laboratory tests

Albumin
To screen for a liver disorder or kidney disease or to evaluate nutritional status, especially in hospitalized . Albumin is the most abundant protein in the blood plasma. It keeps fluid from leaking out of blood vessels; nourishes tissues; and transports hormones, vitamins, drugs, and ions like calcium throughout the body. Albumin is made in the liver and is extremely sensitive to liver damage. The concentration of albumin drops when the liver is damaged, with kidney disease (nephrotic syndrome), when a person is malnourished, if a person experiences inflammation in the body, or with shock. Albumin increases when a person is dehydrated.


Total Protein and A/G Ratio
To determine your nutritional status or to screen for certain liver and kidney disorders as well as other diseases
A total serum protein test measures the total amount of protein in the blood. Two major groups of proteins in the blood are albumin and globulin.
• Albumin is made mainly in the liver. It helps keep the blood from leaking out of blood vessels. Albumin also helps carry some medicines and other substances through the blood and is important for tissue growth and healing.
• Globulin is made up of different proteins called alpha, beta, and gamma types. Some globulins are made by the liver, while others are made by the immune system. Certain globulins bind with hemoglobin. Other globulins transport metals, such as iron, in the blood and help fight infection. Serum globulin can be separated into several subgroups by serum protein electrophoresis. For more information, see the medical test Serum Protein Electrophoresis.


Protein Electrophoresis
Protein electrophoresis is used to evaluate, diagnose, and monitor a variety of diseases and conditions. It can be used for these purposes because the levels of different blood proteins rise or fall in response to such disorders as cancer (multiple myeloma), intestinal or kidney protein-wasting syndromes, disorders of the immune system, liver dysfunction, impaired nutrition, and chronic fluid-retaining conditions.


Aspartate aminotransferase
An AST test is ordered along with several other tests to evaluate a patient who seems to have symptoms of a liver disorder. Some of these symptoms include jaundice (yellowing of the eyes and skin), dark urine, nausea, vomiting, abdominal swelling, unusual weight gain, and abdominal pain. AST can also be ordered, either by itself or with other tests, for:
• persons who might have been exposed to hepatitis viruses,
• those who drink too much alcohol,
• persons who have a history of liver disease in their family, or
• persons taking drugs that can occasionally damage the liver.


Alanine aminotransferase
A physician usually orders an ALT test (and several others) to evaluate a patient who has symptoms of a liver disorder. Some of these symptoms include jaundice, dark urine, nausea, vomiting, abdominal swelling, unusual weight gain, and abdominal pain.


Gamma-glutamyl transferase
A doctor usually orders GGT along with other tests to evaluate a person who has signs or symptoms that suggest liver disease. Some of the symptoms of liver injury include jaundice, nausea, vomiting, abdominal swelling, abdominal pain, pruritus (severe itching), and fatigue.

Alkaline phosphatase
ALP is generally part of a routine lab testing profile, often with a group of other tests called a liver panel. It is also usually ordered along with several other tests if a patient seems to have symptoms of a liver or bone disorder.


5-nucleotidase
Serum 5'-N'Tase is measured as an indicator of liver damage resulting primarily from interference with the secretion of bile. Serum 5'-N'Tase is not as sensitive as some other enzymes (for example, ALP, AST, and ALT) to liver damage, but it is a more liver-specific enzyme. It is used mostly to differentiate elevated enzymes due to liver damage from elevated enzymes due to skeletal muscle damage.

Bilirubin
A doctor usually orders a bilirubin test in conjunction with other laboratory tests (alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase) for a patient who shows signs of abnormal liver function. A bilirubin level may be ordered when a patient shows evidence of jaundice (yellowing of eyes or skin), has a history of drinking excessive amounts of alcohol, suspected drug toxicity, or has been exposed to hepatitis viruses. Other symptoms that may be present include dark, amber-colored urine, nausea/vomiting, or abdominal pain and/or swelling. Fatigue and general malaise often accompany chronic liver disease. Determining a neonatal bilirubin level is considered standard medical care.

Alpha-1 Antitrypsin
To help diagnose the cause of early onset emphysema and/or liver dysfunction. To establish the risk of developing alpha-1 antitrypsin-related emphysema and/or liver disease and the likelihood that children might inherit the risk.


