What are the three blood variables considered when making a diagnosis of acidosis?

What are Acidosis and Alkalosis?

Acidosis and alkalosis are conditions in which there is a disturbance in the pH balance (acid-base balance) of the body. Acidosis is a condition in which the bodily fluids become too acidic, with an abnormally low pH level. In alkalosis, the opposite is true: the fluids of the body are too alkaline (high in pH).

Inhaltsverzeichnis Show

What are Acidosis and Alkalosis?
Acid-Base Balance in the Body
Staying in Balance
Acid Buildup
Neutralizing and Removing Acids
How the Body Maintains Acid-Base Balance
Lung Functions that Correct Imbalances
Kidney Functions that Correct Imbalances
How Things Can Go Wrong
Metabolic vs Respiratory Acidosis and Alkalosis
Common causes of acidosis
Common causes of alkalosis
Mixed acid-base imbalances
Testing for Acidosis and Alkalosis
Understanding acidosis and alkalosis test results
Additional testing
Non-lab tests
Treatment of Acidosis and Alkalosis
Treatment of acidosis
Treatment of alkalosis
Related Content
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What are the three blood variables considered when making a diagnosis of acidosis or alkalosis?
What blood test shows acidosis?
How is acidity in blood measured?
What blood test is used to determine if a patient has an acid

Acid-Base Balance in the Body

pH is a way of measuring the acidity or alkalinity of a fluid, on a scale from 1 to 14. A pH of 7 is considered neutral, while 1 is extremely acidic, and 14 is extremely alkaline, which is sometimes called “basic”. Normally, the pH of the human body is around 7.4, which is slightly higher than the chemically-neutral pH of 7. This slightly alkaline pH is ideal for many crucial processes that take place continually in the human body.

For instance, normal pH and proper acid-base balance enables the right amount of oxygen to enter and circulate in the blood, moving oxygen to all the cells and tissues of the body. Proteins, including enzymes, which speed up many chemical actions in the body, can’t function normally if body fluids are too acidic.

Acidosis

Acidosis occurs when bodily fluids contain too much acid. This results in a decrease in blood pH, since lower numbers represent more acidic substances. The blood is considered to be abnormally acidic (high in acid) when its pH is lower than 7.35.

Mild acidosis may be present without causing symptoms. In some cases, especially in seriously ill people, it can worsen if it is not diagnosed and treated. Acidosis can sometimes lead to serious physical effects, such a:

Hyperventilation (breathing abnormally fast or deeply)
Impaired heart function
Low blood pressure
Coma

Alkalosis

Alkalosis is a condition in which the blood has too little acid, making it too alkaline or basic, which is another term for alkaline. This results in a higher blood pH, as higher numbers represent more alkaline substances. The blood is considered to be abnormally alkaline when its pH is above 7.45.

Mild, longstanding (chronic) alkalosis may occur without noticeable symptoms. Alkalosis that causes severe or rapid pH changes is more likely to cause symptoms that can include:

Dizziness or lightheadedness
Numbness of the hands and feet
Confusion
Nausea or vomiting
Muscle twitching or spasms
Low levels of oxygen in the blood
Seizures
Losing consciousness or being nearly unconscious

Staying in Balance

The normal pH of the human body ranges from 7.35 to 7.45, with 7.4 being average.

The body constantly engages in a number of activities to maintain pH within this narrow range. Under normal circumstances, the level of acids and bases in the body may rise and fall, as more acids and bases are produced or taken in. Processes in the body are always at work to adjust for these changes and keep the acid-base balance within the normal range.

Acid Buildup

Our bodies constantly produce acids during the normal processes of metabolism. Metabolism means all of the chemical and physical processes that our bodies use to generate energy and to produce substances necessary to maintain life. For example, our bodies convert nutrients in our food like fats, carbohydrates, and proteins into energy. The processes of metabolism normally generate large quantities of acids during these ongoing activities.

Most of the acid in our bodies is carbonic acid. The metabolism of fats and carbohydrates generates carbon dioxide which combines with water in the body to form carbonic acid. Other acids produced by the body include:

Lactic acid: This acid is mainly produced in muscle cells and red blood cells when the body metabolizes carbohydrates and oxygen levels are low, such as during intense exercise.
Ketoacids or ketones: These acids are formed by the breakdown of fats when the body’s main source of energy, glucose (sugar), is in short supply or when there is a lack of insulin, which is necessary for using glucose for energy.

