To be Requested by ICU only. Please note, an elevated Plasma Free Haemoglobin indicates haemolysis of red blood cells. It cannot indicate whether haemolysis occurred in vivo or in vitro, nor can it indicated the cause of haemolysis. Clinical correlation is required.

Samples must be hand delivered to the lab to avoid shaking, which will falsely raise the plasma free-haemoglobin. Normal operating plasma free-haemoglobin level is < 0.10 g/dL. This is performed 24-hourly whilst on ECMO (routinely taken with the daily blood samples) according to clinical need/ECMO clinician direction.

Samples are taken by passively filling a 10mL syringe carefully from the intra-arterial line access port. Do not connect to a negative pressure “vacutainer” for sampling. The plasma free-haemoglobin collection tube is filled from the syringe after removing the lid, gently injecting blood from the syringe and then replacing the lid. No needles are required.

Decision cut point: 100 mg/dL