Abstract

Background and Objective: One of the organizations that have proceeded for very high standard quality management programs, ISO 9001-2008, is medical diagnostic laboratories. One of the important goals of most laboratories in the implementation of this standard is to reduce the current costs of repeated tests.

Material and Methods: The number of repeated tests was evaluated in biochemistry section (Glucose, Urea, Creatinine, Cholesterol, Triglycerides, AST and ALT) and hormones (T3, T4, and TSH) in three stages (pre-standard implementation, three and nine months after performing program).  We analyze the data by Stat data software (version 8) using Pearson chi square test.

Results: The percentages of repeated tests for glucose, urea, creatinine, cholesterol, triglycerides, AST, ALT, T3, T4, TSH were 16.5, 2.57, 2.88, 12.7, 14.9, 10.38, 12.6, 3.55, 4.69, 1.85 for the first time  and 20.5, 5.56, 5.41, 7.25, 20.0, 27.2, 30.1, 0.3, 6.04, 3.08 for the second time and 8, 8.3, 9.2, 7.1, 12.8, 17.4, 19.5, 0.0, 5.81,1.01 for the third time, respectively. The changes in statistical analysis of urea, creatinine, cholesterol, AST, ALT, and TSH were significant. The percentage trend of repeated tests for urea and creatinine was increased while for TSH, it was decreased.

Conclusion: Due to the nature of the experiments and the principles governing repeated tests, the acceptance and implementation of the ISO 9001-2008 only to reduce costs by reducing the percentage of repeated tests cannot be  justified. To implement this process, all aspects of the effectiveness should be considered together.

Keywords: ISO 9001-2008, Medical Diagnostic Laboratory, Effectiveness, Cost Reduction.

Abstract

         Background and Objectives: Concentration low-density lipoprotein (LDL) is one of the strongest indicators of atherosclerosis and predicts the diagnosis of cardiovascular diseases. LDL measurement accuracy is very important. LDL can be measured directly, such as enzymatic and nephelometry methods or can be calculated using Friedewald's formula. Despite the development of enzymatic methods and LDL nephelometry still in most laboratories is calculated using Friedewald's formula. The aim of this study was an investigation of correlation coefficient between two methods of measuring LDL- cholesterol levels.

         Methods: This descriptive cross-sectional study, performed on the 1141 patients. Cholesterol, triglycerides, HDL, LDL all patients assayed by enzymatic method. For patients with triglyceride levels of less than 400 mg/dl had LDL levels were calculated by Friedewald's formula. Normal levels of LDL/HDL ratio of less than 3.5 were considered.

          Results: Of the 1141 patients participating in this study, 38.3 % men and 61.7 % women. The mean patient age was 46.3 ± 16.1 years. Mean serum cholesterol, triglycerides and HDL were 177.9 ± 41.1, 132.9 ± 73.2 and 45.8 ± 13.2 mg/dl, respectively. Average direct and calculated LDL concentration was 82.1 ± 23.1 and 105.5 ± 35.8, respectively. The direct measurement of LDL, LDL/HDL levels in 97.1% of cases was normal, while 85.1 % of the calculation of LDL were normal. Pearson correlation coefficients were obtained by two methods: 0.869 (p <0.001).

         Conclusion: Despite the favorable correlation between two methods of measurements of LDL, the results of a calculation method is more than direct method. This can have a negative impact on the judgment of the treating physician.

           Key words: LDL, Enzymatic Method, Friedewald's Formula.