Ammonia
An ammonia test is done to:
• Check how well the liver is working, especially when symptoms of confusion, excessive sleepiness, coma, or hand tremor are present.
• Check the success of treatment for severe liver disease, such as cirrhosis.
• Help identify a childhood disorder called Reye's syndrome that can damage the liver and the brain. Ammonia testing can also help predict the outcome (prognosis) of a diagnosed case of Reye's syndrome.
• Help predict the outcome (prognosis) of a diagnosed case of acute liver failure.
• Check the level of ammonia in a person receiving high-calorie intravenous (IV) nutrition (hyperalimentation).


Urea
A blood urea nitrogen (BUN) test is done to:
• Determine whether your kidneys are functioning normally.
• Determine whether your kidney disease is getting worse.
• Monitor treatment of your kidney disease.
• Determine whether severe dehydration is present. A BUN-to-creatinine ratio may help your health professional determine whether decreased kidney function is the result of dehydration or kidney disease. Dehydration usually causes BUN levels to rise more than creatinine levels, resulting in an increased BUN-to-creatinine ratio. Kidney disease or blockage of the flow of urine from your kidney usually causes both BUN and creatinine levels to increase equally, resulting in a BUN-to-creatinine ratio that is normal.


Creatinine
A blood creatinine level or a creatinine clearance test is done to:
• Determine whether your kidneys are functioning normally.
• Monitor the progress of your kidney disease.
• Monitor the kidney function of people who take medications that can cause kidney damage.
• Determine whether severe dehydration is present. A BUN-to-creatinine ratio can help your health professional predict whether decreased kidney function is the result of dehydration or kidney disease. Dehydration usually causes BUN levels to rise more than creatinine levels, resulting in an increased BUN-to-creatinine ratio. Kidney disease or blockage of the flow of urine from the kidney usually causes both BUN and creatinine levels to increase to a similar degree, resulting in a BUN-to-creatinine ratio that is close to normal.


Uric Acid
A uric acid blood test is done to:
• Help diagnose gout.
• Check to see if kidney stones may be caused by high uric acid levels in the body.
• Check to see if medicine that increases or decreases uric acid levels is working.
• Check uric acid levels in people who are taking chemotherapy or radiation therapy.
Urine Total Protein
To detect excessive protein escaping into the urine, to help evaluate and monitor kidney function, and to detect kidney damage


Microalbumin
A microalbumin urine test is done to detect protein (albumin) in the urine, a condition called microalbuminuria, that means your kidneys have been damaged. Early detection may change treatment in an effort to preserve as much kidney function as possible.
It is recommended that Type 2 diabetics under the age of 70 and Type 1 diabetics over the age of 12 be screened annually for microalbuminuria. In addition, microalbumin may be ordered when a person is first diagnosed with Type 2 diabetes.


Kidney Stone Analysis
A kidney stone analysis is done to:
• Determine the chemical makeup of a kidney stone.
• Guide treatment for a kidney stone.
• Provide information on how to prevent future formation of a kidney stone.
Lactate dehydrogenase
To help identify the cause and location of tissue damage in the body, and to monitor its progress; historically, has been used to help diagnose and monitor a heart attack.


Creatine phosphokinase
To determine if you have had a heart attack or if other muscles in your body have been damaged

CK is ordered in patients who may have had a heart attack. The test will usually be ordered when a patient arrives at the emergency room and again at intervals of 4-6 hours for a total of three tests. If you have muscle pain or weakness, your doctor may also order CK to see if other muscles have been damaged.


Creatine Kinase–MB
To determine if you have had a heart attack and whether certain clot-dissolving drugs are working
CK-MB is usually ordered, along with total CK, in persons with chest pain to determine whether the pain is due to a heart attack. It may also be ordered in a person with a high CK to determine whether damage is to the heart or other muscles.


Troponin
To determine if you have had a heart attack or injury to heart muscle

Troponin tests are usually ordered, often along with other heart tests such as CK, CK–MB, or myoglobin, when a patient has prolonged chest pain or other symptoms that could be related to heart injury. Typically, troponin is done 2 or 3 times during a 12- to 16-hour period.


