Hämolyse

Hämolyse means red blood cells have burst and released their contents into the surrounding serum or plasma. The laboratory notices it immediately, because the sample turns red rather than straw-coloured, and the degree is graded and reported.

It matters because it is not cosmetic. Substances present inside red cells at much higher concentrations than outside them are then measured too high, so potassium and LDH in particular become unusable, while other analyses are affected to varying degrees. The laboratory either refuses the affected values or reports them with a warning.

Almost all Hämolyse is caused during collection, which is the encouraging part, because that makes it preventable. These are the usual causes of it:

• The needle is too narrow for the vein being used.
• Suction on the syringe or the tube is too strong.
• The tourniquet stays on the arm for too long.
• The tube is shaken instead of being inverted gently.
• The tube is filled short, so the additive ratio is wrong.
• The sample stays somewhere warm before it is dispatched.

Capillary collection has its own version of the problem. Squeezing or milking the fingertip to coax out more blood is the single most common cause of Hämolyse in a kapillare Blutentnahme, and it is exactly what someone does when too little blood appears.

The consequence for a pharmacy is concrete, because a haemolysed sample means calling the customer back for a second venöse Blutentnahme, which costs the consumables, the appointment slot and a measure of confidence in the service.

Prevention is ordinary Präanalytik discipline, which means the right needle, gentle inversion, the correct fill volume and a Probenlogistik that moves the tube quickly.