Platelet Count

Platelets are formed primarily in the bone marrow. They are released into the blood stream where they normally live for about a week.

Platelets serve to assist in clotting, coagulation, and maintaining vascular integrity.

Elevated Platelet Levels may be found in:

  • Infections
  • Cancer (About half of those with elevated platelet levels will be found to have an underlying malignancy.)
  • Trauma
  • Asphyxia
  • Arthritis
  • Liver disease
  • Athletes
  • High altitudes

Low Platelet Levels (thrombocytopenia) may be found in:

  • Hemorrhage
  • Infections
  • DIC (Disseminated Intravascular Coagulation)
  • Severe Pre-eclampsia
  • HEELP syndrome (hemolysis, elevated liver enzymes, decreased platelet count)
  • Allergic reactions
  • Drug reactions
  • DDT exposure
  • Bone marrow suppression
  • ITP (idiopathic thrombocytopenic purpura)


  • Abnormal bleeding due to low platelet counts won't normally occur until platelets fall below 50,000. This number is approximate, however, as abnormal bleeding and platelet function depend on a number of factors, only one of which is the platelet count.
  • Patients taking as little as 350 mg of aspirin will inactivate enough of their platelets to experience abnormal bleeding. The platelet count in these patients will be normal, but many of the platelets will not be functional. After discontinuing the aspirin, the platelets in the body are promptly re-cycled and within 7 days, all aspirin effects will be gone.
  • Because of "clumping," platelet counts performed on an automated machine may provide falsely low platelet counts. A manual (visual, microscopic) count will be more reliable in these circumstances.

Normal Values*

Platelet Count 150,000-350,000/cu. mm

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.

Source: Operational Medicine 2001,  Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300

Gynecology and Obstetrics CD-ROM
Volumes 1-6
2004 Edition
Lippincott Williams & Wilkins
Copyright 2004
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