This test is available between 0900 to 1400hrs Monday to Friday excluding public holidays. Specimens must be in the Main lab within 2 hours of collection. Morning collections must arrive into the laboratory before 1400. If a request is received at a collection centre, and the specimens cannot arrive at the laboratory by this time, ask the patient to return the following morning. Please note that this test is not performed on weekends. All investigations of platelet function are strongly dependent on the correct method of blood collection. If collecting several citrate tubes, it is very important to identify which tube was collected first (i.e. number all coag tubes in order of collection). When collecting, use a 21G or larger needle. Blood should be drawn directly into evacuated sodium citrate tubes. After collection ensure proper mixing with anticoagulant by gently inverting the tube by hand 3 or 4 times. If there is venous collapse or stoppage of blood flow during collection, discard the specimen as it will not be suitable for Platelet Function Testing. Handle specimen gently after collection - send to laboratory immediately. Do not send to laboratory via Lamson system.
Please contact the laboratory with any queries.
If this test is required please contact the on call Haematologist for suitability and advice. The patient must abstain from aspirin and related drugs for 14 days prior to the test. If the platelet count and PFA-200 test are within normal limits, it is unlikely that a clinically important platelet defect is responsible for excessive clinical bleeding. Drugs, alcohol,cigarette smoking, and fatty foods prior to testing may influence results of platelet aggregation studies. Mild forms of storage pool disease may have normal aggregation responses and may only be diagnosed by electron microscopy and measurement of specific granule release products after platelet stimulation. Clinically normal individuals may have reduced platelet responsiveness to adrenaline. VASCULAR DEFECTS should be excluded in patients with a bleeding tendency and a normal von Willebrand and platelet profile