Carbon Dioxide, Total
Carbon dioxide is a gas produced in the body as a bi-product of the process of metabolism. Contrary to what most people think, the human body requires carbon dioxide in its blood for health living. During the process of respiration, excess carbon dioxide is removed from the body and this is replaced by atmospheric oxygen; however there is still some level of carbon dioxide that remains in the blood. Having a low level of carbon dioxide in the blood or a high level of carbon dioxide in the blood will greatly affect some of the functioning in the body. These functions are associated to those of the cardiovascular system as well as the systems associated with cellular-based respiration. A low level of carbon dioxide in the blood will lead to reduced oxygen reaching the various cells and tissues of the body. An increase in carbon dioxide in the blood is also a problem for the body. It is therefore necessary to maintain the right carbon dioxide range in the body.
Carbon dioxide (chemical formula CO2) is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state, as a trace gas at a concentration of 0.039 per cent by volume.
As part of the carbon cycle known as photosynthesis, plants, algae, and cyanobacteria absorb carbon dioxide, light, and water to produce carbohydrate energy for themselves and oxygen as a waste product.But in darkness photosynthesis cannot occur, and during the resultant respiration small amounts of carbon dioxide are produced.Carbon dioxide is also produced by combustion of coal or hydrocarbons, the fermentation of liquids and the breathing of humans and animals. In addition it is emitted from volcanoes, hot springs, geysers and other places where the earth’s crust is thin; and is freed from carbonate rocks by dissolution. CO2 is also found in lakes at depth under the sea, and commingled with oil and gas deposits.The environmental effects of carbon dioxide are of significant interest. In the earth's atmosphere, it acts as a greenhouse gas which plays a major role in global warming and anthropogenic climate change. Also a major source of ocean acidification is CO2 which dissolves in water forming carbonic acid,which is a weak acid, because CO2 molecule ionization in water is incomplete.
High Carbon Dioxide Level in Blood
All living beings need air to breath. Air is a mixture of gases like carbon dioxide (CO2), oxygen (O2), carbon monoxide (CO), nitrogen (N2), hydrogen (H2), and noble gases. All mammals, including human, beings need oxygen to respire and exhale a mixture of carbon dioxide and a small amount of oxygen through their lungs. The major portion of carbon dioxide is present in the body either as bicarbonates (HCO3) or carbonic acid (H2CO3). Moreover, carbon dioxide is also present in a dissolved state in body.
The exchange of gases takes place at the alveoli level, which is an integral part of lungs. It's a passive phenomenon in which diffusion takes place. The balance between the levels of these two gases, viz. carbon dioxide and oxygen, is required for a healthy body. Any pathological condition may arise if the balance between the gases level gets disturbed inside the body.
If the carbon dioxide level arises in body, the state is known as hypercapnia. Similarly, if the level of oxygen reduces in the blood, it is known as hypoxia. All respiratory disorders include the imbalance in blood CO2 and O2 levels. A mild imbalance does not require intensive care but severe cases require medical attention on the spot.
A low level of carbon dioxide in the blood could be very harmful to the body. This condition is brought on by hyperventilation which is a situation where the individual breathes faster than he or she needs to. This may happen as a result of panic attacks or if the individual has consumed some drug that over stimulates the respiratory system. Carbon dioxide works to increase the acidity of the blood. When there is a low level of carbon dioxide in the blood, the blood will be alkaline in nature. This will lead to the blood vessels of the body constricting, thus reducing the flow of blood in the body. This is a situation that can be particularly dangerous as it can lead to reduced blood supply to the brain and other vital organs of the body. This problem leads to diminished consciousness, vision difficulties, muscle cramps and sudden anxiety on the part of the individual.
When the individual has a high level of carbon dioxide in the blood, the condition is known as hypercapnia. One of the most common causes of high levels of carbon dioxide in the body is hypoventilation. This means that the person is not breathing fast enough to support the functions of the body. This occurs when the individual is experiencing diminished consciousness or if he or she has some sort of lung disease or infection. High levels of carbon dioxide in the blood can cause flushed skin, increased blood pressure, muscle twitches, reduced brain and nerve function, headaches, confusion and lethargy. In extreme cases, the patient will need to be given oxygen to breathe so that the balance of oxygen in the blood as also the level of carbon dioxide is brought back to a normal level. When an individual experience an increase of carbon dioxide in the blood, it is important that this is brought back to normal. Long periods of enduring such a condition can lead to damage to internal organs such as the brain. It should be understood that breathing in a carbon dioxide rich environment will also disturb the normal carbon dioxide level in the blood.
