Laboratory & Diagnostic Tests Glossary

AM cortisol levels are measurements of the amount of cortisol in the blood in the morning, usually between 6:00 and 8:00 am. Cortisol is a hormone produced by the adrenal glands in response to stress, and it is involved in regulating a variety of bodily functions, including metabolism, immune response, and blood pressure.

AM cortisol levels can be used to diagnose conditions such as adrenal insufficiency or Cushing’s syndrome. In adrenal insufficiency, the adrenal glands do not produce enough cortisol, which can cause fatigue, weight loss, and other symptoms. In Cushing’s syndrome, the body produces too much cortisol, which can cause weight gain, high blood pressure, and other health problems.

AM cortisol levels are typically measured through a blood test, which involves drawing a sample of blood from a vein in the arm. The test is usually performed in the morning, when cortisol levels are at their highest.

A BUN blood test, also known as a blood urea nitrogen test, is a common laboratory test that measures the level of urea nitrogen in your blood. Urea nitrogen is a waste product that is produced by the liver when it breaks down protein, and it is eliminated from the body by the kidneys.

The BUN test is often used to evaluate kidney function. If the kidneys are functioning properly, they will remove the urea nitrogen from the blood and excrete it in the urine. If the kidneys are not functioning properly, the level of urea nitrogen in the blood will be higher than normal.

A BUN blood test is a simple and commonly used test that can be done in a doctor’s office or laboratory. It involves taking a sample of blood from a vein in your arm. You do not need to fast or make any special preparations for the test.

BUN levels can be affected by a variety of factors, including dehydration, high protein intake, and certain medications. Therefore, your doctor will interpret the results of your BUN test in the context of your overall health and medical history.

In addition to evaluating kidney function, a BUN blood test can also be used to diagnose and monitor certain medical conditions, such as liver disease, heart failure, and gastrointestinal bleeding.

A CBC (complete blood count) blood test is a common laboratory test that provides information about the components of blood. It is used to assess overall health and detect a wide range of disorders, such as anemia, infection, and leukemia.The CBC measures several components of blood, including:

1. Red blood cells (RBCs): These cells carry oxygen throughout the body. The CBC can measure the number and size of RBCs.
2. White blood cells (WBCs): These cells help fight infection and disease. The CBC can measure the total number of WBCs and the different types of WBCs present.
3. Hemoglobin: This protein is found in red blood cells and helps carry oxygen throughout the body. The CBC can measure the amount of hemoglobin present.
4. Hematocrit: This measures the percentage of red blood cells in the blood.
5. Platelets: These cells help the blood clot. The CBC can measure the number and size of platelets.

A CBC blood test can help diagnose a variety of medical conditions and is often used as part of a routine health checkup.

A creatinine test is a blood test that measures the level of creatinine in your blood. Creatinine is a waste product that is produced by the muscles and is removed from the body by the kidneys. The creatinine level in the blood is a reflection of the kidney’s ability to filter waste products from the blood.

The creatinine test is often used to evaluate kidney function. If the creatinine level in the blood is high, it can be a sign of kidney dysfunction or damage. Other conditions that can cause elevated creatinine levels include dehydration, high blood pressure, and certain medications.

A creatinine test is a simple and commonly used test that can be done in a doctor’s office or laboratory. It involves taking a sample of blood from a vein in your arm. You may be asked to fast for a period of time before the test, and you may be asked to avoid certain medications that can affect the results of the test.

The normal range for creatinine levels in the blood can vary based on factors such as age, gender, and muscle mass. Your doctor will interpret the results of your creatinine test in the context of your overall health and medical history. Depending on the results, further testing or treatment may be recommended.

eGFR stands for estimated glomerular filtration rate. It is a measure of how well the kidneys are functioning to filter waste and excess fluids from the blood. The eGFR is calculated using a formula that takes into account the person’s age, sex, race, and blood creatinine level.

