<unk>  may be suspected if blood tests show a falling platelet count in someone receiving<unk> , even if the<unk>  has already been discontinued. Professional guidelines recommend that people receiving<unk>  have a complete blood count (which includes a platelet count) on a regular basis while receiving<unk> . However, not all people with a falling platelet count while receiving<unk>  turn out to have<unk> . The timing, severity of the<unk> , the occurrence of new thrombosis, and the presence of alternative explanations, all determine the likelihood that<unk>  is present. A commonly used score to predict the likelihood of<unk>  is the "4 Ts" score introduced in 2003. A score of 0–8 points is generated; if the score is 0–3,<unk>  is unlikely. A score of 4–5 indicates intermediate probability, while a score of 6–8 makes it highly likely. Those with a high score may need to be treated with an alternative drug, while more sensitive and specific tests for<unk>  are performed, while those with a low score can safely continue receiving<unk> , as the likelihood that they have<unk>  is extremely low. In an analysis of the reliability of the 4T score, a low score had a negative predictive value of 0.998, while an intermediate score had a positive predictive value of 0.14 and a high score a positive predictive value of 0.64; intermediate and high scores, therefore, warrant further investigation. Element The 4T score for<unk><unk>  2 points if the fall in platelet count is >50% of the previous value, AND the lowest count (nadir) is 20–100 × 109/liter1 point if the fall is 30–50% or the nadir is 10–19 × 109/literNo points if the fall is less than 30% or the nadir is 9/liter. Timing 2 points if the fall is between days 5–10 after commencement of treatment1 point if the fall is after day 10. If someone has been exposed to<unk>  within the last 30 days and then has a drop in platelet count within a day of reexposure, 2 points are given. If the previous exposure was 30–100 days ago, 1 pointIf the fall is early but there has been no previous<unk>  exposure, no points. Thrombosis 2 points in new proven thrombosis, skin necrosis (see below), or systemic reaction1 point if progressive or recurrent thrombosis, silent thrombosis or red skin lesionsNo points if there are no symptoms. Alternative cause possible 2 points if no other cause1 point if there is a possible alternative causeNo points if there is a definite alternative cause. The first screening test in someone suspected of having<unk>  is aimed at detecting antibodies against<unk> -PF4 complexes. This may be with a laboratory test of the enzyme-linked immunosorbent assay type. This ELISA test, however, detects all circulating antibodies that bind<unk> -PF4 complexes, and may also falsely identify antibodies that do not cause<unk> . Therefore, those with a positive ELISA are tested further with a functional assay. This test uses platelets and serum from the patient; the platelets are washed and mixed with serum and<unk> . The sample is then tested for the release of serotonin, a marker of platelet activation. If this serotonin release assay (SRA) shows high serotonin release, the diagnosis of<unk>  is confirmed. The SRA test is difficult to perform and is usually only done in regional laboratories. If someone has been diagnosed with<unk> , some recommend routine Doppler sonography of the leg veins to identify deep vein thromboses, as this is very common in<unk> .
Heparin-induced thrombocytopenia
Sticky platelet syndrome
Venom-induced consumption coagulopathy
Pseudo gray platelet syndrome
Drug-induced thrombocytopenic purpura
Gray platelet syndrome
Disseminated intravascular coagulation
Immune thrombocytopenic purpura