Your guide to common lab tests

Clinical Editors: Spencer Blackman, MD, Zach Ortiz, MD, MPH

Originally published Feb 14, 2022.

We know that understanding your test results can be difficult, as lab reports are often filled with abbreviations, unfamiliar terms, and lots of numbers. We hope this guide will help you better understand what some of the most common laboratory tests are used for and what your results mean. Please reach out to your provider if you have questions about your specific result(s).

Looking for a specific test? You can use your browser’s search function to find the test(s) you are looking for.

Amylase/lipase

These tests check enzymes related to pancreatic function.

Apo B

ApoB, or apolipoprotein B, is a protein that plays a crucial role in transporting fats, or lipids, throughout the body. Think of it as a kind of "cargo tag" that helps package and deliver cholesterol and other fats to cells that need them for various functions.This tag also helps it deliver fats to artery walls, speeding up the process of atherosclerosis which can lead to heart attacks and strokes. Monitoring apoB levels can give insight into a person's risk for cardiovascular diseases, and levels can also be used to set goals of medical therapy.

Basic metabolic panel (BMP)

A BMP is a group of tests that measure your blood sugar (glucose), electrolyte and fluid balance, and your kidney function.

If one or more of the tests results in your BMP is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range, but stable for your health conditions. You can discuss this with your provider.

Blood urea nitrogen (BUN)

This is a test of kidney function.

Calcium

Calcium is a mineral in the body that is necessary for your body’s nerve, heart, and muscle function. Calcium is also important for bone maintenance and formation.

Celiac disease panel

This test may be ordered if there is concern that you have Celiac disease, an autoimmune disease that causes an immune response to gluten. Symptoms of Celiac disease may include diarrhea, bloating, abdominal pain, and anemia. If untreated, long term complications can result.

Complete blood count (CBC)

A CBC is a group of tests that evaluates cells that circulate in blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs). This panel of tests may be ordered to help diagnose or monitor infection, anemia, or other conditions affecting the blood.

If one or more of the tests results in your CBC is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. You can discuss this with your provider.

Complete metabolic panel (CMP)

A CMP is a group of tests that measure your blood sugar (glucose), electrolyte and fluid balance, and your kidney and liver function. This panel of tests may be ordered to check one’s overall health status; to help diagnose or evaluate the effects of certain conditions such as diabetes, liver disease, kidney disease, or high blood pressure; or to monitor the effects of certain medications.

If one or more of the tests results in your CMP is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. You can discuss this with your provider.

Creatinine (Cr) and eGFR

A creatinine test measures kidney function and detects, evaluates, and monitors kidney disease or damage.

eGFR also provides an estimate of how well your kidneys are functioning. If your creatinine result is outside of the normal range: High creatinine levels may be due to dehydration or decreased kidney function, while low levels are not usually a cause for concern. Elevated creatinine levels can also be caused by a diet very high in protein,by taking supplements that contain creatine or in people with higher muscle mass. Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. You can discuss this with your provider.

Fecal occult blood test (FOB)

In this test, your stool sample is examined for microscopic amounts of blood that may not be visible by simple visual examination. The presence of blood in stool typically warrants follow-up screening by colonoscopy for a cause (such as polyps or colon cancer), while the absence of blood would indicate no need for further testing. This test can be performed annually as an option for colon cancer screening.

Ferritin

Your cells use ferritin to store iron. A ferritin test is commonly ordered to further evaluate anemias and abnormal iron levels. It can be elevated with infection and in some conditions that cause inflammation in the body.

If your ferritin result is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. You can discuss this with your provider.

Glucose

This lab looks at your blood sugar level at the time of testing.

For non-diabetic individuals:

• < 100 mg/dL: This is normal.
• 100-199 mg/dL:
  • If you ate eight hours or less prior to your blood test, this range is normal.
  • If you hadn’t eaten for 8 hours or more you were fasting. Fasting blood sugar levels between 100 and126 mg/dL could mean you are at increased risk to develop diabetes.
  • If you were fasting and your result was 126 mg/dL or greater, you may have diabetes and a follow up test is required to confirm this diagnosis.
• 200 mg/dL or greater: Whether fasting or not, this range suggests the diagnosis of diabetes.

If you have diabetes, please review your result with your provider.

H. pylori breath test

This test looks for signs of H. pylori, a bacteria that can cause stomach and small intestinal ulcers.

Hemoglobin A1c

This is a measure of your average blood sugar level over the past three months. This test result isn’t affected by fasting.

If your A1c result is outside of the normal range:

• and you don’t have diabetes: You may already be monitoring this level with your provider. If you aren’t, know that an elevated result may require future follow-up testing and/or lifestyle modifications (read more here).
• and you have diabetes: Your provider will reach out if they recommend any changes to your diabetes care based on your A1c (read more here).

If you have diabetes, please review your result with your provider.

Hepatic function panel

A liver panel is a group of tests that are performed together to detect, evaluate, and monitor liver disease or damage.

If one or more of the tests results in your panel is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. Depending on your levels, your previous baseline, health habits and medical conditions, your provider may want to perform follow-up testing or continue to monitor this level at future visits. You can discuss this with your provider.

