Check-in and sorting of centrifuged serum and lithium-heparin tubes may be unsuitable using a bulk input module.

The aim of this study was to establish that laboratory testing may be impaired by pouring and sorting of centrifuged tubes into a bulk input module. The values of 17 analytes, including albumin, aspartate aminotransferase (AST), bilirubin, urea nitrogen, C-reactive protein (CRP), calcium, chloride, cholesterol, creatine kinase (CK), creatinine, ferritin, glucose, lactate dehydrogenase (LDH), potassium, sodium, total protein, and thyroid-stimulating hormone (TSH), were measured in 29 centrifuged serum samples collected in tubes with gel separator and paired centrifuged lithium-heparin samples collected in tubes with gel separator, with (S-BIM) or without (S-NO-BIM) being poured and sorted by a bulk input module (Inpeco, Lugano, Switzerland). In serum tubes, significant differences were observed in S-BIM values of albumin, AST, cholesterol, ferritin, glucose, LDH, potassium, and sodium compared with S-NO-BIM, with bias of LDH exceeding the total allowable error. In lithium-heparin tubes, statistically significant differences were observed in S-BIM values of all parameters, except urea nitrogen, CRP, and sodium, compared with S-NO-BIM. The percentage bias of AST, LDH, glucose, and creatinine exceeded the total allowable error. These results demonstrate that check-in and sorting of centrifuged serum and lithium-heparin tubes may be unsuitable using a bulk input module.