Neutralizing and Removing Acids

Specialized cells in the brain and blood vessels sense the body’s acidity, and control processes that neutralize and remove acids. This feedback loop is essential to maintaining the body’s acid-base balance. Maintaining balance is crucial because even small changes can severely affect many organs and disrupt the way the cells of the body function.

The different mechanisms that the body uses to continually neutralize and remove acids and maintain pH balance include:

Breathing out carbon dioxide, which reduces acid in the body
Release of acid in urine
Regulating body pH through chemical buffering. Circulating weak acids and weak bases in the blood guard against abrupt changes in acidity and alkalinity.

How the Body Maintains Acid-Base Balance

The body automatically adjusts when it notices an imbalance in pH. The mechanisms it uses push the acid-base balance back toward the ideal pH range. The main organs involved in these processes are the lungs and the kidneys.

Lung Functions that Correct Imbalances

The lungs respiratory system responds to changes in acid-base balance caused by the body’s metabolic processes. Carbon dioxide, when combined with water, forms an acid (carbonic acid). When you breathe out, carbon dioxide is removed from your body into the environment and your body removes acids that have been produced by metabolism. Your respiratory system automatically adjusts your breathing rate and the amount of air that moves out of the lungs. This ensures you exhale the right amount of carbon dioxide based on how much acid your tissues are producing.

For example, in diabetic ketoacidosis, low levels of insulin force the body to break down fats for energy use, in place of using glucose that requires insulin. Breakdown of fat produces excess ketoacids, which lower the body’s pH. The breathing rate increases to get rid of carbon dioxide. When carbon dioxide is removed from the body at a faster rate, the level of acid in the body drops, and the pH starts to return toward the normal range.

The lungs also can also adjust when blood pH is too high. For example, if someone loses stomach acid due to vomiting, the blood pH can rise. The breathing rate will slow and less carbon dioxide will be removed through breathing. This drives the body’s pH lower, toward the normal range.

Kidney Functions that Correct Imbalances

Your kidneys also play a critical role in maintaining your body’s pH. Generally, the kidneys respond with acid-base imbalances from conditions that affect the lungs.

The kidneys help maintain normal pH balance by increasing the amount of acid released in the urine when the body’s pH level is too low (acidic), and retaining bicarbonate, which is a base (alkaline substance). This drives the pH higher toward the normal range.

Conversely, when the body’s pH is too high (alkaline), the kidneys increase the amount bicarbonate released in the urine, and retain acid to lower the pH back toward the normal range.

The pH of urine shifts up or down as the kidneys adjust to blood acidity or alkalinity.

How Things Can Go Wrong

Although the body can generally maintain pH balance, some conditions can overwhelm the body’s ability to react to an imbalance. Acid-base imbalances can also occur when lung or kidney disorders affect the ability of these organs to control for pH imbalances.

Metabolic vs Respiratory Acidosis and Alkalosis

Acidosis and alkalosis are categorized according to whether they are caused by metabolic (related to basic bodily processes) versus respiratory (lung) problems. Understanding and determining the cause of the imbalance is important in helping to guide treatment of the pH imbalance.

The categories of acidosis are:

Metabolic acidosis: Metabolic acidosis occurs when too much acid is produced by the body, or too much bicarbonate, which is a base (alkali), is lost. Also, taking in certain substances or poisons that are acidic or become acidic in the body can overwhelm the body’s mechanisms and cause metabolic acidosis.
Respiratory acidosis: Respiratory acidosis occurs when lung or breathing disorders affect the body’s ability to breathe out carbon dioxide, leading to too much acid in the body.

The categories of alkalosis are:

Metabolic alkalosis: Metabolic alkalosis may be caused by losing too much acid from the body, or by having too much bicarbonate.
Respiratory alkalosis: Respiratory alkalosis can happen when there is too little carbon dioxide in the blood due to the lungs breathing out too much carbon dioxide. This may be due to hyperventilating, which is breathing abnormally fast, or conditions that cause shortness of breath.

