The risk of iatrogenic anaemia from frequent venesection could be reduced with the widespread adoption of small volume blood tubes.

A South Australian study of their use in haematology inpatients found small volume tubes could reduce the amount of blood collected by 42% compared to standard volume tubes.

The quality improvement project in the haematology unit at the Royal Adelaide Hospital found the change to small volume tubes saved about 8.5ml blood per patient per day (11.5 v 20ml).

The study also found no evidence that use of small volume tubes affected haematological and biochemical results or laboratory error reporting rates.

Co-author Dr Nick Myles, from the Haematology Directorate at SA Pathology told the limbic that iatrogenic blood loss was under-recognised outside paediatric and intensive care units despite clear evidence that it can contribute to anaemia.

“There is a lack of awareness that frequent venesection in these patients can result in harm so I think it is something that probably does require a bit more thought or recognition in the general medical community.”

“At the end of the day, the results of the paper are pretty unsurprising but it’s something that I think people just forget about.”

Small volume blood tubes are now used routinely in the haematology unit and a plan is in place to roll them out across the entire hospital.

Dr Myles said hospitals were ‘inherently resistant to change’.

“From a governance perspective, the hospital needed to make sure it wasn’t associated with any harm. There was always a risk that with using small tubes there might have been unfamiliarity with how to use them, a reduction in specimen integrity, or repeat blood tests that may have impacted patient outcomes.”

The observational study was unable to look at anaemia or transfusion rates and Dr Myles added no one has yet demonstrated small volume tubes reduce transfusion requirements.

“It would be something very difficult to prove particularly in haematology patients because there are a lot of other factors that influence anaemia in this group but certainly it would be very important to demonstrate in less acute, long standing medical and surgical patients.”