The normal carbon dioxide level in the blood falls within the blood carbon dioxide range of 20 to 29 milliequivalent per liter of blood and this could be checked by conducting a blood carbon dioxide test. It should be understood that a change from the normal carbon dioxide level in the blood could be indicative of a number of different conditions. This is just one symptom that there is something awry with the functioning of the body. One could check w The first course of treatment when dealing with abnormal carbon dioxide levels involves the stabilization of level of carbon dioxide by using oxygen or breathing devices. It is only once the level is normalized that the patient will be put through a series of tests to determine what is causing the high or low level of carbon dioxide in the blood.
Symptoms For High Carbon Dioxide Level in Blood
The symptoms associated with high blood carbon dioxide levels include increased blood pressure, rapid pulse, rubor (redness), muscle twitches, headache, chest-pain, confusion, and fatigue. All of these symptoms depend on the severity of case. The various causes of high carbon dioxide level include vigorous exercise and numerous pathological conditions like chronic obstructive pulmonary disease (COPD), acidosis, lung infections, and atherosclerosis.
A high carbon dioxide level in body is related to some occupations too. A suitable example is working near a furnace or professional divers where the person has to hold his breath for long to go deep inside the ocean. Another reason for high CO2 is pollution and smoking, as in both the cases the alveoli gets damaged, leading to impairment in the exchange of gases.
The major organs which maintain the balance between carbon dioxide and oxygen are the liver and kidneys. So, a malfunctioning of any of these organs also leads to hypoxia or hypercapnia.
Treatment for High Carbon Dioxide Level in Blood
The initial treatment of unconscious patients with higher levels of carbon dioxide in their blood is artificial respiration and massage on the chest. In the majority of carbon dioxide poisoning cases, patients remain asymptomatic as there appear no specific symptoms of CO2 poisoning. A regular check up and follow up of these patients is advised.
In comparison to carbon monoxide poisoning, cases of carbon dioxide poisoning are less severe. Carbon monoxide (CO) gas is highly poisonous in nature. Even in decimal amounts, it is proved to be fatal, as it has a higher affinity than oxygen to get attached to hemoglobin molecules in blood, leading to hypoxia in the body cells. To maintain the proper balance of CO2 and O2 in blood, one should exercise daily and eat healthy. Though the body has its own defense mechanism, it is good to take precautions as it has rightly been said that prevention is better than cure.
The total CO2, (Carbon Dioxide, Total) test measures the total amount of carbon dioxide in the blood, mainly in the form of bicarbonate (HCO3-).
Bicarbonate is an electrolyte excreted and reabsorbed by the kidneys. It is used by the body to maintain the body’s acid-base balance (pH) and also maintain electrical neutrality at the cellular level together with sodium, potassium, and chloride.
This tests helps diagnose an electrolyte imbalance, acidosis or alkalosis as the result of a disease. It is prescribed in after symptoms such as weakness, confusion, prolonged vomiting, or respiratory distress that could indicate an electrolyte imbalance or acidosis or alkalosis.
The bicarbonate test is usually ordered along with sodium, potassium, and chloride as part of an electrolyte panel. It may be ordered as part of a routine exam or to help evaluate a chronic illness such as kidney disease and hypertension, and to monitor the effectiveness of treatment.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm.
A carbon dioxide test measures the total amount of the three forms of carbon dioxide (bicarbonate, carbonic acid, and dissolved carbon dioxide) in your blood. This test is also called a total carbon dioxide or TCO2 test.
Carbon dioxide (CO2) is a gaseous waste product made from metabolism. The blood carries carbon dioxide to your lungs, where it is exhaled. More than 90% of carbon dioxide in your blood exists in the form of bicarbonate (HCO3). The remainder of the carbon dioxide is either dissolved carbon dioxide gas (CO2) or carbonic acid (H2CO3).
Your kidneys and lungs balance the levels of carbon dioxide, bicarbonate, and carbonic acid in the blood. This test is usually done at the same time as an arterial blood gas test.
