therapy attenuated vascular inflammation and lowered the rised lipid levels (LDL, T.cholesterol and TG). Both the nebivolol and pravastatin exhibited antioxidant property. These documented beneficial effects of both of the drugs may improve the clinical outcomes of patients with hypertension or hyperlipidemia by additional studies.

The anti-inflammatory and antioxidant effects of pravastatin and nebivolol in rat aorta.

OBJECTIVE: The aim of this study was to investigate the effects of pravastatin and nebivolol in the atherosclerotic process including inflammation and oxidative stress in rat aorta. METHODS: This experimental randomized controlled study comprised of 35 Wistar albino rats. Nω-nitro-L-arginine methyl ester (L-NAME) - induced vascular inflammation and arteriosclerosis were treated with both of the pharmacologic agents. All were divided into 5 equal groups: the control, group I: L-NAME -15 days, group II: L-NAME 30+ nebivolol, group III: L-NAME -30+ pravastatin, group IV: L-NAME - 30 days. Serum ceruloplasmin, uric acid, total antioxidant capacity (TAC), total cholesterol (T.Chol), low density lipoprotein (LDL), high density lipoprotein (HDL), triglyceride (TG) were analyzed. Medial thickening and leukocyte infiltration status were examined histopathologically. The results were compared with control group and with each other using Kruskal Wallis and Mann-Whitney U test. RESULTS: Pravastatin diminished the rise of ceruloplasmin, which was taken as an index of inflammation (p=0.002). Pravastatin and nebivolol decreased the L-NAME induced oxidative stress (p =0.001, 0.002, respectively). Nebivolol diminished the rise of LDL (p=0.04). Pravastatin lowered T.Chol, LDL and TG levels (p=0.001, 0.008, 0.040, respectively). HDL values were not changed significantly. CONCLUSION: In conclusion, 15 days of statin therapy attenuated vascular inflammation and lowered the rised lipid levels (LDL, T.cholesterol and TG). Both the nebivolol and pravastatin exhibited antioxidant property. These documented beneficial effects of both of the drugs may improve the clinical outcomes of patients with hypertension or hyperlipidemia by additional studies.

Comparing the renal safety of isoosmolar versus low-osmolar contrast medium by renal biomarkers N-acetyl-ß-D-glucosaminidase and endothelin.

Iodixanol and iopamidol are commonly used contrast agents in coronary angiography. We evaluated the nephrotoxic effects of both contrast media in relation to renal biomarkers. A total of 38 low-risk patients who underwent coronary angiography were enrolled. Patients were randomized to receive either low-osmolar nonionic monomer or isoosmolar nonionic dimer contrast medium. N-Acetyl-ß-d-glucosaminidase (NAG), endothelin, blood urea nitrogen, and urine and serum creatinine (SCr) levels were measured before  the procedure (T0), at 6 hours (T6), and at 1 year after the procedure. Plasma endothelin, urine NAG/creatinine, and SCr were higher; accordingly, the urine creatinine values were lower in both the groups when comparing T0 versus T6. The groups were similar with each other when comparing T0 and T6 values. Both the contrast agents may be safely used at a low volume for coronary angiography in low-risk patients. Endothelin and NAG are sensitive to acute renal changes in function. There is a need for further prospective investigations with more patients.

Plasma leptin values in postmenopausal women with osteoporosis.

Obesity has a protective effect against osteoporosis and this effect has been attributed to a high body fat content. It has been shown that the leptin concentration is higher in obese patients. Leptin, the protein product of obesity gene, is a hormone produced in adipose tissue. Some studies suggest that endogenous leptin might influence bone metabolism in postmenopausal women. In this study, we investigated plasma leptin concentrations in postmenopausal women with osteoporosis and also analyzed the relationship between plasma leptin levels and bone mineral density (BMD) in order to understand the potential role of leptin in maintaining bone mass. Forty-two postmenopausal women with osteoporosis and thirty seven age and BMI-matched healthy postmenopausal women were included in the study. The mean femoral neck BMD value in the patient group was significantly lower than that in the control group (0.691±0.1 g/cm2 and 0.863±0.1 g/cm2, respectively; p<0.001). The mean plasma leptin concentration in the patient group was not significantly different from that in the control group (p>0.05). Plasma leptin levels were correlated with BMI in both groups (p<0.001 in the patient group and p=0.001 in controls). There was also a strong positive correlation between plasma leptin levels and %fat in both groups (p<0.001 in the patient group and p<0.001 in controls). But there was no correlation between plasma leptin levels and femoral neck BMD values in both groups. Our results do not support the hypothesis that leptin itself plays an important role in maintaining bone mass in postmenopausal women.

