What is a CO2 blood test?

二氧化碳测试测量血清中二氧化碳（CO2）的量，这是血液的液体部分。二氧化碳测试也可以称为：

  • a carbon dioxide test
  • a TCO2 test
  • 总CO2测试
  • 碳酸氢盐测试
  • an HCO3 test
  • a CO2 test-serum

You may receive a CO2 test as a part of a metabolic panel. A metabolic panel is a group of tests that measure electrolytes and blood gases.

人体包含两种主要形式的二氧化碳：

  • HCO3 (bicarbonate, the main form of CO2 in the body)
  • PCO2 (carbon dioxide)

你的医生可以使用这个测试来确定其他e’s an imbalance between the oxygen and carbon dioxide in your blood or a pH imbalance in your blood. These imbalances can be signs of a kidney, respiratory, or metabolic disorder.

Your doctor will order a CO2 blood test based on your symptoms. Signs of an imbalance of oxygen and carbon dioxide or a pH imbalance include:

  • 呼吸急促
  • 其他呼吸困难
  • 恶心
  • vomiting

这些症状可能指向肺部功能障碍，涉及氧气和二氧化碳之间的交换。

如果您接受氧气治疗或进行某些手术，则需要经常测量血液的氧气和二氧化碳水平。

二氧化碳血液测试的血液样本可取自静脉或动脉。

静脉注射血液样本

静脉穿刺是用来描述从静脉取的基本血液样本的术语。如果您的医生只想测量HCO3，您的医生将订购一个简单的静脉穿刺血液样本。

为了获得静脉注射血液样本，医疗保健提供者：

  • 用杀菌性杀菌剂清洁位点（通常是肘部的内部）
  • 将弹性带缠绕在您的上臂，使静脉充满血液肿胀
  • 轻轻插入一根针中的静脉，并在附着的管中收集血液，直到满
  • 去除弹性带和针头
  • covers the puncture wound with sterile gauze to stop any bleeding

动脉血液样本

Blood gas analysis is often a part of the CO2 test. A blood gas analysis requires arterial blood because the gases and pH levels in the arteries different from venous blood (blood from a vein).

动脉在整个体内携带氧气。静脉将代谢废物和脱氧血液带到肺部，以二氧化碳和肾脏的肾脏呼气。

This more complicated procedure is done by a practitioner trained to safely access arteries. Arterial blood is usually taken from an artery in the wrist called the radial artery. This is the major artery in line with the thumb, where you can feel your pulse.

或者，可以从肘部的肱动脉或腹股沟股动脉中收集血液。为了获得动脉血液样本，从业者：

  • 用杀菌性防腐剂清洁现场
  • gently inserts a needle into the artery and draws blood into an attached tube until it is full
  • 去除针头
  • applies pressure firmly to the wound for at least five minutes to ensure the bleeding stops. (Arteries carry blood at higher pressures than veins, so it takes more time for the blood to form a clot.)
  • puts a tight wrap around the puncture site that will need to stay in place for at least an hour

您的医生可能会请您fast在血液检查之前，或停止进食。您的医生可能还会要求您在测试前停止服用某些药物，例如皮质类固醇或抗酸剂。这些药物增加了体内碳酸氢盐的浓度。

There are slight risks associated with both venipuncture and arterial blood tests. These include:

  • excessive bleeding
  • fainting
  • 头晕
  • 血肿，是皮肤下的一团血肿
  • infection at the puncture site

After the blood draw, your practitioner will ensure that you’re feeling well and will tell you how to care for the puncture site to reduce the chance of infection.

The normal range for CO2 is 23 to 29 mEq/L (milliequivalent units per liter of blood).

The blood test often measures blood pH along with CO2 levels to further determine the cause of your symptoms. Blood pH is a measurement of acidity or alkalinity.碱性病is when your body fluids are too alkaline.酸中毒另一方面，当您的体液过于酸性时。

Typically, a blood is slightly basic with pH measurement of close to 7.4 in maintained by the body. Normal range from 7.35 to 7.45 is considered neutral. A blood pH measurement less than 7.35 is considered acidic. A substance is more alkaline when its blood pH measurement is greater than 7.45.

低碳酸氢盐（HCO3）

A test result of low bicarbonate and low pH (less than 7.35) is a condition called metabolic acidosis. Common causes are:

A test result of low bicarbonate and high pH (more than 7.45) is a condition called呼吸道碱中毒. Common causes are:

高碳酸氢盐（HCO3）

A test result of high bicarbonate and low pH (less than 7.35) is a condition calledrespiratory acidosis. Common causes are:

高碳酸氢盐和高pH值的测试结果（超过7.45）是一种称为代谢碱中毒的疾病。常见原因是：

  • chronic vomiting
  • 低钾水平
  • 不足驱动，涉及呼吸缓慢和消除二氧化碳的减少

如果您的医生发现二氧化碳不平衡表明酸中毒或碱性病，他们将研究这种失衡的原因并适当治疗。由于原因有所不同，因此治疗可能涉及生活方式改变，药物和手术的结合。