Carbon dioxide (CO2) plays an important role in the human body. It is a waste product of cellular metabolism, exhaled by the lungs at the same time that oxygen is inhaled. This waste product is involved in the transportation of oxygen from the blood, to the cells of the body. CO2 helps dilate the smooth muscle tissues and helps regulate the cardiovascular system. CO2 gets converted to carbonic acid, thereby becoming a primary regulator of the alkaline/acid balance of the body. Moreover, CO2 plays a role in the proper functioning of the digestive system. Thus, carbon dioxide in blood levels plays a very important role in the body. The normal concentration of CO2 in the bloodstream is 40 mm of Hg.
High Levels of Carbon Dioxide in the Blood (Hypercapnia)
When the level of CO2 goes beyond 45 mm of Hg in the arterial bloodstream, the condition is called hypercapnia (hypercarbia). The levels of CO2 in the body increase due to various factors such as hypoventilation, diminished consciousness, drug overdose, asthma, seizures or lung diseases. Hypoventilation is a condition that occurs when the ventilation is inadequate to perform the necessary gaseous exchange. The lack of adequate ventilation results in increased concentration of CO2 in the blood.
What Causes Hypercapnia?
•Inhaling excess CO2
Hypercapnia can also be caused when the body is exposed to environment comprising high concentrations of CO2, such as volcanic regions. Inhalation of exhaled CO2-rich air can also lead to high CO2 levels in the blood.
Sleep apnea is a condition in which the normal breathing pattern of a person is disturbed. The asleep person stops breathing, thereby stopping the intake of fresh oxygen supply. Moreover, carbon dioxide from the lungs is not exhaled. This automatically causes the oxygen levels in the blood to reduce and CO2 levels to increase, thereby resulting in hypercapnia.
•Chronic Obstructive Pulmonary Disorder (COPD)
This is a medical condition in which the person finds difficulty in breathing. When one inhales, air reaches the alveoli of the lungs and gaseous exchange takes place. However, in people with COPD, less air travels in and out of the body due to either damaged alveoli, inflamed alveoli or alveoli that have lost their elasticity. This results in less intake of oxygen and inability to expel carbon dioxide completely.
Sometimes, inadequate ventilation occurs in divers, resulting in an incomplete expulsion of CO2 from the blood, while exhaling. This happens because divers breathe into a full face diving mask, diving helmet or long snorkel, which fails to permit complete passage of CO2 into the environment. This results in inhalation of exhaled CO2 rich air. Since the diver is constantly exercising, the metabolic activity continues to increase, thereby producing more CO2. The final result is hypercapnia.
Symptoms of Hypercapnia
Some of the mild symptoms of this condition are lethargy, irritability, confusion and headaches. The other signs of early hypercapnia encompass:
- Flushed skin
- Extra systoles
- Increased blood pressure
- Reduced neural activity
- Muscle twitching
- Loss of consciousness
The basic first aid, one can give a person suffering from high carbon dioxide levels in the blood is by quickly taking the person away from the carbon dioxide source. Then oxygen will be administered to the patient, to elevate oxygen levels in the blood. Most patients recover when the level of oxygen in the arterial blood increases.
Low Levels of Carbon Dioxide in the Blood (Hypocapnia)
While most of us are of the school of thought that oxygen is the useful gas, while CO2 is the waste our body expels, the latter is important as well. Even slight dip in the concentration of CO2 levels in the arterial blood can affect the respiratory pattern of the body. Also known as hypocarbia, hypocapnia refers to the condition of reduced CO2 levels in the arterial bloodstream and is the opposite condition of hypercapnia. This condition is sometimes aroused by the treatment of medical emergencies, such as hyperkalemia, high blood pressure (hypertension), etc. On the other hand, hypocapnia can also be self induced, by hyperventilation.
What Causes Hypocapnia?
The state of breathing faster and deeper than necessary is termed as hyperventilation. Such a condition occurs during physical exercises, wherein, the person breathes through the mouth while exercising. This over-breathing results in light-headedness and several other undesirable symptoms, that are associated with panic attacks. Hyperventilation reduces the CO2 levels in the bloodstream, below the normal 40 mm of Hg, thereby resulting in an increased level of pH value. Since CO2 increases the acidity in the blood, low CO2 level leads to increased alkalinity in the blood. This, in turn, leads to the constriction of blood vessels that supply blood to the brain. Moreover, transport of essential electrolytes for the functioning of the nervous system is also reduced. Low level of CO2 in the bloodstream, can cause cerebral vasoconstriction, thereby resulting in cerebral hypoxia.
