Creatine phosphokinase test

CPK test

Creatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle. This article discusses the test to measure the amount of CPK in the blood.

How the Test is Performed

A blood sample is needed. This may be taken from a vein. The procedure is called a venipuncture .

This test may be repeated over 2 or 3 days if you are a patient in the hospital.

How to Prepare for the Test

No special preparation is needed most of the time.

Tell your health care provider about any medicines you are taking. Drugs that can increase CPK measurements include amphotericin B, certain anesthetics, statins, fibrates, dexamethasone, alcohol, and cocaine.

How the Test will Feel

You may feel slight pain when the needle is inserted to draw blood. Some people feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

When the total CPK level is very high, it most often means there has been injury or stress to muscle tissue, the heart, or the brain.

Muscle tissue injury is most likely. When a muscle is damaged, CPK leaks into the bloodstream. Finding which specific form of CPK is high helps determine which tissue has been damaged.

This test may be used to:

• Diagnose heart attack
• Evaluate cause of chest pain
• Determine if or how badly a muscle is damaged
• Detect dermatomyositis , polymyositis , and other muscle diseases
• Tell the difference between malignant hyperthermia and postoperative infection

The pattern and timing of a rise or fall in CPK levels can be significant in making a diagnosis. This is particularly true if a heart attack is suspected.

In most cases other tests are used instead of or with this test to diagnose a heart attack.

Normal Results

Total CPK normal values:

• 10 to 120 micrograms per liter (mcg/L)

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

What Abnormal Results Mean

High CPK levels may be seen in people who have:

• Brain injury or stroke
• Convulsions
• Delirium tremens
• Dermatomyositis or polymyositis
• Electric shock
• Heart attack
• Inflammation of the heart muscle (myocarditis)
• Lung tissue death (pulmonary infarction)
• Muscular dystrophies
• Myopathy
• Rhabdomyolysis

Other conditions that may give positive test results include:

• Hypothyroidism
• Hyperthyroidism
• Pericarditis following a heart attack

Risks

Risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Considerations

Other tests should be done to find the exact location of muscle damage.

Factors that may affect test results include cardiac catheterization , intramuscular injections, trauma to muscles, recent surgery, and heavy exercise.

CPK isoenzymes test

Creatine phosphokinase – isoenzymes; Creatine kinase – isoenzymes; CK – isoenzymes

The CPK isoenzymes test measures the different forms of creatine phosphokinase (CPK) in the blood. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle.

How the Test is Performed

A blood sample is needed. This may be taken from a vein. The test is called a venipuncture .

If you are in the hospital, this test may be repeated over 2 or 3 days. A significant rise or fall in the total CPK or CPK isoenzymes can help your health care provider diagnosis certain conditions.

How to Prepare for the Test

No special preparation is needed in most cases.

Tell your provider about all the medicines you are taking. Some drugs can interfere with test results. Drugs that can increase CPK measurements include the following:

• Alcohol
• Amphotericin B
• Certain anesthetics
• Cocaine
• Fibrate drugs
• Statins
• Steroids, such as dexamethasone

This list is not all-inclusive.

How the Test Will Feel

You may feel slight pain when the needle is inserted to draw blood. Some people feel or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

This test is done if a CPK test shows that your total CPK level is elevated. CPK isoenzyme testing can help find the exact source of the damaged tissue.

CPK is made of three slightly different substances:

• CPK-1 (also called CPK-BB) is found mostly in the brain and lungs
• CPK-2 (also called CPK-MB) is found mostly in the heart
• CPK-3 (also called CPK-MM) is found mostly in skeletal muscle

What Abnormal Results Mean

Higher-than-normal CPK-1 levels:

Because CPK-1 is found mostly in the brain and lungs, injury to either of these areas can increase CPK-1 levels. Increased CPK-1 levels may be due to:

• Brain cancer
• Brain injury (due to any type of injury including, stroke, or bleeding in the brain)
• Electroconvulsive therapy
• Pulmonary infarction
• Seizure

Higher-than-normal CPK-2 levels:

CPK-2 levels rise 3 to 6 hours after a heart attack . If there is no further heart muscle damage, the level peaks at 12 to 24 hours and returns to normal 12 to 48 hours after tissue death.

