ABSTRACT
Aim: External Quality Assurance (EQA) is basic requirement of a medical laboratory to assess the quality assurance and achieve the accreditation. The available EQA schemes evaluate the analytical performances of the laboratory but neither evaluate pre analytical factors nor mimic actual laboratory process. PRE-EQC has combined both performances in single scheme and assisting the participant laboratories to take appropriate corrective action and interpretations.Design:Pre-Analytical monitoring evaluates transport condition, correlation of the stability of samples and temperature, storage condition and environment of the laboratory of the participants and its effect on the results. A sample is specially preparedto estimate haemolysis, lipemic and icteric index.Clinical Biochemistry:Serum, fluoride and biological fluid (CSF exempted) samples are pooled from the routine collection of specimens. Pooled fractions are homogenized in a rotary shaker for 10 minutes. The clear samples are poured in individual double pack primary containers, which are placed between two gel packs in a “biohazard” labelled plastic bag. Temperature is recorded, kept in insulated thermocol box and sent to the destination.Urine Routine & Microalbumin, Creatinine Examination:Urine sample is stabilized using preservative.
ABSTRACT
Aims: The sample retention policy for Clinical Chemistry analytes in accredited medical laboratories as per ISO 15189:2012 is 24 hrs. Serum/ plasma to be separated in aliquot within 20 minutes of collection unless the primary containers are gel vacutainers. Rigorous maintenance of such procedure is difficult and as a result the possibility of deviation from such schedule may not be very uncommon. The 1 year Turn Around Time (TAT) analysis of the laboratory is a good guide to find out time lag from sample collection to sample processing & average time of collecting samples in aliquot for retained sample testing. The laboratory retested 22 common analytes on the basis of such time lag and evaluated the deviation from 1st observation. The accumulated data has helped to evaluate and implement sample retention policy. Study Design: The average time lag from collection to completion of test performance of a batch is 4hrs± 30 minutes. The analytes were retested in the time lag. After accumulation of sufficient data the time lag increased to 6 hours±30 minutes which is the average lag from sample collection to end of the day duty personnel. In the 3rd phase total retention time ie, 24 hrs has been considered as time interval of retained sample retesting. But the samples remained at room temperature for 6hrs±30minutes before being preserved at 2°C-8°C. Hence time lag was (6hrs±30min) at room temperature and 17hrs ±30min at 2°C-8°C. The samples always retested from primary container. Place and Duration of Study: The study took place in JMD Diagnostics Private Limited, Kolkata, India. The duration of study is 2 yrs. Methodology: The analytes were tested in Cobas Integra 400plus system. The tests have been performed as routine tests and considered as 1st observation. 2nd observation values obtained after the specified time lag. The results obtained were compared using statistical software. Comparison of 1st and 2nd results and bias of all analytes were studied. Electrolytes have been eliminated from the study as the electrolytes are preferred to be retested from freshly collected sample. Labile parameters like L-Lactate, ammonia, bicarbonate were also not considered for the same reason. Conclusion: Only 3 analytes, total protein, total calcium and inorganic phosphorus cannot be preserved in primary containers. The analytes also need not to be separated within 20 minutes of collection. Upto 4hrs±30 minutes all the parameters have shown excellent correlation coefficient. Hence, the laboratory earns a time lag between collection to preservation of samples for these analytes. For other 19 analytes sample may be kept in primary container.