Assessment of Pre-Analytical Errors in Clinical Chemistry Specimens at a Diagnostic Laboratory in Borno State, North East Nigeria

Pre-analytical errors account for the majority of total laboratory errors and can significantly compromise the reliability of clinical chemistry results, with direct implications for patient diagnosis and management. This study assessed the types, frequency, and sources of pre-analytical errors in clinical chemistry specimens at State Specialist Hospital Maiduguri, Borno State, North East Nigeria. A prospective observational study documented all rejected and problematic specimens over a six-month period. Errors were classified into sample identification errors, inadequate sample volume, haemolysis, lipaemia, clotted samples, wrong tube type, and delayed processing. Rejection rates, staff awareness, and upstream collection practices were also evaluated. A total of 4,280 clinical chemistry specimens were received, of which 9.6% were rejected due to pre-analytical errors. Haemolysis was the most common error at 38.0% of rejections, followed by insufficient sample volume at 25.6% and sample labelling errors at 18.4%. Phlebotomy performed by unskilled staff and delays exceeding two hours from collection to processing accounted for the majority of haemolysis and clotting errors. The emergency ward generated disproportionately higher error rates. The study identifies preventable root causes of pre-analytical errors and recommends structured phlebotomy training, standardisation of sample collection protocols, real-time specimen rejection tracking, and feedback mechanisms between laboratories and clinical wards across Borno State health facilities. Keywords: pre-analytical errors, clinical chemistry, specimen rejection, haemolysis, Maiduguri