The following table summarizes how the body works to adjust for acid-base imbalances:

pH	Condition	The body compensates by:
Low	Metabolic acidosis	Breathing faster to exhale more CO2
High	Metabolic alkalosis	Breathing slower to exhale less CO2
Low	Respiratory acidosis	The kidneys retaining more bicarbonate and releasing more acid into urine
High	Respiratory alkalosis	The kidneys retaining more acid and releasing more bicarbonate into urine

Common causes of acidosis

The table below provides examples of common causes of acidosis:

Common Causes of Metabolic Acidosis
Cause	Examples of How Things Can Go Wrong
Poisoning	May occur when a substance that is acidic, or is metabolized to acid in the body, is swallowed, such as methanol or antifreeze, or large amounts of aspirin
Ketoacidosis	May occur when the body does not make enough insulin to metabolize sugar for energy. Instead, more fats and proteins are metabolized, which results in too many ketoacids for the body to process.
Alcoholic Ketoacidosis	May occur with very heavy alcohol use and not eating enough food, which can lead to the body burning more fat than usual.
Lactic Acidosis	Occurs when lactic acid builds up in the bloodstream. Severe illnesses can cause lactic acidosis when blood pressure is low and not enough oxygen gets to tissues. Examples of causes include sepsis due to a serious bacterial infection, cancer and liver failure.
Kidney Failure/Kidney Disease	Occurs when the kidneys are not functioning properly and are unable to remove enough acid to maintain normal pH. May also occur if kidney disease causes loss of bicarbonate, an alkaline substance that normally neutralizes acid in the body.
Severe, Prolonged Diarrhea	May lead to loss of bicarbonate, which normally neutralizes acid in the body
Common Causes of Respiratory Acidosis
Cause	Examples of How Things Can Go Wrong
Lung Diseases	May cause acid buildup in the body when breathing is impaired, and not enough carbon dioxide is exhaled. May be caused by conditions such as asthma, chronic obstructive pulmonary disease (COPD), sleep apnea, or swelling of the airways.
Central nervous system diseases	These diseases can interfere with normal breathing and not enough carbon dioxide is exhaled.
Drugs	Certain drugs, such as narcotics and barbiturates, can slow the breathing rate and result in excess carbon dioxide.
Blocked airways	This can affect the amount of carbon dioxide that is expelled.

Common causes of alkalosis

The table below provides examples of common causes of alkalosis:

Common Causes of Metabolic Alkalosis
Cause	Examples of How Things Go Wrong
Kidney (renal) problems	Metabolic alkalosis may occur if the kidneys release too much acid into the urine.
Excess loss of fluids and minerals	This can be caused by severe dehydration or use of diuretics, which are medications that promote removal of fluid from the body.
Severe, prolonged vomiting	Prolonged vomiting may lead to the loss of too much stomach acid, causing alkalosis.
Poisoning	Although it is rare, metabolic alkalosis may develop if someone swallows too much base from an alkaline substance like baking soda.
Common Causes of Respiratory Alkalosis
Hyperventilation (Breathing abnormally fast or deeply)	May lead to excessive loss of acid from the body through exhaling too much carbon dioxide. Hyperventilation can be due to anxiety or pain or may be a physical response to lack of oxygen or shock, which occurs when tissues are not getting enough blood. Hyperventilation can also occur with medical problems such as fever, infection, or bleeding.
Shortness of breath, difficulty breathing	May be caused by asthma, pneumonia, lung congestion due to heart failure, or a pulmonary embolism, which is a blocked blood vessel in the lung

Mixed acid-base imbalances

More than one acid-base imbalance can occur at the same time. This is called a mixed acid-base disorder or a complex acid-base disturbance. Mixed disorders happen when a patient has a condition that causes one type of imbalance then a second type of imbalance occurs.

For example, a patient with an alcohol abuse disorder may develop ketoacidosis due to alcohol misuse and metabolic alkalosis due to vomiting with loss of stomach acid. The ketoacidosis increases the acidity of body fluids at the same time the loss of stomach acid decreases acidity.

Another example of a mixed acid-base disorder may occur due to aspirin poisoning. Aspirin triggers increased breathing, which can lead to respiratory alkalosis due to hyperventilating. At the same time, aspirin is an acid, and large doses often cause metabolic acidosis.

Mixed acid-base disturbances may result in misleading test results that seem normal. Health care providers must carefully review laboratory test results to determine whether a single or mixed acid-base imbalance is present.

Testing for Acidosis and Alkalosis

When an acid-base imbalance is suspected, your health care provider will evaluate your vital signs, including blood pressure, breath rate, pulse, and temperature, and order tests to help diagnose or rule it out. If acidosis or alkalosis is detected, you may also have additional tests to determine its cause. Some people may have testing for acidosis or alkalosis to follow up on abnormal results on a common screening test, such as a complete metabolic panel (CMP).

