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)
Note
- 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
Military Obstetrics & Gynecology
© 2003, 2004, 2005, 2006 Medical Education Division,
Brookside Associates, Ltd.
All rights reserved
|