Last updated: Saturday, 05, February, 2011
Key InformationAppropriate Tests

The blood film should be examined in all cases of thrombocytopaenia and the platelet count repeated. A repeat count on a specimen collected in citrate may confirm EDTA associated clumping.

In vitro clumping of platelets is common in the presence of EDTA, leading to spurious thrombocytopaenia. Similarly, a partly clotted sample can lead to a falsely low result.

See Table 1 Artefactual results

FBC, blood film.

Bone marrow aspiration may be required if mechanism and/or cause is not obvious from clinical and/or blood film findings or if confirmation is required.

Reduced production

Isolated thrombocytopenia

  • Thiazide diuretics
  • Alcohol - has a direct marrow suppressant effect, as well as being associated with chronic liver disease and hypersplenism.

See Alcoholism

Congenital especially

  • Intra-uterine infection 

See Neonatal bleeding under Bleeding disorder

  • Wiskott-Aldrich syndrome 

See under Immunodeficiency

  • TAR syndrome

Amegakaryocytic thrombocytopenia with absent radii.

Increased destruction, margination, or loss

Immune - Autoimmune

See Immune thrombocytopenia


Lymphoproliferative disorder associated, especially

Drug induced, especially

Platelet antibody testing (for drug dependent antibodies) may be helpful.

  • Quinine/Quinidine

p>The commonest of the drug related causes of immune thrombocytopaenia.

  • Heparin 

See Heparin-induced thrombocytopenia

  • Gold salts


Viral infection associated, especially

EBV and CMV serology may be indicated.

HIV serology should be checked in all cases of suspected immune thrombocytopenia.


Immune - Alloimmune

Neonatal thrombocytopaenia

Platelet antibody testing and platelet antigen typing of parents.
See also Neonatal bleeding

Post transfusion purpura

Platelet antibody testing and platelet antigen typing on recipient and blood donors.



Sepsis/Infection, especially


This is a common cause of thrombocytopenia. Abnormal liver function tests may be helpful, however normal LFT's do not exclude the diagnosis. Imaging of the spleen by ultrasound or liver-spleen scan is recommended.