Here are the some recommendations of the use of platelet transfusion.

If you go to BCSH guidelines, you can get the full version.

Prophylaxis for surgery

Bone marrow aspiration and biopsy may be performed in
patients with severe thrombocytopenia without platelet
support, providing that adequate surface pressure is
applied (grade C, level IV).
• For lumbar puncture, epidural anaesthesia, gastroscopy
and biopsy, insertion of indwelling lines, transbronchial
biopsy, liver biopsy, laparotomy or similar procedures, the
platelet count should be raised to at least 50 · 109 ? l
(grade B, level III).
• For operations in critical sites such as the brain or eyes,
the platelet count should be raised to 100 · 109 ? l (grade
C, level IV).
• It should not be assumed that the platelet count will rise
just because platelet transfusions are given, and a
preoperative platelet count should be checked to ensure
that the above thresholds have been reached.

Massive transfusion
A platelet count of around 50 · 109 ? l is expected when red
cell concentrates equivalent to approximately two blood
3volumes have been transfused (Hiippala, 1998).
Recommendations (grade C, level IV).
• There is consensus that the platelet count should not be
allowed to fall below 50 · 109 ? l in patients with acute
bleeding (BCSH, 1988; Consensus Conference on Platelet
Transfusion, 1998; Stainsby et al, 2000).
• A higher target level of 100 · 109 ? l has been recommended
for those with multiple trauma or central
nervous system injury (Development Task Force of
the College of American Pathologists, 1994; Horsey,
1997).

CONTRAINDICATIONS TO PLATELET TRANSFUSIONS

Thrombotic thrombocytopenic purpura (TTP)

Guidelines on the diagnosis and management of the
thrombotic microangiopathic haemolytic anaemias have
been published (BCSH, 2003b). Platelet transfusions are
contraindicated unless there is life-threatening haemorrhage,
as they have been temporarily associated with
exacerbation of TTP (Harkness et al, 1981; Gordon et al,
1987).

Heparin-induced thrombocytopenia (HIT)

HIT is a drug-induced immune thrombocytopenia that is
frequently associated with severe thrombosis (Warkentin
et al, 1998). Platelet transfusions should not be administered
as acute arterial thrombosis can result (Babcock et al,
1976; Cimo et al, 1979).

Full guideline in PDF file