The eGFR is an important measure for assessing kidney function and is used to diagnose and monitor kidney disease. It is reported in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73m2). The normal eGFR range is generally considered to be greater than 90 mL/min/1.73m2, although this may vary depending on the person’s age and other factors.

If the eGFR is less than 60 mL/min/1.73m2 for three months or longer, it is an indication of chronic kidney disease. A lower eGFR may indicate that the kidneys are not functioning properly and may require further evaluation and treatment.

An electrolyte test is a blood test that measures the levels of various electrolytes in your blood. Electrolytes are minerals that have an electric charge and are important for a variety of functions in the body, such as regulating the balance of fluids in the body, transmitting nerve impulses, and contracting muscles.

The electrolyte test typically includes measurements of sodium, potassium, chloride, bicarbonate, calcium, and magnesium levels in the blood. These electrolytes are important for maintaining proper bodily function, and imbalances in their levels can be indicative of underlying health issues.

The electrolyte test is commonly used to evaluate kidney function and to diagnose and monitor certain medical conditions, such as dehydration, heart failure, liver disease, and electrolyte imbalances. It is also used to monitor the effects of certain medications, such as diuretics and blood pressure medications.

Your doctor will interpret the results of your extended electrolyte test in the context of your overall health and medical history. Depending on the results, further testing or treatment may be recommended.

For example, if you have low levels of potassium, your doctor may recommend dietary changes or potassium supplements. If you have high levels of calcium, your doctor may recommend further testing to investigate possible underlying medical conditions, such as hyperparathyroidism.

A lipid profile test is a blood test that measures the levels of different types of fats, or lipids, in your blood. This test is used to evaluate your risk of developing cardiovascular disease, which is caused by the buildup of fatty deposits in the walls of your arteries.A typical lipid profile test measures the following types of lipids:

1. Total cholesterol – this is the sum of all the cholesterol in your blood, including both “good” (HDL) and “bad” (LDL) cholesterol.
2. LDL cholesterol – this is the “bad” cholesterol that can build up in your arteries and increase your risk of heart disease.
3. HDL cholesterol – this is the “good” cholesterol that helps remove excess cholesterol from your blood and lower your risk of heart disease.
4. Triglycerides – these are another type of fat that can increase your risk of heart disease if your levels are too high.

Your healthcare provider may recommend a lipid profile test if you have risk factors for heart disease, such as high blood pressure, diabetes, or a family history of heart disease. They may also recommend regular lipid profile tests if you have already been diagnosed with heart disease or if you are taking cholesterol-lowering medications.

Your healthcare provider will use the results of your lipid profile test, along with other factors such as your age, sex, and smoking status, to assess your risk of developing heart disease and make recommendations for lifestyle changes or medications if necessary.

Liver enzymes are proteins produced by the liver that play a vital role in various bodily functions, including digestion, metabolism, and blood clotting. There are several different types of liver enzymes that can be measured through a blood test, including:

1. Alanine aminotransferase (ALT) – This enzyme is found primarily in the liver and is used to diagnose liver disease. Elevated levels of ALT may indicate liver damage, inflammation, or disease.
2. Aspartate aminotransferase (AST) – This enzyme is also found in the liver as well as in other organs such as the heart and muscles. Elevated levels of AST may indicate liver damage, but can also indicate damage to other organs.
3. Alkaline phosphatase (ALP) – This enzyme is found in many tissues in the body, including the liver and bones. Elevated levels of ALP may indicate liver disease or bone disorders.
4. Gamma-glutamyl transferase (GGT) – This enzyme is found in the liver and other tissues, and elevated levels of GGT may indicate liver damage, alcohol abuse, or other conditions.

If your liver enzyme levels are found to be elevated, further testing may be needed to determine the cause of the liver damage or disease. Treatment may include lifestyle changes, medications, or other interventions to address the underlying condition and prevent further liver damage.