Main tests

Diagnosis is typically based on the results of the following tests:

Blood gases: Blood gases are a group of tests performed on a blood sample that is usually collected from an artery, instead of a vein. Arteries are the blood vessels which carry blood from the heart to the rest of the body. Measurements of blood pH from an artery generally better reflect what is going on in the body than blood from a vein. Blood gases provide measurements that are important for the diagnosis of acidosis and alkalosis:
- Blood pH
- Carbon dioxide level, also called partial pressure of CO2, PaCO2 or PCO2
- Oxygen level, also called partial pressure of O2, PaO2 or P02
- Oxygen saturation, also called O2 Sat: determines oxygen levels based on measuring levels of hemoglobin. Hemoglobin is the protein in red blood cells that is responsible for carrying oxygen throughout the body.
- Bicarbonate
Electrolytes and anion gap: These tests measure minerals in the blood, including sodium, potassium, chloride, and bicarbonate.Your health care team can use the results of this test to calculate your anion gap, which helps them narrow down the cause of acidosis and distinguish between anion-gap and non-anion-gap metabolic acidosis. Electrolytes may be measured by themselves, or as part of a Basic Metabolic Panel (BMP) or a Comprehensive Metabolic Panel (CMP).

Understanding acidosis and alkalosis test results

Blood gas results are interpreted in the context of your symptoms and history, as well as results from other tests performed at the same time.

Examples of test results associated with the four main acidosis and alkalosis conditions are provided in this table.

pH	Bicarbonate	Carbon Dioxide (PCO2)	Condition
Low	Low	Low	Metabolic acidosis
High	High	High	Metabolic alkalosis
Low	High	High	Respiratory acidosis
High	Low	Low	Respiratory alkalosis

Additional testing

Additional testing may be done to understand the cause of acidosis or alkalosis. This is important because treatment typically is directed at the underlying cause. Testing may include one or more of the following, depending on the suspected cause:

Test	Sample Type	Why Test is Performed
Glucose testing	Blood or urine	High blood sugar or sugar in urine may reveal undiagnosed or untreated diabetes as cause of acidosis
Ketones	Urine or blood	Elevated level may help diagnose ketoacidosis
Lactate	Blood	High levels of lactic acid (lactate) indicate lactic acidosis
Blood Urea Nitrogen (BUN)	Blood	This test helps evaluate how well the kidneys are working
Creatinine	Blood	Another test that indicates how well the kidneys are working
Alcohol Testing	Blood	Can help detect alcohol poisoning; an expanded alcohol panel may also measure blood levels of methanol and ethylene glycol
Drug Testing	Blood or urine	May detect drugs that reduce breathing and can lead to respiratory acidosis
Salicylate Acid (Aspirin) Testing	Blood	High blood levels of salicylates (aspirin) may cause acidosis
Osmolality and Osmolal Gap	Blood or urine	May reveal imbalances due to poisoning from methanol or ethylene glycol
Complete blood test (CBC)	Blood	Evaluates blood cells; may reveal, for example, a serious infection
Urinalysis	Urine	Measures levels of protein, glucose (sugar), ketones, and urine pH; may provide diagnostic clues about the cause of imbalance

Non-lab tests

Patients who are undergoing evaluation for acidosis and alkalosis may also have some of the following non-lab tests performed to determine what might be the underlying cause:

Chest X-ray
CT scan of the chest
Pulmonary function tests
Electrocardiogram

Treatment of Acidosis and Alkalosis

Treatment of both acidosis and alkalosis is almost always directed at reversing the cause of the disorder. It is rare for alkaline or acid substances to be given to restore balance.

Treatment of acidosis

How acidosis is treated will depend on what is causing it. For example, in metabolic acidosis caused by untreated diabetes, therapy may be directed at controlling blood sugar with insulin. If acidosis is caused by breathing problems, treatment aims at improving lung function. If breathing is severely impaired, mechanical ventilation may be needed.

Treatment of alkalosis

Metabolic alkalosis may be treated by giving fluids and electrolytes while treating the cause of fluid loss. Respiratory alkalosis is treated by ensuring the patient has sufficient oxygen and treating the underlying cause of hyperventilating, such as an infection, pain, or anxiety.

