Determination of analytical performances of NT-proBNP and aPTT tests with three methods

INTRODUCTION: This study aimed to evaluate the analytical performances of N-terminal pro-B-type natriuretic peptide (NT-proBNP), which has not been investigated before, and activated partial thromboplastin time (aPTT), which has been the subject of little research, using the six sigma methodology and to calculate the quality goal index values of low-performing parameters. It was aimed to evaluate the analytical process with three methods by presenting this performance with Operation specifcation charts, which have been done in few other studies.
METHODS: Three consecutive months of internal quality control data obtained from NT-proBNP and aPTT tests, twice daily, and data obtained from a monthly external quality control program were used. Sigma values were calculated using the calculation of Sigma=(Total allowable error-bias)/(Coefficient of variation) and shown with Operation specifi-cation charts (OPSpecs). Quality goal index (QGI) was calculated for those with sigma <6.
RESULTS: The sigma values for levels 1 and 2 of the NT-proBNP test were calculated as 5.06 and 5.65, and the perfor-mance status was determined as very good. The sigma values for levels 1 and 2 of the aPTT test were calculated as 4.28 and 3.56, respectively, and this was evaluated as moderate and good performance. The Quality goal index values (QGI) for levels 1 and 2 of the NT-proBNP test were calculated as 0.11 and 0.12, respectively. The Quality goal index (QGI) values for levels 1 and 2 of the aPTT test were calculated as 0.90 and 0.75, respectively.
DISCUSSION AND CONCLUSION: Both tests had moderate, good and very good performance. It is of great importance to increase quality standards in laboratory tests. In this direction, continuous improvement-oriented initiatives should be implemented to make analytical processes more competent.