INR, Prothrombin time

These tests assess blood clotting abilities and are commonly checked for patients who take blood thinners (e.g., Coumadin).

Iron and TIBC

This test can be helpful in identifying iron levels that are too low (one possible cause of anemia) or too high.

If your iron result is outside of the normal range: Low levels may be due to some chronic diseases, low dietary intake of iron, gastrointestinal tract issues, or increased iron needs during times like pregnancy. High levels, on the other hand, may be due to frequent blood transfusions, lead poisoning, liver or kidney disease, or a genetic condition called hemochromatosis. Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions. You can discuss this with your provider.

Lipid (aka Cholesterol) panel

"Cholesterol" refers to a class of fats, also known as lipids, that circulate through the blood. Different types of cholesterol can increase or decrease your risk for developing heart disease.

Several types of cholesterol make up the lipid panel:

• Total cholesterol is a measurement of all of the types of cholesterol in your blood, including HDL cholesterol, LDL cholesterol, and triglycerides.
• Triglycerides are a type of fat that the body generates when excess calories are consumed, particularly calories from carbohydrates and fats. They are stored in fat cells and can circulate in the blood. High levels are associated with increased risk for developing heart disease and are often found together with elevated blood sugar. Diet, exercise, and family genetic background have a major impact on triglyceride levels. They can be lowered significantly with improved diet and exercise. (See the recommendations outlined below.)
• High density lipoprotein (HDL) is considered the "good" cholesterol because it helps the body clear "bad" cholesterol from your arteries and can help protect against heart disease (ie: heart attacks and strokes).
• Low density lipoprotein (LDL) is considered the "bad" cholesterol because over time it can line blood vessel walls leading to damage (“atherosclerosis”) and subsequent heart disease (heart attacks and strokes, e.g.).

If one or more of the tests results in your lipid panel is outside of the normal range:

Frequently, one or more components of the cholesterol panel are flagged as abnormal when they are, in fact, completely normal based on an individual patient’s risk factors for heart disease. Unless you’ve been told otherwise by your provider, rest assured a bolded result on your report is not necessarily concerning.

Magnesium

Magnesium is a mineral and, when deficient , can cause weakness, twitching, cramping, confusion, cardiac arrhythmias, and seizures.

Potassium

This tests for levels of potassium electrolytes in your bloodstream. It is commonly monitored in relation to kidney disease or treatment for high blood pressure.

Prostate specific antigen (PSA)

This is a blood test that can be used to aid in the diagnosis of prostate enlargement, prostate cancer, and other prostate-related conditions.

Serum HCG

This is a blood test that is commonly used to help confirm when someone is pregnant and can also help determine how far along in pregnancy someone is.

Uric acid

This test is commonly used to aid in the diagnosis or management of gout.

Urinalysis (UA)

This test evaluates a urine sample for signs of infection, blood, or other abnormalities.

Urine culture

This test looks for bacterial growth in urine. It can be helpful in determining if you have a urinary tract infection. If abnormal, sensitivity testing is typically performed to determine which antibiotics would be effective against the bacteria isolated in the urine sample.

Urine microalbumin/creatinine ratio

This test measures small amounts of a blood protein called albumin in your urine. It can help to identify early kidney disease and is often used to monitor kidney health in those with diabetes or high blood pressure.

If your urine microalbumin result is outside of the normal range: When your urinary microalbumin level is elevated, your provider may recommend treatments, modifying or stopping certain medications or repeat testing. You can discuss this with your provider.

Vitamin B12

This test detects low levels of vitamin B12 as a possible cause of symptoms, evaluates nutritional status, or monitors levels after vitamin supplementation.

If your Vitamin B12 result is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions.You can discuss this with your provider.

Vitamin D3

Vitamin D helps the body absorb calcium and supports bone health. This test may be ordered to monitor vitamin D levels when taking a supplement, to screen for deficiency due to symptoms, or to monitor conditions that affect vitamin D Levels.

If your Vitamin D result is outside of the normal range: Not all results flagged as out of the normal range are a cause for concern. Some may be out of range but are not important in the context of your overall health. Others may be out of range but stable for your health conditions.You can discuss this with your provider.

COVID-19 viral PCR test

Also known as NAA or NAAT, these tests detect the presence of genetic material from the SARS-CoV-2 virus itself, and are used to diagnose an active case of COVID-19. It may sometimes be reported as “SARS-CoV-2, NAA.”

COVID-19 viral antigen testing

These tests detect components of the SARS-CoV-2 virus that are present during an active infection.

COVID-19 IgG antibody testing

This test identifies a type of antibody present in your system and can indicate that you have mounted an immune response to SARS-CoV-2, the virus that causes COVID-19 (coronavirus) infection.

To learn more about COVID-19 testing, check out our complete guide to COVID-19 testing at One Medical.

Bacterial cultures

A culture seeks to grow infectious bacteria using a sample source from the body such as urine, blood, an open wound, stool, or other fluids. If positive, the result usually identifies the specific type of bacteria and may identify which antibiotics can be used to treat the infection.