Serum fasting insulin is a blood test that measures the level of insulin in the blood after a period of fasting. Insulin is a hormone produced by the pancreas that helps to regulate blood sugar levels in the body.

Fasting insulin levels are used to assess insulin resistance, a condition in which the body’s cells become resistant to the effects of insulin, leading to high blood sugar levels. Insulin resistance is a common precursor to type 2 diabetes, and can also be associated with other conditions such as metabolic syndrome, polycystic ovary syndrome (PCOS), and nonalcoholic fatty liver disease.

Treatment may include lifestyle changes such as exercise and a healthy diet, as well as medications to help regulate blood sugar levels and improve insulin sensitivity.

Serum FSH (follicle-stimulating hormone), LH (luteinizing hormone), and prolactin tests are blood tests that measure the levels of these hormones in the blood. These hormones play important roles in reproductive function.

1. FSH – In women, FSH helps to regulate the menstrual cycle and stimulate the growth and development of follicles in the ovaries. In men, FSH helps to stimulate the production of sperm. Abnormal FSH levels can indicate problems with fertility or menopause.
2. LH – In women, LH helps to trigger ovulation and the production of progesterone. In men, LH helps to stimulate the production of testosterone. Abnormal LH levels can indicate problems with fertility or menopause.
3. Prolactin – Prolactin is a hormone that is produced by the pituitary gland and plays a role in breast milk production. Elevated prolactin levels can indicate a prolactinoma, a benign tumor on the pituitary gland, which can affect fertility and menstrual cycles.

These tests may also be ordered if you have certain medical conditions that affect hormone levels, such as polycystic ovary syndrome (PCOS) or pituitary gland disorders.

Based on the results of these tests, your healthcare provider can diagnose hormone imbalances and develop a treatment plan tailored to your individual needs. Treatment may include medications, lifestyle changes, or other interventions to correct the hormone imbalances and improve your symptoms.

Serum sex hormone tests are blood tests that measure the levels of certain hormones in the blood that play a role in sexual development and reproductive function. These hormones include:

1. Testosterone – This hormone is primarily produced by the testicles in men and the ovaries in women, and plays a key role in male sexual development and reproductive function. In women, testosterone is produced in smaller amounts by the ovaries and adrenal glands and is involved in female sexual function. Free testosterone is often considered a more accurate measurement of the amount of testosterone available to the body, as bound testosterone is not available for use. Low levels of total or free testosterone can be associated with a range of health problems, including low sex drive, fatigue, depression, and decreased bone density.
2. Estrogen – This hormone is produced primarily by the ovaries in women and the testicles in men, and plays a key role in female sexual development and reproductive function. In men, estrogen is involved in bone health and other physiological functions.
3. Progesterone – This hormone is produced primarily by the ovaries in women and plays a key role in the menstrual cycle and pregnancy.

Your healthcare provider may order serum sex hormone tests if you are experiencing symptoms related to hormone imbalances, such as infertility, irregular periods, or low libido. These tests may also be ordered if you have certain medical conditions that affect hormone levels, such as polycystic ovary syndrome (PCOS) or low testosterone.

Based on the results of the serum sex hormone tests, your healthcare provider can diagnose hormone imbalances and develop a treatment plan tailored to your individual needs. Treatment may include lifestyle changes, medications, or hormone replacement therapy to correct the imbalance and improve your symptoms.

Thyroid blood tests are blood tests that measure the levels of certain hormones and proteins in your blood that are produced by the thyroid gland. The thyroid gland is a small, butterfly-shaped gland located in the neck that produces hormones that regulate many bodily functions, including metabolism, heart rate, and body temperature.

