Lopamudra Ray

Quantitative application of sigma metrics in medical biochemistry.

INTRODUCTION Laboratory errors are result of a poorly designed quality system in the laboratory. Six Sigma is an error reduction methodology that has been successfully applied at Motorola and General Electric. Sigma (σ) is the mathematical symbol for standard deviation (SD). Sigma methodology can be applied wherever an outcome of a process has to be measured. A poor outcome is counted as an error or defect. This is quantified as defects per million (DPM). A six sigma process is one in which 99.999666% of the products manufactured are statistically expected to be free of defects. Six sigma concentrates, on regulating a process to 6 SDs, represents 3.4 DPM (defects per million) opportunities. It can be inferred that as sigma increases, the consistency and steadiness of the test improves, thereby reducing the operating costs. We aimed to gauge performance of our laboratory parameters by sigma metrics. OBJECTIVES Evaluation of sigma metrics in interpretation of parameter performance in clinical biochemistry. MATERIAL AND METHODS The six month internal QC (October 2012 to march 2013) and EQAS (external quality assurance scheme) were extracted for the parameters-Glucose, Urea, Creatinine, Total Bilirubin, Total Protein, Albumin, Uric acid, Total Cholesterol, Triglycerides, Chloride, SGOT, SGPT and ALP. Coefficient of variance (CV) were calculated from internal QC for these parameters. Percentage bias for these parameters was calculated from the EQAS. Total allowable errors were followed as per Clinical Laboratory Improvement Amendments (CLIA) guidelines. Sigma metrics were calculated from CV, percentage bias and total allowable error for the above mentioned parameters. RESULTS For parameters - Total bilirubin, uric acid, SGOT, SGPT and ALP, the sigma values were found to be more than 6. For parameters - glucose, Creatinine, triglycerides, urea, the sigma values were found to be between 3 to 6. For parameters - total protein, albumin, cholesterol and chloride, the sigma values were found to be less than 3. CONCLUSION ALP was the best performer when it was gauzed on the sigma scale, with a sigma metrics value of 8.4 and chloride had the least sigma metrics value of 1.4.

A comparative study of serum aminotransferases in chronic kidney disease with and without end-stage renal disease: Need for new reference ranges

Background: Hepatic diseases are common among chronic kidney disease patients and liver function tests particularly serum liver enzymes play an important role in diagnosing and monitoring these patients. Serum aminotransferase levels commonly fall near the lower end of the range of the normal values in patients of chronic kidney disease (CKD). High-levels of serum alkaline phosphatase (ALP) can occur in these patients due to renal osteodystrophy. Thus, the recognition of liver damage in these patients is challenging. Aim: To compare the levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and ALP among three groups - CKD patients without end stage renal disease (ESRD), patients with ESRD and healthy controls. Materials and Methods: A retrospective, hospital-based study was carried out from 100 patients’ records from each group and serum AST, ALT and ALP values were noted. Results: Our study showed that serum AST and ALT levels were significantly lower in CKD patients both without and with ESRD compared to controls. Further, these two enzyme levels were also significantly lower in CKD patients with ESRD compared to CKD patients without the condition. Serum ALP levels were significantly higher in patients with and without ESRD as compared to the controls. However, the values did not differ significantly between patients with and without ESRD. Conclusion: Levels of serum aminotransferases were low in CKD with and without ESRD and the levels become lower as the severity of CKD increases. Thus, the study established the need for separate reference ranges of serum aminotransferase in different stages of CKD.

Prevalence of Metabolic Syndrome in Psoriasis Patients and its Relation to Disease Duration: A Hospital Based Case-Control Study.

INTRODUCTION Previous studies indicate a higher prevalence of metabolic syndrome in psoriatic patients. This study aimed to investigate the association of metabolic syndrome and its components with psoriasis. It also studied the relation between presence of metabolic syndrome and disease duration in psoriasis patients. MATERIALS AND METHODS This was a hospital-based, case-control study conducted with 30 clinically diagnosed patients of chronic plaque psoriasis and 30 age- and sex-matched control subjects. Height, weight, BMI, blood pressure and waist circumference were assessed in all the subjects. Fasting levels of serum glucose, serum triglycerides and serum HDL were estimated by automated clinical chemistry analyser. Metabolic syndrome was diagnosed by the presence of at least 3 criteria of NCEP ATP III with Asian modification for waist circumference. RESULTS Metabolic syndrome was more common in psoriatic patients than in controls but the difference was statistically insignificant (60% vs. 40%, p-value=0.12). The psoriasis group had a higher prevalence of elevated blood glucose levels and higher waist circumference compared to controls. Psoriasis patients had a higher prevalence of high triglyceride levels than controls, the difference being statistically insignificant (40% vs. 30%, p-value = 0.41). The prevalence of low HDL levels was significantly higher in cases compared to controls (86.7% vs. 60%, p-value = 0.02). There was no relation between presence of metabolic syndrome and duration of psoriasis. CONCLUSION Our findings suggest that metabolic syndrome as well as dyslipidaemia is commoner in psoriasis patients. This underlines the need for screening of all psoriasis patients for early diagnosis and treatment of associated metabolic syndrome to reduce the high burden of morbidity and mortality.

