Quality Assurance in Medical Laboratories in Developing Countries: Assessment of Pre-Analytical Errors in a Chemical Pathology Laboratory in a Tertiary Hospital in Nigeria

BACKGROUND: The total testing process is made up of the pre-analytical, analytical and post analytical phases. Most of the non-conformities to laid down laboratory procedures are known to be at the pre-analytical phase, amounting to about 70% of errors in the total testing phase. Most laboratories, in instituting total quality assurance, concentrate mainly on the analytical phase and the post analytical phase. The ISO, in a bid to correcting this oversight introduced a modifiable quality indicator system which monitors laid down processes and procedures of the laboratories. AIM- This study was therefore designed to assess the pre-analytical phase of the testing process in a Chemical Pathology laboratory of a teaching hospital in southern Nigeria. METHODS- The ISO quality indicators were modified to suit the standard operations of the Preanalytical phase of the said laboratory. With the help of a questionnaire, non-conformities to these laid- down procedures were assessed. Defects per million (DPM) of each indicator were calculated and a sigma value assigned as the performance level. A sigma value below 3 was seen as unacceptable performance and that between 3 and 4 was seen as acceptable performance. Lastly a sigma value above 4 indicated good performance. RESULT- A total of 17 quality indicators were used to assess the pre-analytical phase and 12 (70.6%) had unacceptable performance levels while 2 (11.8%) had acceptable performance levels. Only 3(17.6%) of these indicators had good performance levels. CONCLUSION- A holistic look at the performance of the quality indicators of the pre-analytical phase in this study showed that about 71% of the pre-analytical quality indicators assessed had unacceptable performance levels; 12% had acceptable performance level and only 18% had good performance level. This grossly indicates very poor quality pre-analytical sample acquisition and processing procedures. Steps therefore need to be taken to rectify these errors.