There are several different types of thyroid blood tests, including:

1. TSH (thyroid-stimulating hormone) test – This test measures the level of TSH in your blood, which is produced by the pituitary gland to stimulate the thyroid gland to produce thyroid hormones. High levels of TSH can indicate an underactive thyroid gland (hypothyroidism), while low levels can indicate an overactive thyroid gland (hyperthyroidism).
2. T4 (thyroxine) test – This test measures the level of T4, which is one of the primary hormones produced by the thyroid gland. Abnormal T4 levels can indicate an underactive or overactive thyroid gland.
3. T3 (triiodothyronine) test – This test measures the level of T3, which is another thyroid hormone that is produced in smaller amounts than T4. Abnormal T3 levels can indicate an underactive or overactive thyroid gland.
4. Thyroid antibody tests – These tests measure the level of antibodies that may attack the thyroid gland, causing autoimmune thyroid diseases such as Hashimoto’s thyroiditis or Graves’ disease.

If you have symptoms of thyroid disease, such as weight changes, fatigue, hair loss, or difficulty regulating body temperature. Thyroid blood tests may also be ordered if you have a family history of thyroid disease or if you are at risk of developing thyroid disease for other reasons. Based on the results of the thyroid blood tests, your healthcare provider can diagnose thyroid disorders and develop a treatment plan tailored to your individual needs.

Urate level, also known as uric acid level, refers to the amount of uric acid in the blood. Uric acid is a waste product that is produced by the breakdown of purines, which are substances found in many foods and in the body’s tissues. Uric acid is normally eliminated from the body through urine.

A urate level test is a blood test that measures the amount of uric acid in the blood. The test is often used to diagnose and monitor gout, a condition in which uric acid crystals accumulate in the joints, causing pain and inflammation. High levels of uric acid in the blood can also be a sign of other medical conditions, such as kidney disease or certain types of cancer.

Your doctor will interpret the results of your urate level test in the context of your overall health and medical history. Depending on the results, further testing or treatment may be recommended. For example, if you have high urate levels and a history of gout, your doctor may recommend lifestyle changes, medications, or other interventions to prevent gout attacks.

Urinalysis is a test that examines the physical and chemical properties of a urine sample. The test is used to help diagnose and monitor a range of conditions affecting the urinary system, such as urinary tract infections, kidney disease, and diabetes.

During a urinalysis, a healthcare provider will ask you to provide a urine sample in a sterile container. The sample will then be examined for the following:

1. Color and appearance – Urine should be clear and pale yellow in color. Cloudy or dark urine may indicate an infection or other health problem.
2. pH – The pH level of urine can help diagnose conditions such as kidney stones.
3. Specific gravity – This measures the concentration of particles in the urine and can indicate hydration levels and kidney function.
4. Glucose and protein – Elevated levels of glucose and protein in the urine can indicate diabetes or kidney disease.
5. Presence of bacteria or blood cells – This can indicate an infection or other health problem.

Based on the results of the urinalysis, your healthcare provider can make a diagnosis and develop a treatment plan tailored to your individual needs. Treatment may include medications, lifestyle changes, or other interventions to manage or cure the underlying condition.

A serum vitamin B12 level test is a blood test that measures the amount of vitamin B12 in your blood. Vitamin B12 is an essential nutrient that plays a key role in many important bodily functions, such as the production of red blood cells, the maintenance of healthy nerves, and the synthesis of DNA.

Low levels of vitamin B12 can lead to a variety of health problems, including anemia, nerve damage, and cognitive impairment. Some people are at higher risk of developing vitamin B12 deficiency, including older adults, vegetarians and vegans, and people with certain medical conditions that affect their ability to absorb B12.

A serum vitamin B12 level test may be ordered by your healthcare provider if you have symptoms of vitamin B12 deficiency, such as fatigue, weakness, numbness or tingling in the hands and feet, or difficulty thinking or remembering. It may also be ordered if you are at higher risk of developing vitamin B12 deficiency, such as if you are an older adult or a strict vegetarian.

If your vitamin B12 level is found to be low, your healthcare provider may recommend dietary changes or supplements to increase your intake of this essential nutrient. In some cases, injections of vitamin B12 may be needed to correct a deficiency. Your healthcare provider will work with you to determine the best course of treatment based on your individual needs and health status.

