Document Type



Pathology and Laboratory Medicine


Objective: The aim of this Q-probes study was to evaluate the precision of replicate specimens.Methods: This Q-probes study done at the Clinical Laboratory, The Aga Khan University Hospital Karachi is about routine chemistry analytes because of their importance in critical care patients. The analytes data was collected for six months from April to September 2002. There were total 358 samples, which were given for reanalysis during this period under the constant working conditions. After analysis, results of both the runs on different days, were compared to determine the percent difference between the results. After calculating the percent difference, the results were either accepted or rejected on the basis of guidelines set by CLIA 88(Clinical Laboratories Improvement Amendment 1988).Results: Among 358 results, 5 were rejected according to the criteria selected. All of these results were then subjected to statistical analysis for calculating statistical significance. As our Null hypothesis was that the prevalence of rejected results were more than 2% with an acceptable limit of less than or equal to 2%. We failed to accept the Null hypothesis that means that it did not exceed the acceptable limits (p-value = 0.962930) with the Confidence Interval range of 0.2 -2.6 where Upper Confidence Interval is still less than 5% for a p-value of 0.05. The rejection of null hypothesis favors high precision between the two sets of results in our studied population.CONCLUSION: It is concluded that Q-Probes study of replicate specimens at the Clinical Laboratory at The Aga Khan University Hospital is within the acceptable limits. These figures show that a high quality precision is maintained among the observed specimens. This is an ongoing exercise and studies like these should be a continuous process to maintain and enhance the quality of Laboratory results).


Journal of Pakistan Medical Association