Symptoms of Hypercapnia
Mild symptoms pertaining to this condition are constipation, nasal blockage, constant coughing, etc. The other symptoms are:
- Visual disturbances
- Transient dizziness in the person
- Muscle cramps
- Increase in asthma severity
If not treated on time, hypocapnia can conduce to lung damage and various lung diseases. Patients are given training on breathing, so as to avoid such a problem in the future.
Most of the CO2 content in the body is in the form of bicarbonate. Thus, when laboratory tests are conducted to check the CO2 level in the blood, it is actually measuring the blood bicarbonate level. The level of carbon dioxide in the blood has to be around 40 mm of Hg, for the proper functioning of the body. Deviations in the amount of carbon dioxide in blood can lead to dizziness, respiratory and cardiac arrest and even death.
Why is this test done?
This test is done to determine Bicarbonate concentration in blood. When an acid-base imbalance is foreseen, an electrolyte panel and blood gases may be ordered to evaluate the severity of the imbalance, determine whether it is from respiratory origin or metabolic, and monitor its treatment until the acid-base balance is restored.
A carbon dioxide test is often done as part of a group of laboratory blood tests (chemistry screen) to help find the cause of many kinds of symptoms. It is often done if you are having breathing problems.
You do not need to do anything before you have this test. Many medicines may change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean.
The CO2 test is most often done as part of an electrolyte or basic metabolic panel. Changes in your CO2 level may suggest that you are losing or retaining fluid, which causes an imbalance in your body's electrolytes. CO2 levels in the blood are influenced by kidney and lung function. The kidneys are mainly responsible for maintaining the normal bicarbonate levels.
It is important to keep a balance of electrolytes in your body, because they affect the amount of water in your body, blood acidity (pH), muscle action, and other important processes. You lose electrolytes when you sweat, and you must replace them by drinking fluids. Electrolytes exist in the blood as acids, bases, and salts (such as sodium, calcium, potassium, chlorine, magnesium, and bicarbonate). They can be measured by laboratory studies of the blood.
When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.
Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.
The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.
Venous , arterial, or capillary blood:
Before having blood collected, tell the person drawing your blood if you are allergic to latex. Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. Also tell the healthcare worker if you have felt nauseated, lightheaded, or have fainted while having blood drawn in the past.
Umbilical cord blood:
Ask the healthcare worker for information about how to prepare for this test.
How is the test done?
The health professional drawing blood will:
Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
Clean the needle site with alcohol.
Put the needle into the vein. More than one needle stick may be needed.
Attach a tube to the needle to fill it with blood.
Remove the band from your arm when enough blood is collected.
Put a gauze pad or cotton ball over the needle site as the needle is removed.
Put pressure on the site and then put on a bandage.
Before Administering the Test
Assess if the patient:
Has taken corticosteroids, antibiotics, antacids, diuretics, aspirin, sodium bicarbonate, or barbiturates
A sample of blood is taken from the patient's vein. The patient will experience a tight feeling when the tourniquet is tightened, a pinch or nothing at all when the needle is inserted into the vein, and pressure when a gauze pad is pressed against the insertion site to stop bleeding. It can take up to 10 minutes for bleeding to stop if the patient is taking anticoagulants (aspirin, coumadin). A small bruise might appear at the insertion site, which could become swollen following this test. This is called phlebitis. Applying a warm compress several times a day will reduce the swelling.
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
A sample of venous, arterial, capillary or umbilical cord blood may be collected for this test.
Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.
When a blood sample from a vein is needed, a vein in your arm is usually selected. A tourniquet (large rubber strap) may be secured above the vein. The skin over the vein will be cleaned, and a needle will be inserted. You will be asked to hold very still while your blood is collected. Blood will be collected into one or more tubes, and the tourniquet will be removed. When enough blood has been collected, the healthcare worker will take the needle out.
Before an arterial blood draw, the healthcare worker may check blood circulation to your arm or leg. Tell the healthcare worker if you use supplemental oxygen as this may affect the test results.
An artery in the wrist is the most common site to draw arterial blood. However, an artery at the inside bend of the arm or groin may be used. The area will be swabbed clean with antiseptic. Anesthetic may be used to numb the skin over the area where the blood will be drawn. A needle is used to puncture the skin. You will be asked to hold very still while your blood is collected. When enough blood is collected, the needle will be removed.
