What does aPTT prolongation indicate?
APTT evaluates the coagulation factors of the intrinsic pathway - VIII, IX, XI, XII and the common pathway. Its prolongation occurs in hemophilia A and B, von Willebrand factor deficiency, severe liver diseases, disseminated intravascular coagulation syndrome, and also in the presence of a lupus anticoagulant. Almost the most common use is to monitor therapy with unfractionated heparin: the dose is selected so that the aPTT is 1.5–2.5 times higher than normal, which requires regular laboratory monitoring. A shortening of the indicator indicates a tendency to thrombus formation. APTT is included in the standard preoperative examination: its prolongation before intervention requires clarification of the cause, otherwise serious bleeding during surgery is possible.
How to prepare to donate blood
- on an empty stomach 8–12 hours, you can drink water
- Eliminate alcohol and intense exercise per day
- no smoking in an hour
- donate blood before physiotherapy, x-rays and massage
- Take medications in advance by agreeing with your doctor
How to read the result
Reference values depend on the method and equipment of the laboratory, so it is correct to compare results only within the same laboratory. A deviation of a few percent from the normal limit in itself rarely matters - the overall picture and dynamics are important.
The analysis must be interpreted by a doctor: an isolated indicator without a clinical context is often misleading and leads to unnecessary examinations.