• Thrombocytopenia is defined as platelets of less than 150 x 103/mcL. Symptoms such as bruising and petechiae usually occur at counts at 50 x 103/mcL and between 5-10x 103/mcL there is a high risk of spontaneous bleeding.

Clinical Features

Unprovoked gingival bleeding.
Petechiae in a patient with thrombocytopenia.
Petechiae on the tongue in a patient with thrombocytopenia.
Petechiae on the lower leg in a patient with thrombocytopenia.

Differential Diagnosis

Differential Diagnosis of Thrombocytopenia


Decreased production

Increased platelet destruction or use

Drug Induced

Comparison by Etiology

↓ PLT Yes Yes Yes Yes Yes
↑PT/INR No No No +/- Yes
MAHA No Yes Yes No Yes
↓ Fibrinogen No No No No Yes
Ok to give PLT Yes No No No Yes


Platelet Related

Factor Related


Algorithm for the Evaluation of Thrombocytopenia
  • Platelet count (CBC)
  • Additional workup per clinical presentation


Patient treatments are stratified by the presence or absence of bleeding and in the non bleeding patient by the platelet number and the presumed cause of the thrombocytopenia

Platelet Transfusion Thresholds

most if not all of the following thresholds are based on weak recommendations with low quality evidence[1]

  • <50K if planned lumbar puncture or neurosurgical procedure[2]
  • <20K if planned for central venous catheter placement (preference toward compressible site), or febrile patient
  • <10K in asymptomatic patients (unless due to ITP, TTP, or HIT)

There are no firm recommendations for transfusion thresholds in acute traumatic bleeding but many providers will opt for a goal of 100K, especially if there is evidence of ICH

Transfusion contraindications


  • 1 unit of platelets per 5kg body weight raises count by 50k


See Also


  1. Kaufman, R. et al. Platelet Transfusion: A Clinical Practice Guideline From the AABB. Annals of Internal Medicine. 2015. Vol 162. No. 3 205-214 Full Text
  2. Shuoyan, N. et al. Safety of Lumbar Punctures in Adult Oncology Patients with Thrombocytopenia. Blood 2015 126:1141