Blood sample errors are a common occurrence and can happen for a variety of reasons.
Here are the 5 most common causes and how you can help to avoid them.
1. Clotted sample
Clotting can occur if your blood is not mixed thoroughly after collection (the tube needs to be inverted 5 - 10 times) or if you have taken a long time to collect your sample and the blood has clotted before mixing takes place. When collecting a finger-prick sample we recommend giving the container a gentle swirl after each drop of blood has been collected, to ensure that it mixes with the sample contents.
2. Haemolysed sample
A haemolysed sample occurs when some of the red blood cells burst and the haemoglobin within the cells escapes and spoils the surrounding sample. With finger-prick samples, this can happen if your finger has been squeezed too hard or if you scraped your finger on the side of the tube rather than letting the droplets drop down the tube gently.
3. Insufficient sample
When your sample is received at the laboratory it is spun and separated into the blood cells and the liquid (plasma) that surrounds the cells. If the amount of blood taken is too small, then the lab will struggle to produce enough plasma from it. The usual cause for this is if the blood bottle is under-filled, so always try to fill the tube to the upper line as indicated on your instruction leaflet.
4. The Sample is too old
If a sample is delayed in the post, it may be too old to be used for testing when it arrives. We try to limit the time your sample spends in the post, by providing a tracked postage returns envelope and asking that you use a priority postbox.
5. If your sample is not labelled correctly
If your sample is not labelled or there is information missing the laboratory may not be able to use this. Working to strict UKAS guidelines the laboratories must produce accurate medical records, and a sample without a completed label cannot be used.