Vitamin D3, also known as cholecalciferol, is a type of vitamin D that is produced by the body in response to sunlight exposure. It can also be obtained through dietary sources such as fatty fish, egg yolks, and fortified foods and supplements.

Vitamin D3 plays an important role in the body’s absorption of calcium and phosphorus, which are essential for the development and maintenance of healthy bones and teeth. It also helps to support the immune system and regulate cell growth and differentiation.

A blood test can be used to measure the level of vitamin D3 in the body, which is typically reported as serum 25-hydroxyvitamin D [25(OH)D]. Low levels of vitamin D3 are associated with an increased risk of bone loss, osteoporosis, and fractures, as well as a range of other health problems such as cardiovascular disease, diabetes, and certain types of cancer.

Supplementation with vitamin D3 may be recommended if blood test results show a deficiency or insufficiency. Your healthcare provider can recommend the appropriate dose of vitamin D3 for your individual needs.

An abdominal ultrasound is a medical imaging test that uses high-frequency sound waves to produce images of the organs and structures within the abdomen. The test can help diagnose a variety of conditions, including liver disease, gallbladder disease, kidney stones, and abdominal tumors.

During an abdominal ultrasound, the patient lies down on an exam table and a gel is applied to the skin over the abdomen. A small handheld device called a transducer is then moved over the gel, emitting sound waves that bounce off the organs and structures in the abdomen. The sound waves are then converted into images that can be viewed on a screen.

The test is painless and non-invasive, and does not involve any exposure to ionizing radiation. The results of the test can be used to help diagnose medical conditions and guide treatment recommendations.

An audiogram is a test that measures a person’s ability to hear sounds of different frequencies and volumes. The test is commonly used to assess hearing loss and can help identify the type, degree, and configuration of hearing loss.

During an audiogram, the individual wears headphones and listens to a series of tones at different frequencies and volumes. They are then asked to indicate when they can hear the tones, which are played at increasingly lower volumes. The results of the test are recorded on an audiogram, which is a graph that shows the individual’s hearing ability at different frequencies and volumes.

Audiograms can be used to diagnose a variety of hearing conditions, including sensorineural hearing loss, conductive hearing loss, and mixed hearing loss. They can also be used to monitor hearing loss over time and to evaluate the effectiveness of hearing aids or other treatments.

An electrocardiogram (ECG or EKG) is a test that measures the electrical activity of the heart. It is a simple and non-invasive test that involves placing small electrodes on the chest, arms, and legs to record the electrical signals of the heart.

An ECG can be used to diagnose a variety of heart problems, including arrhythmias (abnormal heart rhythms), heart attacks, and heart failure. It can also be used to monitor the effects of medications or other treatments on the heart.

Overall, an ECG is a safe and useful test that can provide valuable information about the health of the heart.

An exercise stress test, also known as a treadmill test, is a medical test that evaluates the performance of the heart and lungs during physical activity. It is commonly used to diagnose and evaluate conditions such as coronary artery disease, heart failure, and arrhythmias.

During an exercise stress test, the patient walks on a treadmill or pedals a stationary bike while their heart rate, blood pressure, and breathing are monitored. The intensity of the exercise is gradually increased to raise the heart rate and simulate the demands of physical activity. The test may also include an electrocardiogram (ECG) to record the electrical activity of the heart.

Before the test, the patient is usually asked to avoid eating or drinking for a few hours, and to avoid caffeine and smoking for several hours prior to the test.

During the test, the healthcare provider will monitor the patient closely for signs of distress or discomfort. If the patient experiences chest pain, shortness of breath, dizziness, or other symptoms during the test, the test may be stopped.

An InBody test is a type of body composition analysis that provides a detailed analysis of an individual’s body composition. This test uses bioelectrical impedance analysis (BIA) to measure the distribution of body fat and muscle mass throughout the body.

