Using Internal and External quality control data to improve analytical quality goals

BACKGROUND

Patient safety and errors are an important issue in laboratory medicine. Consequently, laboratory personnel are inventing better ways to address these challenges and improve patient care. Total Allowable Errors (TAE) have been used in quality management practices to evaluate performance of methods however, its performance is dependent on the selected Tea source. With a great number of (TEa) sources, the laboratorians face the difficulty in choosing the most appropriate TEa source as an analytical goal. In this study, we used bias and sigma metrics to select TEa sources that best fit the biochemistry performance at Soroti Regional Referral Hospital laboratory (SRRHL).

METHOD

Data for 10 biochemistry tests i.e. (Alb, ALT, AST, ALP, BT, BD, CHOL, CREA, GGT, and TP) was extracted from the Cobas C3111 Chemistry Analyzer at SRRHL from January to December 2018.
 

Four different TEa sources were chosen to estimate the Bias and sigma metrics i.e. Biological variation (BV), RiliBÄK (guidelines of the German medical association for the quality assurance of laboratory medical examinations), RCPA (Royal College of Pathologists of Australasia), and CLIA (Clinical Laboratory Improvement Amendments).
 

Bias was computed from the EQA results and sigma metrics from the IQC results for the four different TEa sources as
                                                                  Bias = [bias (%)/TEa (%)]*100.
                                                          Sigma metrics = [TEa (%) – bias (%)] / CV (%).
The obtained Bias and sigma metrics were plotted in a graphical tool and the percentage of biochemistry tests according to the TEa source in each area of the chart calculated.

RESULTS

For a total of 10 tests, four were located in area A of the chart: ALT, AST, CHOL, GGT. Two tests in area B, BT, BD. The performance of the two tests in area B were re-evaluated using biological variation as TEa source. Following the re-evaluation, the tests were located in area A of the chart. 

Four tests were located in area C of the chart (Alb, ALP, CREA and TP). These tests were re-evaluated using BV as TEa source. Following re-evaluation, all the tests were in area A except for TP.

CONCLUSION

In 6 out of 10 evaluated tests the analytical performance allowed for the selection of BV as TEa source. The TEa source that best suits the tests performance in the laboratory was the RiliBÄK.