Electrolytes and Anion Gap Learn More
Sodium Learn More
Potassium Learn More
Chloride Blood Test Learn More
Bicarbonate (Total CO2) Learn More
Blood Gases Learn More
Osmolality and Osmolal Gap Learn More
MedlinePlus Medical Encyclopedia: Acidosis Learn More
MedlinePlus Medical Encyclopedia: Alkalosis Learn More
National Kidney Foundation: Metabolic Acidosis Learn More
MedlinePlus Medical Encyclopedia: Lactic acidosis Learn More
American Diabetes Association: DKA (Ketoacidosis) & Ketones Learn More
MedlinePlus Medical Encyclopedia: Diabetic ketoacidosis Learn More
American Lung Association Learn More
MedlinePlus Medical Encyclopedia: Hyperventilation Learn More

Sources

A.D.A.M. Medical Encyclopedia. BUN blood test. Updated April 29, 2019. Accessed December 1, 2021. https://medlineplus.gov/ency/article/003474.htm

A.D.A.M. Medical Encyclopedia. Lactic acid test. Updated April 29, 2019. Accessed November 24, 2021. https://medlineplus.gov/ency/article/003507.htm

A.D.A.M. Medical Encyclopedia. Creatinine blood test. Updated July 4, 2019. Accessed December 1, 2021. https://medlineplus.gov/ency/article/003475.htm

A.D.A.M. Medical Encyclopedia. Acidosis. Updated September 24, 2019. Accessed November 23, 2021. https://medlineplus.gov/ency/article/001181.htm

A.D.A.M. Medical Encyclopedia. Alkalosis. Updated November 2, 2021. Accessed November 23, 2021. https://medlineplus.gov/ency/article/001183.htm

A.D.A.M. Medical Encyclopedia. Electrolytes. Updated September 24, 2019. Accessed December 2, 2021. https://medlineplus.gov/ency/article/002350.htm

A.D.A.M. Medical Encyclopedia. Metabolic acidosis. Updated September 24, 2019. Accessed November 24, 2021. https://medlineplus.gov/ency/article/000335.htm

A.D.A.M. Medical Encyclopedia. Diabetic ketoacidosis. Updated January 26, 2020. Accessed December 17, 2021 .https://medlineplus.gov/ency/article/000320.htm

A.D.A.M. Medical Encyclopedia. Metabolism. Updated July 13, 2020. Accessed November 24, 2021. https://medlineplus.gov/ency/article/002257.htm

A.D.A.M. Medical Encyclopedia. Blood gases. Updated August 3, 2020. Accessed November 28, 2021. https://medlineplus.gov/ency/article/003855.htm

A.D.A.M. Medical Encyclopedia. Respiratory alkalosis. Updated August 3, 2020. Accessed November 24, 2021. https://medlineplus.gov/ency/article/000111.htm

A.D.A.M. Medical Encyclopedia. Hyperventilation. Updated August 13, 2020. Accessed December 1, 2021. https://medlineplus.gov/ency/article/003071.htm

A.D.A.M. Medical Encyclopedia. Lactic acidosis. Updated October 11, 2020. Accessed December 1, 2021. https://medlineplus.gov/ency/article/000391.htm

A.D.A.M. Medical Encyclopedia. CBC blood test. Updated October 16, 2020. Accessed December 5, 2021. https://medlineplus.gov/ency/article/003642.htm

A.D.A.M. Medical Encyclopedia. Vital signs. Updated January 16, 2021. Accessed November 29, 2021. https://medlineplus.gov/ency/article/002341.htm

American Board of Internal Medicine. ABIM laboratory test reference ranges. Updated July 2021. Accessed December 1, 2021. https://www.abim.org/Media/bfijryql/laboratory-reference-ranges.pdf

American Diabetes Association. DKA (Ketoacidosis) & ketones. Date unknown. Accessed November 24, 2021. https://www.diabetes.org/diabetes/complications/dka-ketoacidosis-ketones

Boyer EW, Weitbrecht KW. Salicylate (aspirin) poisoning in adults. In: Traub SJ, ed. UpToDate. Updated June 23, 2021. Accessed December 1, 2021. https://www.uptodate.com/contents/salicylate-aspirin-poisoning-in-adults

Brutsaert EF. Diabetic ketoacidosis (DKA). Merck Manuals Professional Version. Updated September 2020. Accessed November 29, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/diabetes-mellitus-and-disorders-of-carbohydrate-metabolism/diabetic-ketoacidosis-dka

Burger M, Schaller DJ. Metabolic acidosis. In: StatPearls. Updated July 26, 2021. Accessed November 24, 2021. https://www.ncbi.nlm.nih.gov/books/NBK482146/

Cheng S, Schindler E, Scott M. Acid-Base Physiology and Conditions Associated with Abnormal Acid-Base Status and Abnormal Electrolyte Composition of the Blood, Chap 60. In: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, Sixth Edition. Ed. Nader Rifai, PhD. 2018 by Elsevier, Inc.

