钾测试

定义

This test measures the amount of potassium in the fluid portion (serum) of the blood. Potassium (K+) helps nerves and muscles communicate. It also helps move nutrients into cells and waste products out of cells.

Potassium levels in the body are mainly controlled by the hormone 醛固酮.

选择的名字

Hypokalemia test; Hyperkalemia test; K+

How the Test is Performed

需要血液样本. Most of the time, blood is 从静脉中抽出 located on the inside of the elbow or the back of the hand.

How to Prepare for the Test

Many medicines can interfere with blood test results.

• Your health care provider will tell you if you need to stop taking any medicines before you have this test.
• DO NOT stop or change your medicines without talking to your provider first.

考试的感觉如何

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

This test is a part of a basic or comprehensive metabolic panel.

You may have this test to diagnose or monitor kidney disease. The most common cause of a high blood potassium level is kidney disease.

Potassium is important to heart function.

• Your provider may order this test if you have signs of high blood pressure or heart problems.
• Small changes in potassium levels can have a big effect on the activity of nerves and muscles, 尤其是心脏.
• Low levels of potassium can lead to an irregular heartbeat or other electrical malfunction of the heart.
• High levels cause decreased heart muscle activity.
• Either situation can lead to life-threatening heart problems.

It may also be done if your provider suspects 代谢性酸中毒 (for example, caused by uncontrolled diabetes) or 碱中毒 (for example, caused by excess vomiting).

Sometimes, the potassium test may be done in people who are having an attack of 麻痹.

正常的结果

正常范围是3.7 to 5.2 milliequivalents per liter (mEq/L) 3.70 to 5.20 millimoles per liter (millimol/L).

Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

High levels of potassium (血钾过高)可能是由于:

• 艾迪生疾病 (罕见)
• 输血
• 某些药物, including angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), the potassium-sparing diuretics spironolactone, amiloride and triamterene, and beta adrenergic blockers
• 组织挤压损伤
• Hyperkalemic periodic 麻痹
• Hypoaldosteronism (very rare)
• Kidney insufficiency or failure
• 代谢或 呼吸性酸中毒
• Red blood cell destruction
• Too much potassium in your diet

钾含量低(低钾血)可能是由于:

• Acute or chronic diarrhea
• 库欣综合症 (罕见)
• Diuretics such as hydrochlorothiazide, furosemide, torsemide, and indapamide
• 高醛甾酮症
• Hypokalemic periodic 麻痹
• Not enough potassium in the diet
• 肾动脉狭窄
• 肾小管酸中毒 (罕见)
• 呕吐

风险

If it is hard to get the needle into the vein to take the blood sample, injury to the red blood cells may cause potassium to be released. This may cause a falsely high result.

参考文献

DB山. Disorders of potassium balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11日艾德. Philadelphia, PA: Elsevier; 2020:chap 17.

Patney V, Whaley-Connell A. Hypokalemia and 血钾过高. In: Lerma EV, Sparks MA, Topf JM, eds. 肾脏的秘密. 第四版. Philadelphia, PA: Elsevier; 2019:chap 74.

Seifter杰. 钾障碍. In: Goldman L, Schafer AI, eds. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 109.