Myoglobin
To determine whether muscle, particularly heart muscle, has been injured

Because of the high confidence in the troponin test, many physicians do not order myoglobin. When it is ordered, it is ordered with troponin to assess persons with chest pain who are suspected of having a heart attack. Myoglobin levels are often used every 2-3 hours for the first several hours after a patient who has chest pain comes to the emergency room.



Amylase

A test for amylase is done to:
• Diagnose pancreatitis and other pancreatic diseases.
• Monitor the treatment of pancreatitis and other pancreatic diseases.
• Evaluate swelling and inflammation of the salivary glands.
• Determine if the intestines are damaged.
• Diagnose and monitor gallbladder attacks.


Lipase
A lipase test is done to:
• Diagnose pancreatitis and other diseases of the pancreas.
• Monitor the treatment of pancreatitis.
• Help diagnose or monitor cystic fibrosis.


Trypsinogen
To screen for cystic fibrosis (CF) and pancreatic insufficiency by evaluating pancreatic function
When you or your infant have symptoms of pancreatic insufficiency such as persistent diarrhea, foul-smelling bulky greasy stools, malnutrition, and vitamin deficiency; these are also symptoms of cystic fibrosis (CF), so trypsinogen may be ordered as part of newborn general population screening and/or if a newborn has meconium ileus (no stools in the first 24 to 48 hours of life)


Lipid Profile
The lipid profile is a group of tests that are often ordered together to determine risk of coronary heart disease. The tests that make up a lipid profile are tests that have been shown to be good indicators of whether someone is likely to have a heart attack or stroke caused by blockage of blood vessels (hardening of the arteries).
The lipid profile includes total cholesterol, HDL-cholesterol (often called good cholesterol), LDL-cholesterol (often called bad cholesterol), and triglycerides. Sometimes the report will include additional calculated values such as HDL/Cholesterol ratio or a risk score based on lipid profile results, age, sex, and other risk factors.


Cholesterol
Cholesterol and triglyceride testing is done:
• As part of a routine physical exam to screen for a lipid disorder.
• To check your response to medicines used to treat lipid disorders.
• To help determine your chances of having of heart disease, especially if you have other risk factors for heart disease or symptoms that suggest heart disease is present.
• If you have unusual symptoms, such as yellow fatty deposits in the skin (xanthomatosis), which may be caused by a rare genetic disease that causes very high cholesterol levels.


Triglyceride

Lipid profiles, including triglycerides, are recommended as routine tests to evaluate risk of heart disease in healthy adults. The test for triglycerides is not often ordered alone since risk of heart disease is based on cholesterol levels (see cholesterol, HDL, LDL), not triglycerides. However, if you have been found to have high triglycerides and are being treated for it, a triglyceride test may be ordered to see if treatment is working.


HDL Cholesterol
High-density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size (8-11 nm in diameter) and contents, that carry cholesterol from the body's tissues to the liver.Because HDL can remove cholesterol from atheroma within arteries, and transport it back to the liver for excretion or re-utilization, they are sometimes called "good cholesterol". When measuring cholesterol, any contained in HDL particles serves as protection to the body's cardiovascular health. (In contrast to "bad" LDL cholesterol.)


LDL Cholesterol
Low-density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying in their size (18-25 nm in diameter) and contents, which carry fatty acid molecules in the blood and around the body, for use by cells. It is the final stage of VLDL (very low-density lipoprotein) which is produced by the liver. The LDL contains the apolipoproteins B-100 and Apo E. It also contains antioxidative vitamins (vitamin E or carotinoids). It is commonly referred to as "bad cholesterol" due to the link between high LDL levels and cardiovascular disease.


Sodium
A test to measure sodium levels is done to:
• Evaluate the water balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body.
• Evaluate symptoms that may be caused by abnormal low or high levels of sodium.
• Monitor diseases of the kidneys or adrenal glands.

Potassium
A test to measure potassium is done to:
• Detect potassium levels in the blood that are too low (hypokalemia) or too high (hyperkalemia). This may be done for people being treated with medications (such as diuretics) that affect potassium levels and for people receiving kidney dialysis.
• Monitor the success of therapy to correct an abnormal high or low blood potassium level.
• Evaluate people with high blood pressure who may have a problem with their kidneys or adrenal glands.
• Monitor the effects of total parenteral nutrition (TPN) on blood potassium levels.
• Monitor certain cancer therapies that may cause cell lysis syndrome, a condition that occurs when cancer cells are rapidly destroyed. Cell lysis syndrome causes abnormally high blood levels of certain electrolytes, including potassium.