Hep A Ab, total

Hepatitis A is a viral infection of the liver. This tests for the presence of hepatitis A antibodies. Elevated levels reflect immunity either through previous vaccination or exposure to the illness.

Hep B Ab, IgG

Hepatitis B is a viral infection of the liver. This tests for the presence of hepatitis B antibodies. Elevated levels reflect immunity either through previous vaccination or exposure to the illness.

Hep C Ab

Hepatitis C is a viral infection of the liver. This test checks for the presence of hepatitis C antibodies, which can be associated with active hepatitis C infection.

Lyme disease Ab

This is an antibody test that is used to aid in diagnosis of Lyme disease, a tick-borne illness.

Measles, Mumps, Rubella (MMR) immunity profile

This lab test indicates if you have immunity to measles, mumps, and rubella.

Mononucleosis

This tests for antibodies associated with mononucleosis (mono) and can aid in the diagnosis of acute or active infection.

Quantiferon gold (Tuberculosis)

This test is used to identify individuals with latent tuberculosis, meaning the infection is dormant without active symptoms or infectivity.

Strep

This test is performed to aid in diagnosis of strep throat. This throat swab is cultured for bacteria Streptococcus pyogenes, also known as group A streptococcus, the most common cause of bacterial infections of the throat.

Varicella Zoster Virus (VZV) antibodies, IgG

This test is useful in determining if you are immune to varicella zoster, the virus that causes chickenpox and shingles.

Antinuclear antibody panel (ANA)

This is a common initial test in the process of diagnosing a range of autoimmune conditions.

C-reactive protein (CRP)

This test assesses levels of an inflammatory marker that can be elevated in various situations, including infectious, autoimmune, and rheumatologic conditions.

Erythrocyte Sedimentation Rate (ESR)

This test assesses levels of an inflammatory marker that can be elevated in various situations, including infectious, autoimmune, and rheumatologic conditions.

Hs-CRP

This test assesses levels of an inflammatory marker that can be used in assessing one’s risk for developing heart disease.

Rheumatoid factor (RF)

This is a common initial test in the process of diagnosing a range of autoimmune conditions.

Chlamydia

This test is used to detect the presence of chlamydia, a sexually transmitted disease, in the urine, throat, rectum, urethra, or cervix. This is commonly tested in combination with gonorrhea, and the two are generally reported together (i.e. Ct/GC NAA).

Gonorrhea

This test is used to detect the presence of gonorrhea, a sexually transmitted disease, in the urine, throat, rectum, urethra, or cervix. This is commonly tested in combination with chlamydia, and the two are generally reported together (i.e. Ct/GC NAA).

HIV (HIV Screen 4th Generation wRfx)

This test is used to screen for the presence of HIV antibodies and an HIV specific antigen (molecular marker of HIV). A positive test automatically reflexes to additional confirmatory testing for diagnosis.

Rapid plasma reagin (RPR)

This test is used to screen for syphilis infection and monitor the effectiveness of syphilis treatment.

Vaginitis DNA probe

This test helps identify the cause of symptoms of vaginitis.

Check out our guide for more information on STD screening.

Follicle stimulating hormone (FSH)

This test looks at follicle stimulating hormone levels. In women, this hormone impacts the menstrual cycle and egg production, and varies depending on the timing of a woman’s menstrual cycle. Levels in males impact sperm production.

Luteinizing hormone (LH)

This test looks at levels of luteinizing hormone, a hormone that impacts ovulation in women and testosterone production in males.

Prolactin

This test looks at levels of prolactin, a hormone produced in the pituitary gland. This test can be used to evaluate possible issues with the pituitary gland and hypothalamus. It may be used to evaluate fertility, erectile dysfunction, abnormal hair growth, headaches, visual impairment, painful intercourse, or abnormal milk production outside of breastfeeding.

Testosterone

This test looks at testosterone levels, a sex hormone that is important for both men and women. This hormone impacts sex drive, reproductive health, fertility, and physical characteristics.

Thyroid tests

The thyroid is a gland responsible for making hormones that help regulate growth and energy. Thyroid tests are useful in detecting and treating thyroid disorders, such as hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid). A Thyroid Cascade or Thyroid Panel will run a range of thyroid tests (see below bullets for some of the most common thyroid tests in a panel).

• Thyroid Stimulating Hormone (TSH): A TSH test measures thyroid function and is useful in diagnosing or managing thyroid disorders.
• Triiodothyronine (T3), Triiodothyronine (T3) Free, Thyroxine (T4), and Thyroxine (T4) Free: All of these tests also measures thyroid function and often are interpreted with thyroid stimulating hormone (TSH) as part of a thyroid panel to evaluate for thyroid disorders.
• If one or more of the tests results in your panel is outside of the normal range: Starting or modifying thyroid medication or follow up blood work may be indicated based on your results. You can discuss this with your provider.

Have questions about getting your labs done at One Medical? Learn more about our on-site lab services. For questions about a specific test or lab results, please reach out to your primary care provider.