Patient based real time quality control using average of normal approach

Patient based real time quality control using average of normal approachC onventional internal quality control (IQC) analysis strate- gies employed by laboratories involve periodic testing of QC sera.However, this strategy can detect only analytical errors at the scheduled QC run and there is no way to detect errors in the intervals between the run time.Further, preanalytical factors which affect patient's results are not reflected during IQC analysis.So, periodic IQC analysis delays error detection and is not useful for real time monitoring of results [1,2].Objectives: The limitation of internal quality control (IQC) based on daily running of commercially available QC material is that it is non-commutable and errors cannot be detected in between the scheduled runs.This study was carried out with the objective of finding the utility of patient based real time quality control (PBRTQC) in overcoming these limitations.Methods: This observational descriptive study was carried out in the clinical chemistry laboratory of a tertiary care hospital between July 2023 to December 2023.PBRTQC was initiated in the laboratory by using Average of Normal (AoN) approach for serum sodium and potassium.Patients' sample-based reference mean (RP M ) and standard deviation (RP SD ) were calculated from the previous six months' data using reference intervals as truncation limits.For the next 2000 samples, the mean was calculated for each block of 20 samples (x) and designated as x1, x2, x3...These block means were plotted on the LJ chart and alarms were raised on the violation of predefined control rules.These alarms were investigated and necessary corrective measures were implied in the laboratory.Results: RP M RP SD for sodium was 139.233.72 mEq/L and potassium was 4.260.45mEq/L.The scheduled IQC was within range during the study.Alarms were raised for x13, x28, x29, x30, x35, x36, x55, x74 and x96.The workup of these alarms revealed instrument calibration error in most of the cases.However, analysis of x35 and x36 revealed delayed transport, improper temperature maintenance and partial hemolysis.All responsible personnel were given training regarding sample transport procedure.Using real time monitoring, we were able to detect errors which would have otherwise gone unnoticed by conventional IQC.Conclusion: PBRTQC permits stringent quality control in analytical as well as pre-analytical phase of testing procedure, even during the intervals between scheduled IQC runs.Successful implementation of PBRTQC will provide additional confidence in reporting laboratory results.