血小板计数

定义

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

选择的名字

血小板计数

How the Test is Performed

A 需要血液样本.

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

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. 这很快就会消失.

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 too much bleeding or clotting.

正常的结果

The normal number of platelets in the blood is 150,000 to 400,000 platelets per microliter (mcL) or 150 to 400 × 10⁹/L.

Normal value ranges may vary slightly. Some labs use different measurements or may test different specimens. Talk to your health care provider about your test results.

What Abnormal Results Mean

血小板计数低

A low platelet count is below 150,000 (150 × 10⁹/L). If your platelet count is below 50,000 (50 × 10⁹/L), your risk for bleeding is higher. Even every day activities can cause bleeding.

A lower-than-normal platelet count is called 血小板减少症. Low platelet count can be divided into 3 main causes:

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

Three of the more common causes of this problem are:

• 癌症 treatments, such as 化疗 or 辐射
• 药物和药品
• 自身免疫性疾病, in which the immune system mistakenly attacks and destroys healthy body tissue, such as platelets

If your platelet count is low, talk to your provider about how to prevent bleeding and what to do if you are bleeding.

血小板计数高

A high platelet count is 400,000 (400 × 10⁹/L)或以上.

A higher-than-normal number of platelets is called thrombocytosis. It means your body is making too many platelets. 原因可能包括:

• 缺铁
• After certain infections, major surgery or trauma
• 癌症
• 某些药物
• Bone marrow disease called myeloproliferative neoplasm (which includes 真性红细胞增多)
• Spleen removal (splenectomy)

Some people with high platelet counts may be at risk for forming 血凝块 or even bleeding too much. Blood clots can lead to serious medical problems.

风险

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

• 大出血
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

参考文献

Iancu-Rubin C, Cantor AB. 血小板生成. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8日艾德. Philadelphia, PA: Elsevier; 2023:chap 29.

谢弗艾. Approach to the patient with bleeding and thrombosis. In: Goldman L, 谢弗艾, eds. Goldman-Cecil Medicine. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 162.