Calcium
A blood calcium test may be done:
• To evaluate suspected problems with the parathyroid glands or kidneys, certain types of cancers and bone diseases, inflammation of the pancreas (pancreatitis), kidney stones, and some abnormal results noted on an electrocardiogram (EKG) test.
• To investigate symptoms that may be caused by a very low calcium level in the blood. These symptoms may include muscle cramping and twitching, tingling in the fingers and around the mouth, spasms, confusion, or depression.
• To investigate symptoms that may be caused by a very high calcium level in the blood. These symptoms may include weakness, lack of energy, poor appetite, nausea and vomiting, constipation, frequent urination, or abdominal or bone pain.
• As part of a routine blood screening test.
Phosphorus
A test to measure phosphate in blood may be done to:
• Check phosphate levels if you have kidney disease or bone disease.
• Help find problems with certain glands, such as the parathyroid glands.
• Check phosphate levels if you have diabetic ketoacidosis.


Magnesium
A test for magnesium is done to:
• Determine a cause for nerve and muscle problems, such as muscle twitches, irritability, and muscle weakness.
• Determine the cause of a low calcium or potassium level that is not improving despite treatment.
• Screen for an excess of magnesium or for a magnesium deficiency (especially in people taking diuretics).
• Determine whether people with heart problems need additional magnesium. Low magnesium levels can increase the risk of potentially life-threatening heart rhythm problems.
• Measure levels when magnesium is being given for medical treatment.

Chloride
A test for chloride may be done to:
• Evaluate the electrolyte balance in your body. Too little chloride can cause muscle twitching, muscle spasms, or shallow breathing. Too much chloride can be associated with rapid deep breathing, weakness, confusion, and coma.
• Determine whether a problem with your kidneys or adrenal glands is present.
• Determine the cause for high blood pH. A condition called metabolic alkalosis can be caused by a loss of acid from your body (for example, from a loss of electrolytes through prolonged vomiting or diarrhea). Metabolic alkalosis can also result when your body loses too much sodium or from eating excessive amounts of baking soda (sodium bicarbonate).

Blood sugar
• Fasting blood sugar (FBS) measures blood glucose after you have not eaten for at least 8 hours. It often is the first test done to check for diabetes.
• 2-hour postprandial blood sugar (2-hour PC) measures blood glucose exactly 2 hours after you eat a meal.
• Random blood sugar (RBS) measures blood glucose regardless of when you last ate. Several random measurements may be taken throughout the day. Random testing is useful because glucose levels in healthy people do not vary widely throughout the day. Blood glucose levels that vary widely may indicate a problem. This test is also called a casual blood glucose test.


Blood glucose tests are done to:
• Check for diabetes.
• Monitor treatment of diabetes.
• Check for diabetes that occurs during pregnancy (gestational diabetes).
• Determine if an abnormally low blood sugar level (hypoglycemia) is present. A test to measure blood levels of a protein called C-peptide may be done along with a blood glucose test to determine the cause of hypoglycemia. For more information, see the medical test C-Peptide.


Oral Glucose Tolerance Test
The oral glucose tolerance test (OGTT) measures the body's ability to use a type of sugar, called glucose, that is the body's main source of energy. An OGTT is most commonly done to check for diabetes that occurs with pregnancy (gestational diabetes).
The oral glucose tolerance test (OGTT) is done to:
• Check pregnant women for gestational diabetes. When done for this purpose, the test is called a glucose challenge screening test, and it is usually done during the 24th to the 28th week of pregnancy. You have an increased chance of developing gestational diabetes if you:
o Have had gestational diabetes during a previous pregnancy.
o Have previously given birth to a baby who weighed more than 8.8 lb(4 kg).
o Are younger than age 25 and were overweight before getting pregnant.
• Confirm the presence of gestational diabetes if other blood glucose measurements are high.
• To screen women who have polycystic ovary syndrome (PCOS) for diabetes.


