ABSTRACT
Background: Clinical Biochemistry tests comprise over one third of all hospital laboratory investigation. The laboratory accreditation requirement has become an important aspect in selecting the analysers for analysing and evaluating the samples. Recently accrediting bodies are focusing on the importance of total quality management and assessment of trueness of laboratory measurements. The present study aimed to evaluate the hepatic enzymes using a single analytical methodology in 2 different automated analysers (semi autoanalyser and fully automated analyser) to understand the reliability of instrumentation on analytical methodology that would fit the laboratory performance standard. Methods: A total number of 50 serum samples from adult patients requested for liver function tests at Shri Sathya Sai medical college and research institute were analysed. The samples were evaluated for hepatic enzymes on (Cobasmira) Autoanalyser and (Biosystems) Semi Autoanalyser using the same analytical methodology and the values were compared between the 2 automated analysers. Data analysis was done by appropriate statistical methods. Results: No large differences were obtained in the values between the 2 automated analysers. Mean ± SD of each of the hepatic enzyme analysed by automated analysers were very close to each other indicating a minimum bias. Pearson’s correlation and scattered diagram showed significant positive correlation at 95% confidence interval between 2 automated analysers. Conclusion: The findings of this study confirm that both the automated analysers were reliable for evaluation of hepatic enzymes.
ABSTRACT
The determination of ADA(adenosine deaminase) activity in pleural fluid is useful in differental diagnosis of pleural effusion. The conventional method of determining ADA activity used by Giusti was influenced by contamination of ammonia. Additionally, because Giusti's method was mannual method a determining the ADA activities in sample, was not easily automated. In 1993, Oosthuizen HM with collegues developed simple kinetic method for determining ADA activity. It was reliable and suiable method for automation. In this study, we have measured ADA activity in 162 patients with various pleural effusion by Hitachi 747 autoanalyser using the Oosthuizen kinetic method for the purpuse of determination of new diagnostic cut-off value for the tuberculous effusion and evaluation of the correlation between the conventional method and new automated method. This new method of an enzymatic reaction involves 2, 6-dichlorophenolindophenol dye(DICP), adenosine, xanthine oxidase(XO), and nucleoside phosphorylase(NP). The results were as follows: 1) The mean pleural ADA activity of the tuberculous effusion was 52.53 +/-16.43 U/L and significantly higher than that of other groups(p<0.001). If the diagnostic cut-off value of pleural ADA activity for tuberculous effusion is above 30 U/L, the sensitivity is 96% and the specificity is 90%. 2) The mean pleural to serum ADA activity ratio of the tuberculous effusion was 2.29+/-0.96 and it was also significantly higher than that of other pleural groups(p<0.001). If the diagnostic cut-off value of pleural to serum ADA activity ratio is 1.5, the sensitivity is 80% and the specificity is 88% in the diagnosis of tuberculous pleural effusion. 3) The new kinetic method is correlates well to Giuisti's conventional method(r=0.971). In conclusion, the new kinetic method described is easily automated and seems to be suitable for the routine determination of ADA activity.