Prognostic significance of circulating tumor cells and serum CA15-3 levels in metastatic breast cancer, single center experience, preliminary results.

BACKGROUND: Breast cancer is the second leading cancer causing death in women. Circulating tumor cells are among the prognostic factors while tumor markers are of diagnostic value and can be used for follow-up. The aim of this study was to investigate the correlation between the prognostic significance of the serum CA15-3 levels, number of circulating tumor cells and histopathological tumor factors. MATERIALS AND METHODS: Thirty patients recently diagnosed with breast cancer were included in the study. Number of circulating tumor cells and serum CA15-3 level were assessed when metastasis was detected and diagnostic value was assessed. Presence of associations with estrogen and progesterone receptors, c-erbB2, Ki-67 proliferation index and histological grade were also evaluated. RESULTS: Median overall survival of the patients with serum CA15-3 levels of >108 ng/dl was 19 months whereas for those with a low serum level it was 62 months. Median overall survival for CTC ≥5vs CTC<5 patients was 19 months and 40 months respectively. The difference between the two groups was statistically significant. CONCLUSIONS: Prognostic significance of the CTC count and CA15-3 levels in metastatic breast cancer patients was demonstrated.

The effect of storage time and freeze-thaw cycles on the stability of serum samples.

INTRODUCTION: Optimal storage of serum specimens in central laboratories for a long period for multicenter reference interval studies, or epidemiologic studies remains to be determined. We aimed to examine the analytical stability of chemistry analytes following numerous freeze-thaw and long-term storage. MATERIALS AND METHODS: Serum samples were obtained from 15 patients. Following baseline measurement, sera of each subject were aliquoted and stored at -20 degrees C for two experiments. A group of sera were kept frozen for up to 1, 2 and 3 months and then analyzed for stability. The other experiment consisted of one to ten times of freeze and thaw cycles. Total of 17 chemistry analytes were assayed at each time point. The results were compared with those obtained from the initial analysis of fresh samples. Median or mean changes from baseline (T(0)) concentrations were evaluated both statistically and clinically according to the desirable bias. RESULTS: Of the analytes studied, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), gamma-glutamyl transferase (GGT), direct bilirubin, glucose, creatinine, cholesterol, triglycerides, high density lipoprotein (HDL) were stable in all conditions. Blood urea nitrogen (BUN), uric acid, total protein, albumin, total bilirubin, calcium, lactate dehydrogenase (LD) were changed significantly (P < 0.005). CONCLUSIONS: As a result, common clinical chemistry analytes, with considering the variability of unstable analytes, showed adequote stability after 3 months of storage in sera at -20 degrees C, or up to ten times of freeze-thaw cycle. All the same, such analysis can only be performed for exceptional cases, and this should be taken into account while planning studies.

Cardiovascular risk factors in young male adults: impact of physical activity and parental education.

BACKGROUND: This study was conducted to assess whether choices of physical activity, smoking status, and parental education and income were correlated with the health status of young adult males which are important for preventive health policy. METHODS: 491 18-29-year old males from lower socioeconomical districts in Turkey participated in this study. Information about demographic characteristics, parental education, household income, smoking status, and physical activity was obtained by means of a standardized questionnaire. BMI and metabolic parameters (serum lipid profile) were assessed. RESULTS: Mean total cholesterol, LDL, HDL and triglyceride levels were in the normal range. The physically active group displayed a better lipid profile. No relationship was found between parental education and serum lipids. Smoking was slightly correlated with household income (r=103, p=0.022). CONCLUSION: Young adult males who participate in relatively high levels of physical activity are at lower CHD risk than less active ones. The present study also showed that lower socioecnomic status does not always correlate with higher levels of cardiovascular risk factors. In conclusion, data supports that while family history cannot be changed, HDL levels can be modulated by lifestyle factors as in other populations and that with the determined benefits of increasing physical activity and thus, HDL levels, policy reform in schools to promote physical activity are warranted.