Glycated hemoglobin
Glycohemoglobin is a blood test that measures the amount of sugar (glucose) bound to hemoglobin. Normally, only a small percentage of hemoglobin in the blood (4% to 6%) has glucose bound to it. However, people with diabetes (or other conditions that increase their blood glucose levels) have more glycohemoglobin than normal.
Three types of glycohemoglobin—A1a, A1b, A1c—are measured in a total glycohemoglobin test. Test results help monitor the long-term control of blood glucose levels in people with diabetes.
This test is done to monitor treatment for diabetes. It may occasionally be used to help diagnose diabetes.


Fructosamine
Also known as: Glycated Serum Protein (GSP), Glycated Albumin
it is ordered If you are diabetic and your doctor wants to measure your average blood glucose level over the last 2-3 weeks
Although not widely used, the fructosamine test may be ordered whenever the doctor wants to monitor a patient's average glucose over the past 2 to 3 weeks. It is primarily ordered when a diabetic treatment plan is being instituted or altered in order to monitor the effect of the change in diet or medication. Fructosamine levels also may be ordered when a diabetic patient is pregnant, or when they have an acute or systemic illness that may change their glucose and insulin requirements for a period of time. The fructosamine test may be used when monitoring is required and an A1C test cannot be reliably used.


C-peptide
A C-peptide test measures the level of this peptide (an inactive amino acid) that is released in the body in amounts equal to insulin. Insulin helps the body use and control the amount of sugar (glucose) in the blood. Insulin allows glucose to enter body cells, where it is used for energy. The level of C-peptide in the blood can indicate how much insulin is being produced by the pancreas. See an illustration of the pancreas.
A test to measure the amount of C-peptide in the blood is done to:
• Distinguish between type 1 diabetes and type 2 diabetes.
• Determine the cause of low blood sugar (hypoglycemia).
• Monitor recovery after the removal of an insulin-producing tumor of the pancreas (insulinoma).


Insulin
Insulin levels are most frequently ordered following an abnormal glucose test and/or when a patient has acute or chronic symptoms of hypoglycemia, such as sweating, palpitations, hunger, confusion, visual problems, and seizures (although these can be caused by other conditions).


Blood Gases
An arterial blood gas (ABG) test is done to:
• Evaluate severe breathing problems and lung diseases, such as asthma, cystic fibrosis, or chronic obstructive pulmonary disease. It may also be used to monitor treatment for problems that affect breathing.
• Evaluate your need for extra oxygen or help with breathing (mechanical ventilation).
• Qualify you for home oxygen use.
• Measure the acid-base level in heart or kidney failure, uncontrolled diabetes, sleep disorders, a drug overdose, or a severe infection.
• Detect exposure to carbon monoxide and other chemicals.


Prealbumin
A doctor orders a prealbumin test when signs of malnutrition or poor nutrition are present. Signs of malnutrition include extreme weight loss, stunted growth (in a child), weakened resistance to infection, or being unable to think clearly. Hair may become brittle or begin to fall out, the skin may be dry or yellowish, muscles may feel weak, and fainting spells may occur. In younger women, menstrual periods may stop.


Bence-Jones protein - quantitative
This test measures the presence of Bence-Jones proteins (free immunoglobulin light chains) in urine.
This test is performed to aid in the diagnosis of disorders that can cause protein in the urine (proteinuria).


Ceruloplasmin
Ceruloplasmin is a test that measures the amount of ceruloplasmin (a copper-containing protein) in blood serum.
This test may be performed when disorders of copper metabolism or storage are suspected. Ceruloplasmin is the major copper-containing protein in plasma.
Lactose tolerance test
This is a test that measures the ability of your intestines to digest lactose. It is used to diagnose a deficiency of intestinal lactase (the enzyme used to digest lactose).


Human chorionic gonadotropin
To confirm and monitor pregnancy or to diagnose trophoblastic disease or germ cell tumors
When to get tested?
As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or if a doctor thinks that your symptoms suggest ectopic pregnancy, a failing pregnancy, trophoblastic disease, or germ cell tumors

A qualitative urine or blood hCG test is ordered as early as 10 days after a missed menstrual period if a woman wishes to confirm whether or not she is pregnant (some methods can detect hCG even earlier, at one week after conception). In certain patients, several quantitative blood hCG tests over several days may be ordered to rule out an ectopic pregnancy or to monitor a woman after a miscarriage. A doctor will also order a quantitative hCG test when s/he suspects trophoblastic disease or the presence of germ cell tumors.