If you have an existing arterial catheter, a blood sample may be collected from that catheter.
Common sites to collect a capillary blood sample are the fingertip and earlobe. Infants often have a capillary blood sample taken from the heel of the foot. Once the site is selected, the healthcare worker may heat the area with a warm compress to ensure adequate blood flow. The area will be cleaned with antiseptic. A small needle is used to make a cut in the skin surface, and the area may be squeezed gently to produce blood. The blood is collected in small collection device.
Umbilical cord blood:
To collect an umbilical cord blood sample after an infant is born, the healthcare worker may use a needle and syringe to draw blood from the umbilical cord while the cord is still attached to the infant. Blood samples may also be collected from the part of the umbilical cord that has been detached from the infant.
After birth, an infant's body does not need the attached umbilical cord stump or its blood vessels, but they may be used temporarily for medical purposes. If the infant has a catheter inserted in a vessel of the umbilical cord, the blood sample may be collected through the existing catheter.
What should I do after the test?
After a blood sample is collected from your vein, a bandage, cotton ball, or gauze may be placed on the area where the needle was inserted. You may be asked to apply pressure to the area. Avoid strenuous exercise immediately after your blood draw. Contact your healthcare worker if you feel pain or see redness, swelling, or discharge from the puncture site.
If blood was drawn from an artery in your arm or leg, cotton will be placed over the site and held firmly for at least five minutes to stop the bleeding. Bleeding may continue beyond five minutes if you are using medications or supplements that thin your blood or have a medical condition that causes excessive bleeding. When bleeding has stopped, a bandage will be placed firmly over the site and should be left on for 30 to 60 minutes. You should rest for at least 15 minutes after the test. Avoid heavy use of the arm or leg from which the blood was drawn for 24 hours after the blood is collected.
If blood was drawn from an existing catheter inserted into an artery, there are no special instructions for you after this test.
After capillary blood collection is complete, cotton will be placed over the site and held firmly until the bleeding has stopped. A bandage or cotton may be secured over the site.
Umbilical cord blood:
Depending on the procedure used to obtain a sample of cord blood, there may be special instructions for you to follow. Ask the healthcare worker for any special instructions following this procedure.
What does the test result mean?
Reference range values
- Carbon Dioxide, Total: 21 – 31 mmol/L
- Sodium: 135-144 mmol/L
- Potassium: 3.3 - 5.1 mmol/L
- Chloride: 99 – 107 mmol/L
A carbon dioxide test measures the total amount of the three forms of carbon dioxide (bicarbonate, carbonic acid, and dissolved carbon dioxide) in your blood. Results are usually available in 1 to 2 days.
Carbon dioxide content
High values may be caused by:
- Diseases that decrease blood pH (respiratory acidosis), such as chronic obstructive pulmonary disease (COPD), emphysema, and pneumonia.
- Diseases that increase blood pH (metabolic alkalosis), such as Cushing's syndrome, Conn's syndrome, and alcoholism.
Low values may be caused by:
- Problems that increase blood pH (respiratory alkalosis), such as pneumonia, cirrhosis, liver failure, or hyperventilation.
- Problems that decrease blood pH (metabolic acidosis), such as uncontrolled diabetes, kidney or heart failure, aspirin overdose, shock, frequent diarrhea, dehydration, long-term (chronic) starvation, and swallowing antifreeze (ethylene glycol) or wood alcohol (methanol).
Test results are available quickly. The laboratory determines normal values based on calibration of testing equipment with a control test. Test results are reported as high, normal, or low based on the laboratory's control test.
Normal range is:
- Adult: 23 to 29 mmol/L
- Children: 20 to 28 mmol/L
- Under 1 year old: 13 to 22 mmol/L
The normal result of a bicarbonate blood test depends on the age of the individual. For adults, a normal bicarbonate level falls between 23–29 millimoles per liter (mmol/L). Children have a wider range and it falls between 20–28 mmol/L. Infants have the widest range, with normal values falling between 13–22 mmol/L.
There are several factors which may affect the test results including drug interaction. Methicillin, nitrofurantoin, and tetracycline are a few of the medicines which can lower the amount of bicarbonate in the blood. Fludrocortisone, barbiturates, and bicarbonates in contrast increase the amount of bicarbonate in the blood.
