A modified thrombin clotting time test as a quality control marker for heparin contamination in obstetric intraoperative cell salvage.

OBJECTIVE: To assess if a modified thrombin clotting time test could be used as a simple quality control (QC) method to screen for unfractionated heparin in the product obtained from obstetric intraoperative cell salvage cases before re-infusion. BACKGROUND: A national QC scheme has recently been piloted to monitor the quality of autologous blood being returned to the patient. Laboratory tests include full blood count and microalbumin. Unfractionated heparin testing should be performed to ensure that there is no gross contamination of heparin in the final product; however, presently, there is no quick cheap test available suitable for heparin detection. MATERIALS AND METHODS: Samples were collected into plain non-anticoagulated tubes and centrifuged at 2500 × g for 5 min. Supernatant was mixed with commercially available coagulated normal plasma and a thrombin clotting time test performed. RESULTS: Calibration runs demonstrated that our system was sensitive up to 0 · 14 IU mL(-1) heparin, linear between 0 · 08 and 0 · 14 IU mL(-1). CONCLUSION: We have shown that the thrombin clotting time test can be modified and used as a cheap and reliable marker for heparin contamination. We have successfully incorporated this modified test into our hospital's obstetric QC scheme.

Severe haemolysis and renal failure in a patient with paroxysmal nocturnal haemoglobinuria.

Transfusion of about 60 ml of ABO incompatible plasma in 4 units of pooled platelets precipitated severe haemolysis, unmasking the emergence of paroxysmal nocturnal haemoglobinuria (PNH), in a patient with aplastic anaemia. In vitro tests showed that her red cells were lysed by both ABO compatible and incompatible plasma from normal donors. The behaviour of this case and the in vitro results suggest that it might be hazardous to relax the longstanding recommendation on transfusing patients with PNH by restricting the washing of blood components to those containing ABO incompatible plasma.

Systematic pre-deposit autologous blood provision for elective surgery: an important contribution to hospital blood supply.

From the 8th of September 1987 to the 31st of July 1988 all patients scheduled for major elective orthopaedic surgery were systematically offered the facility of pre-deposit autologous blood storage. Of 251 patients, 204 (81%) were eligible to pre-donate, and of these only 9 declined to do so. 72% of the participants required only autologous blood at operation, 23% required some additional homologous blood. During the study period, autologous blood accounted for 10% of all blood transfused in the district, making a significant contribution to the local blood supply.