This test is available between 0800 to 1200hrs Monday to Friday excluding public holidays. Please note that this test is not performed on weekends. Please contact the Haematology laboratory (ext 1672) before collecting to confirm it can be completed. Haematology Scientist to call RBH to confirm the test can be completed.
Specimens must be in the Main lab within 1 hour of collection. RBH must have sample 2 hours from collection. Morning collections must arrive into the laboratory before 1200. If a request is received at a collection centre that cannot be forwarded to arrive at the laboratory by this time, ask the patient to return the following morning. 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.
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