Increased CPK-2 levels may also be due to:

• Electrical injuries
• Heart defibrillation (purposeful shocking of the heart by medical personnel)
• Heart injury (for instance, from a car accident)
• Inflammation of the heart muscle usually due to a virus (myocarditis)
• Open heart surgery

Higher-than-normal CPK-3 levels are most often a sign of muscle injury or muscle stress. They may be due to:

• Crush injuries
• Muscle damage due to drugs or being immobile for a long time ( rhabdomyolysis )
• Muscular dystrophy
• Myositis (skeletal muscle inflammation)
• Receiving many intramuscular injections
• Recent nerve and muscle function testing (electromyography)
• Recent seizures
• Recent surgery
• Strenuous exercise

Considerations

Factors that can affect test results include cardiac catheterization , intramuscular injections, recent surgery, and vigorous and prolonged exercise or immobilization.

Isoenzyme testing for specific conditions is about 90% accurate.

Creatine phosphokinase test

CPK test

Creatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle. This article discusses the test to measure the amount of CPK in the blood.

How the Test is Performed

A blood sample is needed. This may be taken from a vein. The procedure is called a venipuncture .

This test may be repeated over 2 or 3 days if you are a patient in the hospital.

How to Prepare for the Test

No special preparation is needed most of the time.

Tell your health care provider about any medicines you are taking. Drugs that can increase CPK measurements include amphotericin B, certain anesthetics, statins, fibrates, dexamethasone, alcohol, and cocaine.

How the Test will Feel

You may feel slight pain when the needle is inserted to draw blood. Some people feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

When the total CPK level is very high, it most often means there has been injury or stress to muscle tissue, the heart, or the brain.

Muscle tissue injury is most likely. When a muscle is damaged, CPK leaks into the bloodstream. Finding which specific form of CPK is high helps determine which tissue has been damaged.

This test may be used to:

• Diagnose heart attack
• Evaluate cause of chest pain
• Determine if or how badly a muscle is damaged
• Detect dermatomyositis , polymyositis , and other muscle diseases
• Tell the difference between malignant hyperthermia and postoperative infection

The pattern and timing of a rise or fall in CPK levels can be significant in making a diagnosis. This is particularly true if a heart attack is suspected.

In most cases other tests are used instead of or with this test to diagnose a heart attack.

Normal Results

Total CPK normal values:

• 10 to 120 micrograms per liter (mcg/L)

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

What Abnormal Results Mean

High CPK levels may be seen in people who have:

• Brain injury or stroke
• Convulsions
• Delirium tremens
• Dermatomyositis or polymyositis
• Electric shock
• Heart attack
• Inflammation of the heart muscle (myocarditis)
• Lung tissue death (pulmonary infarction)
• Muscular dystrophies
• Myopathy
• Rhabdomyolysis

Other conditions that may give positive test results include:

• Hypothyroidism
• Hyperthyroidism
• Pericarditis following a heart attack

Risks

Risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Considerations

Other tests should be done to find the exact location of muscle damage.

Factors that may affect test results include cardiac catheterization , intramuscular injections, trauma to muscles, recent surgery, and heavy exercise.

Creatinine blood test

Serum creatinine

The creatinine blood test measures the level of creatinine in the blood. This test is done to see how well your kidneys are working.

Creatinine can also be measured with a urine test.

How the Test is Performed

A blood sample is needed .

How to Prepare for the Test

The health care provider may tell you to temporarily stop taking certain medicines that can affect the test. These medicines include:

• Cimetidine, famotidine, and ranitidine
• Certain antibiotics, such as trimethoprim

Tell your provider about all the medicines you take.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or slight bruising. This soon goes away.

Why the Test is Performed

Creatinine is a chemical waste product of creatine. Creatine is a chemical made by the body and is used to supply energy mainly to muscles.

