18.4 LABORATORY ERRORS

Analysis of all cases reported to SHOT in 2014 shows that 2346/3017 (77.8%) were caused by error. Of these 334/1179 (28.3%) full cases originated in the laboratory, which is equivalent to what Linden et al. reported (90). In the 2014 SHOT report, laboratory errors include:

- Sample receipt and registration: Failure to take into account available historic information accounts for 60/94 (63.8%), demographic data entry errors for 25/94 (26.6%) and information missed by laboratory staff that was provided on the request form for 9/94 (9.6%)
- Testing: most errors that occurred in testing were due to procedural errors: Incomplete testing, Transcription errors, Misinterpretation of results. Among laboratory errors there were 9 ABO/D grouping errors all involved manual intervention (5 interpretation errors and 4 transcription errors). Despite recommendations for fully automated grouping some laboratories continue to perform manual ABO/D grouping for example in emergencies or out-of-hours, and in very small laboratories where large automation is not feasible
- Component selection: in 2014 SHOT report the following component selection errors are reported: selecting the wrong component (FFP when cryoprecipitate was requested), Late /omitted insufficient dose of anti-D Ig to women, Units that are not of correct specification (not irradiated or the correct phenotype), selection of expired units. These component selection errors could have been prevented if laboratory staff maintained their understanding, knowledge and skills within the transfusion laboratory 
- Component labelling, availability, handling and storage: Many cases in this category are due to labelling errors (n=50), where labels were transposed when more than 1 unit was issued to the same patient. In 44 cases expired units were not discarded but reissued to patients or cold chain errors occurred that resulted in units which had been out of controlled temperature being transfused to patients, 3 further labelling errors where the labels for 2 units that were intended for different patients were transposed
 
It appeared that a high number of laboratory errors took place outside of ‘‘core hours’’ and at night, when staff is fewer in number, may be relatively inexperienced and working under pressure. Unless the transfusion laboratory is appropriately staffed throughout the 24-h period, requests for transfusion at night should be restricted to urgent and emergency cases.