Abstract
Introduction
Internal quality control (IQC) is a fundamental technique to detect errors in the analytical phase and ensure that the results produced from any assay are reliable for patient result in order to improve the quality of patient care. The study aims to determine the potential error of current internal quality control practice in biochemistry section at NPHL, identify preferable IQC rules based on Sigma Metrics, and identify the root cause of problems and provide recommendation.
Methods
Retrospective analysis was conducted by using the existing biochemistry IQC data of Humatrol N and Humatrol P in Lot 002 and Lot 003 of NPHL from 02 June, 2015 to 27 June, 2016. IQC of thirteen tests including Triglyceride (TRI), Glucose (GLU), Total Cholesterol (CHO), Creatinine (CREA), Uric acid (UA), Protein Total (PT), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Urea (URE), Calcium (CAL), Albumin (ALB), Amylase (AMY), and Gama Glutamyl Transferase (GGT) were measured in this study. The potential errors of these tests were detected when value of Total Error (TE) was smaller than value of Total Allowable Error (TEa) defined by the Clinical Laboratory Improvement Amendments (CLIA) Requirements. Sigma Metrics was calculated and plotted on Sigma Scale to identify the preferable IQC rules. The focus group discussion were conducted to identify the root cause of problems and provide recommendation.
Results
Potential errors for IQC of Humatrol N in Lot 002 were detected in CHO, CREA, URE, CAL, and ALB (TE: 11.9%, 20.3%, 15.5%, 0.28 mmol/l, and 14.1%, respectively). Potential errors for IQC of Humatrol P in Lot 002 were detected in CHO, CREA, URE, CAL, and ALB (TE: 10.8%, 17.4%, 14.2%, 0.47 mmol/l, and 13.2%, respectively). Potential errors for IQC of Humatrol N in Lot 003 were detected in GLU, CHO, CREA, AST, ALT, URE, CAL, and ALB (TE: 14.2%, 18.4%, 24.5%, 24.0%, 27.9%, 12.7%, 0.3 mmol/l, and 16%, respectively). Potential errors for IQC of Humatrol P in Lot 003 were detected in GLU, CHO, TP, URE, CAL, and ALB (TE: 17.4%, 12.2%, 25.2%, 10.4%, 0.49 mmol/l, and 16%, respectively). Multi rules was suggested to monitor IQC performance (Sigma scale ranged from 3 to 5). The four keys finding of problems relate to policy/regulation on reagent and supply, staff, Monitor/supervise were revealed and the recommendations have been provided to laboratory are include establish Stock Inventory Information System, IQC Information Management System, conduct advance staff training on IQC interpretation and troubleshooting, provide enough spare part and stabilizer, and regular maintenance on material and equipment.
Conclusion
When evaluated on the Total Error and the sigma metric, potential errors of IQC performance in NPHL were detected include five tests in IQC Humatrol N and P including CHO, CREA, URE, CAL, and ALB were outside desirable limits of TEa. The problems were identified by conducted focus group discussion, and the four priority actions were recommended to solve.