Creatinine clearance test

定义

The creatinine clearance test helps provide information about how well the kidneys are working. The test compares the creatinine level in urine 与 creatinine level in blood.

选择的名字

Serum creatinine clearance; Kidney function - creatinine clearance; Renal function - creatinine clearance

How the Test is Performed

This test requires both a 尿样 和 血液样本. 你会 collect your urine for 24 hours 和 then have blood taken. Follow instructions exactly. This ensures accurate results.

How to Prepare for the Test

考试前, your health care provider may ask you to stop taking medicines that may affect the test results. These include some antibiotics 和 stomach acid medicines. Be sure to tell your provider about all the medicines you take.

DO NOT stop taking any medicine before talking to your provider.

考试的感觉如何

The urine test involves only normal urination. 没有不适.

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

Creatinine is a waste product of creatine. Creatine is a chemical the body makes to supply energy, mainly to muscles.

The creatinine clearance test compares the creatinine level in urine 与 creatinine level in blood. This gives an estimate of the glomerular filtration rate (GFR). GFR is a measure of how well the kidneys are working, mainly the kidneys' filtering units. These filtering units are called glomeruli.

Creatinine is removed, or cleared, from the body by the kidneys. If kidney function is abnormal, creatinine level increases in the blood because less creatinine is excreted through the urine.

正常的结果

Clearance is often measured as milliliters per minute (mL/min) or milliliters per second (mL/s). 正常值为:

• Male: 97 to 137 mL/min (1.65 to 2.33毫升/秒).
• Female: 88 to 128 mL/min (14.96 to 2.18毫升/秒).

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor to know about the meaning of your specific test results.

What Abnormal Results Mean

Abnormal results (lower than normal creatinine clearance) may indicate:

• Kidney problems, such as damage to the tubule cells
• 肾功能衰竭
• Too little blood flow to the kidneys
• Damage to the filtering units of the kidneys
• Loss of body fluids (dehydration)
• Bladder outlet obstruction
• 心脏衰竭

风险

There is little risk involved with having your blood taken. Veins 和 arteries vary in size from one person to another 和 from one side of the body to the other. Taking blood 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

L和ry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 106.

Oh MS, Briefel G, Pincus MR. Evaluation of renal function, water, electrolytes, 和 acid-base balance. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis 和 Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 15.