Laboratory Findings in Various Platelet and Coagulation Disorders

A peripheral-blood smear is a vital investigation tool in most cases to confirm a low platelet count and the presence or absence of other diagnostic features, such as red-cell fragmentation, platelet morphologic abnormalities, or evidence of dysplasia or hematinic deficiency.

Laboratory Findings in Various Platelet and Coagulation Disorders

Condition Prothrombin Time Activated Partial-Thromboplastin Time Fibrinogen Level d-Dimer Level Bleeding Time Platelet Count Findings on Blood Smear
Vitamin K deficiency or use of vitamin K antagonist Prolonged Normal or mildly prolonged Normal Unaffected Unaffected Unaffected
Aspirin or thienopyridines Unaffected Unaffected Unaffected Unaffected Unaffected Unaffected
Liver failure
Early stage
End stage
Prolonged
Prolonged
Unaffected
Prolonged
Unaffected
Low
Unaffected
Increased
Unaffected
Prolonged
Unaffected
Decreased
Uremia Unaffected Unaffected Unaffected Unaffected Prolonged Unaffected
Disseminated intravascular coagulation Prolonged Prolonged Low Increased Prolonged Decreased Fragmented red cells
Thrombotic thrombocytopenic purpura Unaffected Unaffected Unaffected Unaffected Prolonged Very low Fragmented red cells
Hyperfibrinolysis Prolonged Prolonged Low Very high Possibly prolonged Unaffected

 
 
References:

  1. Hunt BJ. Bleeding and coagulopathies in critical care. N Engl J Med. 2014 Feb 27;370(9):847-59. [Medline]
  2. Parker RI. Etiology and treatment of acquired coagulopathies in the critically ill adult and child. Crit Care Clin. 1997 Jul;13(3):591-609. [Medline]

Created Jul 21, 2014.

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