Chung PH. Urinalysis and urine culture. Merck Manual Consumer Version. Updated May 2020. Accessed December 1, 2021. https://www.merckmanuals.com/home/kidney-and-urinary-tract-disorders/diagnosis-of-kidney-and-urinary-tract-disorders/urinalysis-and-urine-culture

Danckers M, Fried ED. Arterial blood gas sampling. In: Rowe VL, ed. Medscape. Updated May 8, 2020. Accessed December 1, 2021. https://emedicine.medscape.com/article/1902703-overview

Emmett M, Szerlip H. Causes of metabolic acidosis. In: Sterns RH, ed. UpToDate. Updated November 20, 2019. Accessed November 23, 2021. https://www.uptodate.com/contents/causes-of-metabolic-alkalosis

Emmett ME, Szerlip H. Approach to the adult with metabolic acidosis. In: Sterns RH, ed. UpToDate. Updated June 9, 2020. Accessed November 23, 2021. https://www.uptodate.com/contents/approach-to-the-adult-with-metabolic-acidosis

Emmett M, Palmer BF. Simple and mixed acid-base disorders. UpToDate. Updated September 9, 2020. Accessed December 1, 2021. https://www.uptodte.com/contents/simple-and-mixed-acid-base-disorders

Emmett M, Palmer BF. Serum osmolal gap. In: Sterns RH, ed. UpToDate. Updated September 16, 2020. Accessed December 1, 2021. https://www.uptodate.com/contents/serum-osmolal-gap

Emmet M, Szerlip H. Approach to the adult with metabolic acidosis. In: Sterns RH, ed. UpToDate. Updated November 23, 2021. Accessed November 29, 2021.

Gill RS. Respiratory acidosis. In: Mosenifar Z, ed. Medscape. Updated November 6, 2019. Accessed November 23, 2021. https://emedicine.medscape.com/article/301680-overview

Gunnerson KJ, Harvey CE. Lactic acidosis. In: Pinsky MR, ed. Medscape. Updated September 11, 2020. Accessed November 24, 2021. https://emedicine.medscape.com/article/167027-overview

Hirsch IB, Emmet M. Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Clinical features, evaluation, and diagnosis. In: Nathan DM, ed. UpToDate. Updated March 29, 2020. Accessed December 1, 2021. https://www.uptodate.com/contents/diabetic-ketoacidosis-and-hyperosmolar-hyperglycemic-state-in-adults-clinical-features-evaluation-and-diagnosis

Hopkins E, Sanvictores T, Sharma S. Physiology, acid base balance. In: Statpearls. Updated September 14, 2021. Accessed November 23, 2021. https://www.ncbi.nlm.nih.gov/books/NBK507807/

Levine MD. General approach to drug poisoning in adults. In: Traub SJ, ed. UpToDate. Updated July 19, 2021. Accessed November 29, 2021. https://www.uptodate.com/contents/general-approach-to-drug-poisoning-in-adults

Lewis JL. Acid-base disorders. Merck Manual Professional Version. Updated July 2021. Accessed November 24, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/acid-base-disorders

Lewis JL. Acid-base regulation. Merck Manual Professional Version. Updated July 2021. Accessed November 25, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/acid-base-regulation

Lewis JL. Acidosis. Merck Manual Consumer Version. Updated July 2021. Accessed December 1, 2021. https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/acid-base-balance/acidosis

Lewis JL. Alkalosis. Merck Manual Consumer Version. Updated July 2021. Accessed December 1, 2021. https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/acid-base-balance/alkalosis

Lewis JL. Metabolic acidosis. Merck Manuals Professional Version. Updated July 2021. Accessed December 1, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/metabolic-acidosis

Lewis JL. Metabolic alkalosis. Merck Manuals Professional Version. Updated July 2021. Accessed December 2, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/metabolic-alkalosis