Stability studies of common biochemical analytes in serum separator tubes with or without gel barrier subjected to various storage conditions.

INTRODUCTION: The collected and shipped blood samples are exposed to a various extra-analytical factors prior to analysis. The aim of the study was to determine the stability of analytes in serum gel tubes and plain tubes exposed to a range of storage temperatures and times after centrifugation. MATERIALS AND METHODS: Fifteen healthy volunteers were recruited and venous blood was collected into four tubes, two with and two without gel separator. Analyzing the baseline samples in 30 min, all were stored at 4 degrees C or 24 degrees C for 6, 12, 18, 24, 30, 36, 48 and 72 hours and 1 week. Sixteen biochemical anaytes were measured on each sample. Variations remained under the desirable bias considered as clinically insignificant. RESULTS: On day three, most analytes remained stable including albumin, protein, creatinine, cholesterol, triglycerides, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), creatine kinase (CK), lactate dehydrogenase (LD) regardless of tube types. Glucose concentration decreased markedly (P = 0.001) beginning from the first hours of storage in plain serum. The stability maximized for the analytes including glucose, total bilirubin, urea nitrogen (BUN), uric acid stored at 4 degrees C in gel tubes. Aspartate aminotransferase (AST) activity increased significantly (P = 0.002) up to 48-h, however bias was not significant clinically. High density lipoprotein (HDL) concentration was stable in gel tubes at 24 degrees C, in plain tubes at 4 degrees C stored up to 36-h. CONCLUSION: Serum gel or non-gel tubes might be used interchangeably for 11 analytes chilled or at 24 degrees C, whereas some restrictions must be applied for glucose, AST, BUN, HDL, and uric acid.

Effects of hemolysis interferences on routine biochemistry parameters.

INTRODUCTION: Hemolysis is still the most common reason for rejecting samples, while reobtaining a new sample is an important problem. The aim of this study was to investigate the effects of hemolysis in different hemolysis levels for mostly used biochemical parameters to prevent unnecessary rejections. MATERIALS AND METHODS: Sixteen healthy volunteers were enrolled in the study. Four hemolysis levels were constituted according to hemoglobin concentrations and they were divided into five groups: Group I: 0-0.10 g/L, Group II:0.10-0.50 g/L, Group III: 0.51-1.00 g/L, Group IV: 1.01-2.50 g/L, Group V: 2.51-4.50 g/L. Lysis was achieved by mechanical trauma. RESULTS: Hemolysis interference affected lactate dehydrogenase (LD) and aspartate aminotransferase (AST) almost at undetectable hemolysis by visual inspection (plasma hemoglobin < 0.5 g/L). Clinically meaningful variations of potassium and total bilirubin were observed in moderately hemolyzed samples (hemoglobin > 1 g/L). Alanine aminotransferase (ALT), cholesterol, gamma glutamyltransferase (GGT), and inorganic phosphate (P) concentrations were not interfered up to severely hemolyzed levels (hemoglobin: 2.5-4.5 g/L). Albumin, alkaline phosphatase (ALP), amylase, chloride, HDL-cholesterol, creatine kinase (CK), glucose, magnesium, total protein, triglycerides, unsaturated iron binding capacity (UIBC) and uric acid differences were statistically significant, but remained within the CLIA limits. CONCLUSION: To avoid preanalytical visual inspection for hemolysis detection, improper sample rejection, and/or rerun because of hemolysis, it is recommended in this study that, routine determination of plasma or serum free hemoglobin concentrations is important. For the analytes interfered with hemolysis, new samples have to be requested.

Relationship between severity of coronary artery disease and apolipoprotein E gene polymorphism.