Factitious Biochemical Reports which are Caused Due to Paraproteinaemia in Multiple Myeloma - A Case Report.

Factitious biochemical reports result in the misguiding of clinicians, unnecessary retesting, wrong diagnoses and incorrect treatments. A vigilant biochemist identifies these factitious biochemical reports and alerts the clinician regarding the proper interpretation of the biochemical reports, thus preventing a misdiagnosis and an incorrect treatment. We are presenting a case report of a multiple myeloma patient who presented with factitious biochemical reports which were caused due to paraproteinaemia. In the present case, the patient presented with an underestimation of urea and creatinine, an underestimation of sodium, low albumin levels and high phosphate levels. On repeating the same tests after dilutions and deproteinizing, the effects of the paraproteins on the above mentioned tests were reduced. Thus, from the observations of our study, we suggest that the interference by paraproteinaemia can be reduced by analyzing the biochemical parameters after dilution and deproteinization.

High atherogenic index of plasma in subclinical hypothyroidism: Implications in assessment of cardiovascular disease risk

Background: A controversy exists regarding the association between subclinical hypothyroidism (SH) and dyslipidemia. Moreover, studies on lipid ratios and atherogenic index of plasma (AIP) in SH are rare, particularly in the Indian scenario. Aim: This study aimed to investigate abnormalities in conventional lipid profile, lipid ratios, and AIP in SH and attempted to correlate thyroid stimulating hormone (TSH) and AIP in SH. Materials and Methods: In this retrospective analysis of patient records of SH subjects and euthyroid subjects, age, free triiodothyronine, free thyroxine, TSH, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol, lipid ratios, and AIP were compared between the two groups. The correlation of TSH and AIP in SH was studied. Spearmans correlation, Mann–Whitney U-test and logistic regression analysis were performed. Results: Triglyceride, triglyceride/HDL-C, and AIP were significantly higher in SH as compared to euthyroid group, but there was no correlation between TSH and AIP in SH. AIP emerged as the significant single factor associated with SH in multiple logistic regressions. Conclusion: The positive association of dyslipidemia and SH indicates a need for regular screening of these patients to enable early diagnosis and treatment of dyslipidemia. Even in patients who have a normal conventional lipid profile, lipid ratios, and AIP have to be calculated for better assessment of atherogenic risk.

Agreement of Arterial Sodium and Arterial Potassium Levels with Venous Sodium and Venous Potassium in Patients Admitted to Intensive Care Unit

INTRODUCTION Electrolyte abnormalities are one of the common causes of morbidity and mortality in critically ill patients. The turnaround time for electrolyte reporting should be as low as possible. Electrolytes are measured conventionally in serum obtained from venous blood by electrolyte analyser which takes 20 to 30 min. Point of care analysers are now available where in electrolytes can be measured in arterial blood within 5 min. This study was done to study the agreement of arterial sodium and arterial potassium with venous sodium and venous potassium levels. MATERIALS AND METHODS Venous sodium and venous potassium levels and arterial sodium and arterial potassium levels were analysed on 206 patient samples admitted to Intensive Care Unit (ICU). The venous values were compared with the arterial values for correlation. Venous sodium was compared with arterial sodium by spearman correlation. Venous potassium was compared with arterial potassium by pearson correlation. RESULTS The mean value of arterial sodium was 134 and venous sodium was 137. The mean value of arterial potassium was 3.6 and venous potassium was 4.1. The correlation coefficient obtained for sodium was 0.787 and correlation coefficient obtained for potassium was 0.701. There was positive correlation of arterial sodium and arterial potassium with venous sodium and venous potassium indicating agreement between the parameters. CONCLUSION Arterial sodium and arterial potassium can be used instead of venous sodium and venous potassium levels in management of critically ill patients.

Correlation of Friedewald's calculated low-density lipoprotein cholesterol levels with direct low-density lipoprotein cholesterol levels in a tertiary care hospital