During an InBody test, the individual stands on a specialized scale while holding two handles. The scale sends a low-level electrical current through the body, which is used to measure the resistance of different types of tissue in the body, such as fat and muscle. The test takes only a few minutes to complete, and provides a detailed report that includes information such as body fat percentage, muscle mass, water content, and basal metabolic rate.

InBody testing can be helpful for individuals who are interested in monitoring their body composition for health or fitness reasons. It can also be used by healthcare providers to help monitor patients with certain medical conditions, such as obesity or muscle wasting.

The results of an InBody test can be used to help guide dietary and exercise recommendations, and to monitor changes in body composition over time. However, it’s important to note that InBody testing may not be suitable for everyone, such as individuals with certain medical implants or conditions that can affect the accuracy of the test.

A male pelvic ultrasound is a medical imaging test that uses high-frequency sound waves to produce images of the organs and structures within the male pelvis, including the prostate gland, seminal vesicles, bladder, and surrounding tissue. The test can help diagnose a variety of conditions, including prostate cancer, benign prostatic hyperplasia (BPH), and urinary tract infections.

During a male pelvic ultrasound, the patient lies down on an exam table and a gel is applied to the skin over the pelvic area. A small handheld device called a transducer is then moved over the gel, emitting sound waves that bounce off the organs and structures in the pelvis. The sound waves are then converted into images that can be viewed on a screen.

The test is painless and non-invasive, and does not involve any exposure to ionizing radiation. The procedure typically takes about 30 minutes to complete.

A pelvic ultrasound is a medical imaging test that uses high-frequency sound waves to produce images of the organs and structures within the pelvis, including the uterus, ovaries, and bladder. The test can help diagnose a variety of conditions, including ovarian cysts, fibroids, and pelvic inflammatory disease.

During a pelvic ultrasound, the patient lies down on an exam table and a gel is applied to the skin over the pelvic area. A small handheld device called a transducer is then moved over the gel, emitting sound waves that bounce off the organs and structures in the pelvis. The sound waves are then converted into images that can be viewed on a screen.

The test is painless and non-invasive, and does not involve any exposure to ionizing radiation. Pelvic ultrasounds can be performed either transabdominally, with the transducer placed on the outside of the pelvis, or transvaginally, with the transducer inserted into the vagina.

A pulmonary function test (PFT) is a test that measures the function of the lungs. The test involves breathing into a machine called a spirometer, which measures the amount of air that the lungs can hold and how well the air is moving in and out of the lungs.

PFTs can be used to diagnose a variety of lung conditions, including asthma, chronic obstructive pulmonary disease (COPD), and interstitial lung disease. They can also be used to monitor lung function in people with these conditions or to assess lung function before surgery or other medical procedures.

During a PFT, the individual is asked to breathe in and out through a mouthpiece attached to the spirometer while sitting or standing. The test may include a series of breathing maneuvers, such as deep breathing, quick breathing, and forced exhalation. The results of the test are usually compared to predicted values based on the individual’s age, sex, height, and weight, and can help identify any abnormalities in lung function.

PFTs are generally safe and non-invasive, but some people may experience shortness of breath or lightheadedness during the test.

A visual acuity test is a test that measures how well a person can see. The test is typically performed using an eye chart, which contains rows of letters or symbols in various sizes. The person being tested is asked to stand a certain distance away from the chart and read the letters or symbols from top to bottom.

The results of the test are usually recorded as a fraction, with the first number representing the distance at which the chart was viewed, and the second number representing the smallest size of the letters or symbols that the person could read. For example, a result of 20/40 would mean that the person could read letters that were half the size of those read by someone with “normal” vision from a distance of 20 feet.

Visual acuity tests are commonly used to assess the sharpness of a person’s vision, and to diagnose conditions such as nearsightedness, farsightedness, and astigmatism. They can also be used to monitor the progression of certain eye conditions, and to evaluate the effectiveness of vision correction methods such as glasses or contact lenses.