Cancer Antigen 15-3
To monitor the response to treatment of invasive breast cancer and to watch for recurrence of the disease

CA 15-3 may be ordered along with other tests, such as estrogen and progesterone receptors, Her2/neu, and BRCA-1 and BRCA-2 genetic testing, when advanced breast cancer is first diagnosed to help determine cancer characteristics and treatment options.

Cancer Antigen 19-9
To help differentiate between cancer of the pancreas and bile ducts and other conditions; to monitor response to pancreatic cancer treatment and to watch for recurrence
CA 19-9 may be ordered along with other tests, such as carcinoembryonic antigen (CEA), bilirubin, and/or a liver panel, when a patient has symptoms that may indicate pancreatic cancer, including abdominal pain, nausea, weight loss, and jaundice.
If CA 19-9 is initially elevated in pancreatic cancer, then it may be ordered several times during cancer treatment to monitor response and, on a regular basis following treatment, to help detect recurrence.


Cancer Antigen 125
The test for cancer antigen 125 (CA-125) is used to:
• Check if treatment for cancer is working. If the level of CA-125 is going down, it usually means that the treatment is working.
• Check if cancer has returned.
• Check if the ovary is the main site of cancer in a woman. If a cancer is found at another site (metastatic cancer), a higher-than-normal CA-125 test result may mean that ovarian cancer is the main site.
The CA-125 test is not recommended as a screening test for ovarian cancer at this time. However, the CA-125 test and ultrasound may be used to test women who have a high chance for ovarian cancer. This would be women who have a family history of ovarian cancer that is likely to be inherited.


Alpha-fetoprotein
The AFP test is done to:
• Screen the fetus of a pregnant woman for brain or spinal problems (called neural tube defects). Such defects occur in about 2 out of every 1,000 pregnancies. The risk of a neural tube defect in a fetus is not related to the mother's age. Most women whose babies have neural tube defects have no family history of similar problems. When used to screen for birth defects, this test should be done between the 15th and 22nd weeks of pregnancy.
• Screen the fetus of a pregnant woman for Down syndrome. A low AFP level can detect Down syndrome about 60% of the time. The chance of detecting Down syndrome increases to about 80% when results of the AFP test are considered along with the results from two other tests (estriol and human chorionic gonadotropin). When done together, these three tests are called the triple test.
• Diagnose and monitor the effectiveness of treatment for some cancers, especially cancer of the testicles, ovaries, or liver. However, up to half of the people with liver cancer do not have high AFP levels.
• Screen for liver cancer (called hepatoma) among people who have cirrhosis or chronic hepatitis B.


Carcinoembryonic Antigen
The carcinoembryonic antigen (CEA) test is used to:
• Determine how widespread cancer is for some types of the disease, especially colon cancer.
• Monitor the success of treatment for colon cancer.
o CEA levels may be measured both before and after surgery to evaluate both the success of the surgery and the person's chances of recovery.
o CEA levels may be measured during treatment with medicines to destroy cancer cells (chemotherapy). This provides information about how well the treatment is working.
• Determine whether cancer has returned after treatment.


Prostate Specific Antigen
The prostate-specific antigen (PSA) test is done to:
• Monitor prostate cancer and how it responds to treatment. If PSA levels increase, the cancer may be growing or spreading. PSA is usually not present in a man who has had his prostate gland removed. A PSA level that rises after prostate removal may mean the cancer has returned or has spread.
• Determine if cancer may be present when other tests, such as a digital rectal exam, are not normal. A PSA test does not diagnose cancer, but it can be used along with other tests to determine if cancer is present.
• Check men for prostate cancer. Experts disagree on the usefulness of PSA testing as a screening tool for prostate cancer. If a PSA test is used for screening, it is usually done for men older than age 50 or for those at high risk for prostate cancer, such as men with a family history of prostate cancer, or for African-American men who have a higher chance of developing cancer than other men. Since other common medical conditions, such as prostatitis, can cause high PSA levels, a prostate biopsy is needed to confirm a diagnosis of cancer.