Navigate Up

Cancer Center - A-Z Index

#
Q
Y

Print This Page

Platelet count

A platelet count is a test to measure how many platelets you have in your blood. Platelets are parts of the blood that help the blood clot. They are smaller than red or white blood cells.

Alternative Names

Thrombocyte count

How the Test is Performed

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to Prepare for the Test

Most of the time you do not need to take special steps before this test.

How the Test will Feel

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

Why the Test is Performed

The number of platelets in your blood can be affected by many diseases. Platelets may be counted to monitor or diagnose diseases, or to look for the cause of excess bleeding or clotting.

Normal Values

The normal number of platelets in the blood is 150,000 - 400,000 platelets per microliter (mcL).

Normal value ranges may vary slightly. Some lab use different measurements or may test different specimens. Talk to your doctor about your test results.

What Abnormal Results Mean

LOW PLATELET COUNT

A low platelet count is below 150,000. If you do not have enough platelets, you may bleed too much.

If your platelet count is below 50,000, your risk of bleeding is much higher. Even every day activities can cause this bleeding. You need to know how to prevent bleeding and what to do if you have bleeding .

A lower-than-normal platelet count is called thrombocytopenia . Low platelet count can be divided into three major causes:

  • Not enough platelets are made in the bone marrow
  • Platelets are being destroyed while in the bloodstream
  • Platelets are being destroyed while in the spleen or liver

Three of the more common causes of this problem are:

  • Cancer treatments such as drugs or chemotherapy, as well as radiation
  • Drugs and medicines
  • Autoimmune disorders, in which occurs when the immune system mistakenly attacks and destroys healthy body tissue, such as platelets

HIGH PLATELET COUNT

A high platelet count is 400,000 or above

A higher-than-normal number of platelets (thrombocytosis) refers to when your body is making too many platelets

  • A type of anemia in which red blood cells in the blood are destroyed earlier than normal.
  • After certain infections, major surgery or trauma, allergic reactions
  • Cancer
  • Certain medicines
  • Chronic myelogenous leukemia (CML)
  • Polycythemia vera
  • Primary thrombocythemia
  • Recent spleen removal

Some people with high platelet counts may be at risk of forming blood clots. Blood clots can lead to serious medical problems

Risks

There is very little risk involved when having your blood taken.

References

Abrams CS. Thrombocytopenia. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 175.

Bain BJ. The peripheral blood smear. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 160.

Updated: 2/2/2013

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.


©  UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences
Supplemental content provided by A.D.A.M. Health Solutions. All rights reserved.

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

For UPMC Mercy Patients: As a Catholic hospital, UPMC Mercy abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices and/or procedures that contradict the moral teachings of the Roman Catholic Church.

© UPMC
Pittsburgh, PA, USA UPMC.com