This test is done to see how well your kidneys work. Creatinine is removed from the body entirely by the kidneys. If kidney function is not normal, the creatinine level in your blood will increase. This is because less creatinine is released through your urine.

Normal Results

A normal result is 0.7 to 1.3 mg/dL for men and 0.6 to 1.1 mg/dL for women.

Women usually have a lower creatinine level than men. This is because women usually have less muscle mass than men. Creatinine level varies based on a person’s size and muscle mass.

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

A higher than normal level may be due to:

• Blocked urinary tract
• Kidney problems, such as kidney damage or failure, infection, or reduced blood flow
• Loss of body fluid (dehydration)
• Muscle problems, such as breakdown of muscle fibers ( rhabdomyolysis )
• Problems during pregnancy, such as seizures caused by eclampsia or high blood pressure caused by preeclampsia

A lower than normal level may be due to:

• Conditions involving the muscles and nerves that lead to decreased muscle mass
• Malnutrition

There are many other conditions for which the test may be ordered, such as high blood pressure, diabetes, or medicine overdose. Your provider will tell you more, if needed.

Risks

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and 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:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Creatinine clearance test

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

How the Test is Performed

This test requires both a urine sample and blood sample . You will collect your urine for 24 hours and then have blood taken. Follow instructions exactly. This ensures accurate results.

How to Prepare for the Test

Your health care provider may ask you to temporarily stop any medicines that may affect the test results. These include antibiotics and 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.

How the Test will Feel

The urine test involves only normal urination. There is no discomfort.

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. This soon goes away.

Why the Test is Performed

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

By comparing the creatinine level in urine with the creatinine level in blood , this test estimates the glomerular filtration rate (GFR) . GFR is a measure of how well the kidneys are working, especially the kidneys’ filtering units. These filtering units are called glomeruli.

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

Normal Results

Clearance is often measured as milliliters per minute (mL/min) or milliliters per second (mL/s). Normal values are:

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

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor 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
• Kidney failure
• Too little blood flow to the kidneys
• Damage to the filtering units of the kidneys
• Loss of body fluids (dehydration)
• Bladder outlet obstruction
• Heart failure

Risks

Risks of the test involve the blood draw process.

Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Creatinine urine test

Urine creatinine test

The creatinine urine test measures the amount of creatinine in urine. This test is done to see how well your kidneys are working.

Creatinine can also be measured by a blood test.

How the Test is Performed

After you provide a urine sample, it is tested in the lab. If needed, your doctor may ask you to collect your urine at home over 24 hours . Your health care provider will tell you how to do this. Follow instructions exactly so that the results are accurate.

How to Prepare for the Test

Your health care provider may tell you to temporarily stop taking certain medicines that may affect test results. Be sure to tell your provider about all the medicines you take. These include:

• Antibiotics such as cefoxitin or trimethoprim
• Cimetidine

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

How the Test will Feel

The test involves only normal urination. There is no discomfort.

Why the Test is Performed

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

This test is done to see how well your kidneys work. Creatinine is removed by the body entirely by the kidneys. If kidney function is not normal, creatinine level in your urine decreases.

This test can be used for the following:

• To evaluate how well the kidneys are working
• As part of the creatinine clearance test
• To provide information on other chemicals in the urine, such as albumin or protein

Normal Results

Urine creatinine (24-hour sample) values can range from 500 to 2000 mg/day. Results depend on your age and amount of lean body mass.

Another way of expressing the normal range for test results is:

• 14 to 26 mg per kg of body mass per day for men
• 11 to 20 mg per kg of body mass per day for women

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

What Abnormal Results Mean

Abnormal results of urine creatinine may be due to any of the following:

• High meat diet
• Kidney problems, such as damage to the tubule cells
• Kidney failure
• Too little blood flow to the kidneys, damage to filtering units
• Kidney infection (pyelonephritis)
• Muscle breakdown ( rhabdomyolysis ), or loss of muscle tissue ( myasthenia gravis )
• Urinary tract obstruction

Risks

There are no risks with this test.