High level values may indicate vomiting, pneumonia (respiratory acidosis), COPD (respiratory acidosis), Conn's syndrome (metabolic acidosis), alcoholism (metabolic acidosis), or Cushing's syndrome (metabolic acidosis). Low level values may indicate hyperventilation (respiratory alkalosis), cirrhosis (respiratory alkalosis), liver failure (respiratory alkalosis), pneumonia (respiratory alkalosis), diabetes (metabolic alkalosis), aspirin overdose (metabolic alkalosis), diarrhea (metabolic alkalosis), heart failure (metabolic alkalosis), kidney failure (metabolic alkalosis), chronic starvation (metabolic alkalosis), ingestion of antifreeze (metabolic alkalosis), or ingestion of methanol (metabolic alkalosis).
Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. If your results are different from the results suggested below, this may not mean that you have a disease. Contact your healthcare worker if you have any questions. The following are considered to be normal results for this test:
- Adults, plasma, at sea level: 21-30 mEq/L (21-30 mmol/L)
- Adults, capillary (heparin) plasma: 22-28 mEq/L (22-28 mmol/L)
- Adults, whole blood, arterial: 19-24 mEq/L (19-24 mmol/L)
- Adults, whole blood, venous: 22-26 mEq/L (22-26 mmol/L)
- Adults over 60 years, plasma or serum, venous: 23-31 mEq/L (23-31 mmol/L)
- Adults over 90 years, plasma or serum, venous: 20-29 mEq/L (20-29 mmol/L)
- Premature, 1 week, capillary (heparin) plasma: 14-27 mEq/L (14-27 mmol/L)
- Newborn, capillary (heparin) plasma: 13-22 mEq/L (13-22 mmol/L)
- Cord blood: 14-22 mEq/L (14-22 mmol/L)
- Infant, capillary (heparin) plasma: 20-28 mEq/L (20-28 mmol/L)
- Child, capillary (heparin) plasma: 20-28 mEq/L (20-28 mmol/L)
What if the test result is not normal?
Possible causes of a low bicarbonate level include:
- Addison’s disease
- Chronic diarrhea
- Diabetic ketoacidosis
- Metabolic acidosis
- Kidney disease
- Ethylene glycol or methanol poisoning
- Salicylate (aspirin) overdose
- Possible causes of high levels are:
- Severe vomiting
- Lung diseases
- Cushing’s syndrome
- Conn’s syndrome
- Metabolic alkalosis
There is very little chance of a problem from having blood sample taken from a vein.
- You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
- In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
- Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.
Reasons you may not be able to have the test or why the results may not be helpful include:
- Taking medicine, such aspirin, antacids, some antibiotics, corticosteroids, diuretics, barbiturates, sodium bicarbonate, or high doses of steroid hormones.
- Having a high body temperature (hyperthermia).
- Many medicines may change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.
Lower-than-normal levels may be due to:
- Addison disease
- Ethylene glycol poisoning
- Kidney disease
- Lactic acidosis
- Metabolic acidosis
- Methanol poisoning
- Salicylate toxicity (such as aspirin overdose)
Higher-than-normal levels may be due to:
- Breathing disorders
- Cushing syndrome
The following conditions may also alter bicarbonate levels:
- Renal tubular acidosis; distal
- Renal tubular acidosis; proximal
What are the risks?
Blood: During a blood draw, a hematoma (blood-filled bump under the skin) or slight bleeding from the puncture site may occur. After a blood draw, a bruise or infection may occur at the puncture site. The person doing this test may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of this test.
Arterial blood: During an arterial blood draw, a hematoma (blood-filled bump under the skin) or slight bleeding from the puncture site may occur. After a blood draw, a bruise or infection may occur at the puncture site. The person doing this test may need to perform it more than once.
If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the puncture site. Rarely, damage to the artery that affects blood flow to the arm or the leg may occur. Talk to your healthcare worker if you have any concerns about the risks of this test.
Umbilical cord blood: After the baby is born, umbilical cord blood may be collected in two ways. One method is to collect blood from the portion of the umbilical cord that is not attached to the baby. This method carries no risks. Umbilical cord blood may also be collected from a catheter which may be inserted into the baby’s umbilical artery or vein for medical purposes. Risks of collecting umbilical cord blood using this method include blood loss, infection, and air bubbles in the blood vessels. Additionally, a blood vessel spasm may occur, temporarily decreasing blood flow to a part of the baby’s body. The person doing this procedure may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of having umbilical cord blood collected using this method.