OBJECTIVE: To explore the possible contribution of the apolipoprotein (apo) E polymorphisms to the extent and severity of coronary artery disease (CAD) related to lipid metabolism. METHODS: Overall, 53 Turkish patients, aged 54+/-11 years defined by coronary angiography were included in this cross-sectional study. Reardon's coronary artery scoring was used. Serum lipids were measured with enzymatic colorimetric methods. Apolipoproteins were measured with nephelometry. Apolipoprotein E gene polymorphisms were determined by the reverse hybridization method. Statistical analyses were performed using one-way ANOVA, Kruskal-Wallis and Chi- square tests. RESULTS: The genotype frequencies were 7.5% for E2/E3, 77.4% for E3/E3 and 15.1% for E3/E4. The E2 allele frequency was slightly lower than E4 allele. There were no significant differences between apo E2/E3, E3/E3 and E3/E4 genotypes for severity scorings (26, 41 and 32 respectively, p=0.30) and extent scorings (3.2, 5.5, 4.5, p=0.17). It was found that the most of patients who had E2/3 and E3/4 alleles had low severity scores. On the other hand, there were no significant score difference for patients who had E3/3 alleles. Lipids were not significantly different among the different genotypes. The E3 allele was associated with high apo B levels compared with E2 and E4 genotypes. It was found that severity and extent of disease were not related with lipid metabolism. CONCLUSION: We concluded that there were no statistically significant differences between genotypes for extent and severity scorings, but the apo E3 allele is associated with more severe disease than E2 allele. These associations with severity were mediated not only by changes in lipid metabolism but may be also by other mechanisms in CAD patients.

Serum leptin levels in rheumatoid arthritis and relationship with disease activity.

OBJECTIVES: This study was performed to evaluate serum leptin levels in rheumatoid arthritis (RA) patients and investigate the correlation with serum tumor necrosis factor alpha (TNF-alpha) levels and clinical and laboratory parameters of disease activity. METHODS: Fifty patients with RA and 34 control subjects were included. Disease activity score 28 (DAS28) was calculated for each patient. Laboratory activity was assessed by examining erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Immunoradiometric assay was used for measuring serum leptin levels (ng/mL). Serum TNF-alpha levels (pg/mL) were measured by sandwich enzyme-linked immunosorbent assay method in 41 of 50 RA patients and in 24 control subjects. RESULTS: Age, sex and body mass index (BMI) did not show a statistically significant difference between RA and control subjects (P > 0.05). Serum leptin levels were higher in RA (P = 0.000). In RA patients, there were no correlations between serum leptin levels and disease duration, swollen and tender joint counts, DAS28, CRP, ESR, serum TNF-alpha levels, oral glucocorticoid and methotrexate usage (P > 0.05). There was no statistically significant serum leptin level difference between patients with high disease activity and mild and low disease activity (P = 0.892). Serum leptin levels positively correlated with BMI in both patient and control groups (P < 0.05). In both groups, mean serum leptin levels were higher in women than men. CONCLUSIONS: Even though serum leptin levels were found to be significantly higher in RA patients than in control subjects in this study, there was no correlation between serum leptin levels and TNF-alpha levels, clinical and laboratory parameters of disease activity. However serum leptin levels positively correlated with BMI in both patient and control groups. In RA, circulating leptin levels do not seem to reflect disease activity.

Serum osteocalcin levels in hyperthyroidism before and after antithyroid therapy.

Hyperthyroidism is characterized by accelerated bone turnover, caused from direct stimulation of bone cells by increased thyroid hormones. In this study, we aimed to investigate serum osteocalcin levels as a bone formation marker, before antithyroid (propylthiouracil) therapy at hyperthyroid stage and after antithyroid therapy at euthyroid stage of the patients. Twenty four hyperthyroid patients (18 females, 6 males) and 20 (13 females, 7 males) healthy controls were included into this study. Blood and urine samples were taken before medical treatment at hyperthyroid state, and after the antithyroid therapy until the patients reached the euthyroid state. Serum alkaline phosphatase, osteocalcin, calcium, phosphorus, Free T3, Free T4, TSH and urine calcium/creatinine levels were assessed. We found a significant decrease in serum osteocalcin (p=0.006), urinary calcium/creatinine (p=0.004), and serum phosphorus (p=0.038) levels in euthyroid state in comparison to hyperthyroid state. The increases in serum bone formation marker osteocalcin and bone resorption marker urinary calcium/creatinine levels in hyperthyroid state compared to euthyroid state in our study confirmed that hyperthyroid patients have high bone turnover. We conclude that, hyperthyroid patients has high bone turnover of formation and resorption even after attainment of euthyroidism. Osteocalcin and urine calcium/creatinine are sensitive markers in documenting bone remodeling during treatment of hyperthyroidism.