Haemolysed samples
Causes of sample haemolysis and ways to avoid it
What is sample haemolysis?
Haemolysis of samples occurs when the red blood cells burst and release their contents into the serum. This can happen during blood sample collection and transport. It is not caused by processes within the laboratory. Haemolysis can prevent the accurate measurement of analytes.
Why are only some tests affected?
The Biochemistry analysers check all samples for haemolysis, and measure how much haemolysis is present. Some tests are affected by lower levels of haemolysis than others. For example, low levels of haemolysis affect the measurement of potassium, because potassium is released when the red cells burst. High levels of haemolysis affect all analytes, and no test results will be available. By not reporting tests that are affected, we ensure that patients do not receive misleading results.
How can sample haemolysis be avoided?
To avoid sample haemolysis, consider the following tips for blood collection and transport:
- Use an appropriate sized needle, not too small
- Use vacutainer tubes
- If using a syringe, pull the plunger gently
- Fill tubes to the correct volume
- Avoid transferring blood between tubes
- Mix samples gently
- Send samples to the lab as soon as possible
- Avoid extremes of temperature when storing/transporting samples