Lewis JL. Overview of acid-base balance. Merck Manuals Consumer Version. Updated July 2021. Accessed November 24, 2021. https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/acid-base-balance/overview-of-acid-base-balance

Lewis JL. Respiratory acidosis. Merck Manuals Professional Version. Updated July 2021. Accessed November 29, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/respiratory-acidosis

Lewis JL. Respiratory alkalosis. Merck Manuals Professional Version. Updated July 2021. Accessed November 29, 2021. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/acid-base-regulation-and-disorders/respiratory-alkalosis

Lone NA, Bethuel NW, Whitney L. Respiratory acidosis. In: Mosenifar Z, ed. Medscape. Updated August 27, 2021. Accessed December 1, 2021. https://emedicine.medscape.com/article/301574-overview

MedlinePlus: National Library of Medicine. Gas exchange video. Updated July 25, 2020. Accessed November 24, 2021. https://medlineplus.gov/ency/anatomyvideos/000059.htm

MedlinePlus: National Library of Medicine. Anion gap blood test. Updated July 30, 2020. https://medlineplus.gov/lab-tests/anion-gap-blood-test/

MedlinePlus: National Library of Medicine. Cortisol test. Updated Jul 31, 2020. Accessed November 29, 2021. https://medlineplus.gov/lab-tests/cortisol-test/

MedlinePlus: National Library of Medicine. Renin test. Updated August 9, 2021. Accessed November 29, 2021. https://medlineplus.gov/lab-tests/renin-test/

MedlinePlus: National Library of Medicine. Comprehensive metabolic panel (CMP). Updated September 9, 2021. Accessed December 1, 2021. https://medlineplus.gov/lab-tests/comprehensive-metabolic-panel-cmp/

MedlinePlus: National Library of Medicine. Salicylates level test. Updated September 16, 2021. Accessed November 29, 2021. https://medlineplus.gov/lab-tests/salicylates-level/

Mehta A, Emmett, M. Fasting ketosis and alcoholic ketoacidosis. In: Sterns RH, Traub SJ, eds. UpToDate. Updated October 14, 2020. Accessed November 29, 2021. https://www.uptodate.com/contents/fasting-ketosis-and-alcoholic-ketoacidosis

National Heart, Lung, and Blood Institute. How the lungs work. Updated October 6, 2020. Accessed November 24, 2021. https://www.nhlbi.nih.gov/health-topics/how-lungs-work

National Institute of Diabetes and Digestive and Kidney Diseases. Renal tubular acidosis. Updated November 2020. Accessed November 24, 2021. https://www.niddk.nih.gov/health-information/kidney-disease/renal-tubular-acidosis

National Kidney Foundation. Metabolic acidosis. Updated January 22, 2021. Accessed November 24, 2021. https://www.kidney.org/atoz/content/metabolic-acidosis

Pandey DG, Sharma S. Biochemistry, anion gap. In: StatPearls. Updated July 18, 2021. Accessed December 1, 2021. https://www.ncbi.nlm.nih.gov/books/NBK539757/

Theodore, AC. Arterial blood gases. In: Manaker S, ed. UpToDate. Updated September 29, 2020. Accessed December 1, 2021. https://www.uptodate.com/contents/arterial-blood-gases

Thomas CP. Metabolic acidosis. In: Vatuman V, ed. Medscape. Updated December 8, 2020. Accessed November 23, 2021. https://emedicine.medscape.com/article/242975-overview

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What are the three blood variables considered when making a diagnosis of acidosis or alkalosis?

These variables are carbon dioxide, relative electrolyte concentrations, and total weak acid concentrations. All changes in blood pH, in health and in disease, occur through changes in these three variables.

What blood test shows acidosis?

The anion gap blood test shows whether your electrolytes are out of balance or if your blood is too acidic or not acidic enough. Too much acid in the blood is called acidosis.

How is acidity in blood measured?

There are two main types of tests that doctors can use to find out the pH of someone's blood: arterial blood gas testing and electrolyte testing. Knowing the pH of a person's blood can help a doctor find out if that person has an acid-base disorder.

What blood test is used to determine if a patient has an acid

To detect an acid-base disturbance, both a blood gas analysis and chemistry panel should be performed. This combines traditional blood gas analysis (Henderson-Hasselback equation) and the strong ion approach (by evaluating the contributions of electrolytes, in particular).