血细胞比容

定义

血细胞比容 is a blood test that measures how much of a person's blood is made up of red blood cells. This measurement depends on the number of and size of the red blood cells.

选择的名字

HCT

How the Test is Performed

A 血液样本 是必要的.

How to Prepare for the Test

No special preparation is necessary for this test.

考试的感觉如何

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 a slight bruise. 这很快就会消失.

Why the Test is Performed

The hematocrit is almost always done as part of a complete blood count (加拿大广播公司).

Your health care provider may recommend this test if you have signs of or are at risk for anemia. 这些包括:

• Before and after major surgery
• Blood in your stools, or vomit (if you throw up)
• Chronic medical problems, such as kidney disease or certain types of arthritis
• 在怀孕期间
• Fatigue, poor health, or unexplained weight loss
• 头痛
• 月经过多
• 白血病 or other problems in the bone marrow
• Monitoring during treatment for cancer
• Monitoring medicines that may cause anemia or low blood counts
• Monitoring of anemia and its cause
• 营养不良
• 问题集中

正常的结果

Normal results vary, but in general they are:

• 男:40.7% to 50.3%
• 女:36.1% to 44.3%

For babies, normal results are:

• 新生儿:45% - 61%
• 婴儿:32%到42%

The examples above are common measurements for results of these tests. Normal value ranges vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

Low hematocrit may be due to:

• 贫血
• 出血
• Bone marrow being unable to produce new red blood cells. This may be due to leukemia, 其他癌症, 药物毒性, 放射治疗, 感染, or bone marrow disorders 
• 慢性疾病
• 慢性肾病
• Destruction of red blood cells (hemolysis)
• 白血病
• 营养不良
• Too little iron, folate, vitamin B12, and vitamin B6 in the diet
• Too much water in the body

High hematocrit may be due to:

• Bone marrow disease that causes abnormal increase in red blood cells (polycythemia vera)
• Congenital heart disease
• Exposure to high altitude
• Failure of the right side of the heart
• Low levels of oxygen in the blood
• Scarring or thickening of the lungs
• Too little water in the body (脱水)

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 血液样本 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 buildup under the skin)
• Infection (a slight risk any time the skin is broken)

参考文献

Chernecky CC, Berger BJ. H. 血细胞比容血. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6日艾德. St Louis, MO: Elsevier Saunders; 2013:620-621.

克利格曼RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. 血液疾病. 在:克利格曼RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21艾德. Philadelphia, PA: Elsevier; 2020:chap 124.

意味着RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 149.

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 31.