Background: One of the risk factors for the development of coronary heart disease is high low-density lipoprotein (LDL) cholesterol levels. National Cholesterol Education Program ATP III guidelines suggest drug therapy to be considered at LDL-cholesterol levels >130 mg/dl. This makes accurate reporting of LDL cholesterol crucial in the management of Coronary heart disease. Estimation of LDL cholesterol by direct LDL method is accurate, but it is expensive. Hence, We compared Friedewald′s calculated LDL values with direct LDL values. Aim: To evaluate the correlation of Friedewalds calculated LDL with direct LDL method. Materials and Methods: We compared LDL cholesterol measured by Friedewald′s formula with direct LDL method in 248 samples between the age group of 20-70 years. Paired t-test was used to test the difference in LDL concentration obtained by a direct method and Friedewald′s formula. The level of significance was taken as P < 0.05. Pearsons correlation formula was used to test the correlation between direct LDL values with Friedewald′s formula. Results: There was no significant difference between the direct LDL values when compared to calculated LDL by Friedewalds formula (P = 0.140). Pearson correlation showed there exists good correlation between direct LDL versus Friedewalds formula (correlation coefficient = 0.98). The correlation between direct LDL versus Friedewalds calculated LDL was best at triglycerides values between 101 and 200 mg/dl. Conclusion: This study indicates calculated LDL by Friedewalds equation can be used instead of direct LDL in patients who cannot afford direct LDL method.

Validation of Method Performance of pH, PCO2, PO2, Na+, K+ of Cobas b121 ABG Analyser

INTRODUCTION The introduction of a new method or new analyser is a common occurrence in clinical biochemistry laboratory. Blood gas measurements and electrolytes are often performed in Point-of-Care (POC) settings. When a new POC analyser is obtained, the performance of the analyser should be evaluated by comparison to the measurements with the reference analyser in the laboratory. OBJECTIVES Evaluation of method performance of pH, PCO2, PO2, Na(+), K(+) of cobas b121 ABG analyser. MATERIALS & METHODS The evaluation of method performance of pH, PO2, PCO2, Na(+), K(+) of cobas b121 ABG analyser was done by comparing the results of 50 patient samples run on cobas b121 with the results obtained from Rapid lab values (reference analyser). Correlation coefficient was calculated from the results obtained from both the analysers. Precision was calculated by running biorad ABG control samples. RESULTS The correlation coefficient values obtained for parameters were close to 1.0 indicating good correlation. The CV obtained for all the parameters were less than 5 indicating good precision. CONCLUSION The new ABG analyser, Cobas b121 correlated well with the reference ABG analyser (Rapid Lab) and could be used to run on patient samples.

Lipid accumulation product index as visceral obesity indicator in psoriasis: A Case–control Study

Background: Psoriasis has well-known associations with individual components of metabolic syndrome such as hypertension, dyslipidemia, insulin resistance, and obesity. Traditional anthropometric measurements of obesity such as waist circumference (WC) and body mass index (BMI) do not differentiate between subcutaneous fat and visceral fat, the latter being associated with cardiovascular risk factors. Lipid accumulation product (LAP) index is a measure of visceral fat and has been found to be a better predictor of cardiovascular risk. However, LAP index has not been well-studied in psoriasis patients. Aims and Objectives: Our objective was to find out if LAP index differs significantly between psoriasis patients and controls and whether LAP index shows a correlation with duration and severity of psoriasis. Materials and Methods: A case–control study was undertaken with 40 chronic plaque psoriasis patients and 42 controls. BMI and LAP index were calculated for all the patients and controls. Psoriasis area severity index (PASI) was calculated for all the psoriasis patients. Mann–Whitney U-test was done for comparing the age, BMI, WC, serum triglyceride, and LAP index between the cases and controls and to compare the LAP index between mild psoriasis and moderate-to-severe psoriasis groups. Spearmans correlation coefficient was used to assess the correlation of LAP index with duration of psoriasis and with PASI. Logistic regression models were done to assess the risk factors in psoriasis. Results: A statistically significant difference was observed between the LAP index of controls (23.79 ± 13.02) and that of psoriasis patients (46.42 ± 27.2). LAP index was significantly higher in the moderate-to-severe psoriasis group as compared to the mild psoriasis group. LAP index was a significant risk factor associated with psoriasis (OR = 1.07; 95% CI: 1.03 – 1.11). Conclusion: Calculation of LAP index in psoriasis patients helps in identification of more individuals at high risk of cardiovascular morbidity than traditional anthropometric measurements of obesity.

Psoriasis & cardiovascular morbidity: The missing links?

Psoriasis is a chronic papulosquamous disorder with considerable morbidity. The prevalence of psoriasis varies between 0.09 and 11.43 per cent of the population1. It used to be considered a disorder of cutaneous hyperproliferation. However, over the course of the last two to three decades, psoriasis has also been found to be associated with a number of systemic abnormalities. Simultaneously, new hypotheses have been proposed which focus on the continued systemic inflammation and T-cell-mediated mechanisms to explain the cutaneous and joint manifestations. It primarily involves Th1and Th17-mediated pathways, involving the release of proinflammatory cytokines such as interleukin-6 (IL-6), interferon-γ (IFN-γ) and tumour necrosis factor-alpha (TNF-α). TNF-α is one of the most important mediators in the pathogenesis of psoriasis, and many of the biologics used in the treatment of psoriasis are TNF-α antagonists2.