Home/ Blog/ Live Well/

Your Guide to Lab Tests

Jun 22, 2020 By One Medical
Marketing

Updated September 1, 2020.

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.

Coronavirus Tests

COVID-19 Viral PCR Test

This test detects the presence of genetic material from the SARS-CoV-2 virus itself, and is the best test to diagnose an active case of COVID-19. It may sometimes be reported as “SARS-CoV-2, NAA.”

“Detected” result means SARS-CoV-2 genetic material was present.

If you have had symptoms, we recommend you continue self-isolation and stay home until the following three things have happened:

  • You have had no fever (temperature stays less than 100.4 F) for at least 24 hours without the use of fever-reducing medication

AND

  • Other symptoms have improved (for example, cough or shortness of breath have improved)

AND

  • At least 10 days have passed since your symptoms first appeared

Also, please reach out to your medical provider immediately if you experience severe symptoms, including:

  • Worrisome shortness of breath
  • Mental confusion
  • Chest pain or pressure that persists (not just with coughing)
  • Palpitations or irregular heartbeat
  • Fainting or almost fainting

We encourage you to check with your local department of health before discontinuing isolation to make sure our guidance aligns with your local regulations.

If you have not had symptoms, we recommend you:

  • Continue self-isolation and stay home for 10 days from the day you were tested
  • Wear a mask in public and stay 6 feet away from people for the following 3 days after isolation ends
  • If you develop symptoms within that time, isolate using the symptomatic instructions above

"Not Detected" Result means no SARS-CoV-2 genetic material was detected.

While this result means you likely do not have COVID-19, we strongly recommend continuing to care for yourself and practicing social distancing and handwashing regardless, as this test can sometimes miss SARS-CoV-2, especially if you haven’t had symptoms, or if you had symptoms but they started more than 7 days before the date of your test.

If you haven’t had any symptoms but you had an exposure to someone who tested positive for COVID-19, we advise you to stay home for 14 days since your last exposure to COVID-19.. If you did not have an exposure to someone who tested positive for COVID-19, we recommend continuing to monitor your health and practice social distancing.

If you are or have been symptomatic, we recommend you continue self-isolation and stay home until the following three things have happened:

  • You have had no fever for at least 24 hours without the use of fever-reducing medication

AND

  • Other symptoms have improved (for example, when your cough or shortness of breath have improved)

AND

  • At least 10 days have passed since your symptoms first appeared

Note that false negatives can occur if you’re tested too early after exposure to the virus. PCR testing tends to be most accurate when performed 8 days after exposure or within the first few days of symptoms. If you initially test negative but have a high suspicion for COVID-19 (ie. given your symptoms or an exposure), you may consider retesting, especially if you will be around high-risk individuals.

We understand that keeping up with the seemingly endless coronavirus news can feel overwhelming, so we have created a library of COVID-19 reference materials that are updated daily with the latest on what you need to know and what precautions can be taken to stay healthy.

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.

If your test for COVID-19 antibodies is positive:

This result indicates that you’ve likely been infected with SARS-CoV-2 in the recent past, and produced an immune response to the virus. This doesn't mean you’re immune, however, and you should consider yourself vulnerable to infection should you be exposed again. You should continue taking all the standard precautions to avoid exposure and avoid exposing others.

If your test for COVID-19 IgG antibodies is negative:

This result indicates that no antibodies to the virus were detected. This can happen for a number of reasons, including:

  • You’ve never been exposed to the virus
  • You were exposed but your body didn’t mount a detectable immune response
  • You were tested too early after infection (less than 14 days after infection), before your body had a chance to produce antibodies
  • You were tested too late after infection (more than 6 weeks after infection), after antibody levels have declined below the limit of detection.
  • Your result is a “false negative.”

You should consider yourself vulnerable to infection, and you should continue to practice all the standard precautions to avoid exposure to the virus, including wearing a mask when outside the home, maintaining a safe physical distance from others, avoiding crowded indoor settings, and washing your hands frequently.

We understand that keeping up with the seemingly endless coronavirus news can feel overwhelming, so we have created a library of COVID-19 reference materials that are updated daily with the latest on what you need to know and what precautions you can take to stay healthy.

antibody test chart guide to lab tests.png

General Lab Tests

Amylase/lipase: These tests check enzymes related to pancreatic function.

Basic metabolic panel (BMP): This includes tests of kidney function, electrolytes, and blood glucose (sugar).

Blood Urea Nitrogen (BUN): This is a test of kidney function.

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.

Lipid (aka Cholesterol) Panel

"Cholesterol" refers to a class of fats, also known as lipids, that circulate through the blood. Cholesterol levels can affect your risk for developing cardiovascular 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, LDL, 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.).

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.

Please see our guides to understanding the meaning of your cholesterol results and foods that help improve cholesterol numbers for more great info.

Complete blood count (CBC): This lab checks for signs of infection or anemia, and looks at various components of blood (red cells, white cells, platelets, etc.) to detect blood-related abnormalities.

Complete metabolic panel (CMP): This includes tests of kidney function, electrolytes, blood glucose (sugar) and liver function

Creatinine (Cr) and eGFR: Creatinine and eGFR provide an estimate of how well your kidneys are functioning. Note: On your lab report, you may see separate eGFR normal ranges for Black and non-Black individuals. At One Medical, we use the non-Black eGFR range for all individuals, as we believe that this approach will more accurately assess the health of Black individuals and identify the signs of kidney disease earlier.

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: Ferritin is a molecule that your cells use to store iron. This test is commonly ordered to further evaluate anemias and abnormal iron levels.

Free thyroxine (Free T4): This test is used to evaluate thyroid function and is often checked if TSH results are abnormal as part of a thyroid panel.

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.

For non-diabetic individuals:

  • <5.7%: This is normal.
  • 5.7-6.4%: This range is associated with an increased risk of developing diabetes
  • >6.4%: This result suggests a diagnosis of diabetes and a repeated test is required to confirm this diagnosis.

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

Hepatic Function Panel: This test evaluates various liver function tests and enzyme levels. Abnormalities can suggest inflammation in the liver or other potential liver or biliary (gallbladder, etc.) related issues.

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

Iron (Iron and TIBC): This test measures iron levels and the ability of red blood cells to retain iron. It can be helpful in identifying an iron deficiency or too much iron. It may be ordered if your provider thinks you are anemic, as iron deficiency is one possible cause of anemia. 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.

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

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.

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.

Thyroid Stimulating Hormone (TSH): This test is used to evaluate thyroid function and is useful in diagnosing or managing thyroid disorders including hyperthyroidism or hypothyroidism.

Triiodothyronine (T3): This test is used to evaluate thyroid function and is often checked if TSH results are abnormal as part of a thyroid panel.

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: This urine test is used to evaluate kidney function and is routinely monitored for patients with high blood pressure or diabetes.

Vitamin B12: This test checks for blood levels of vitamin B12. Deficiency in this vitamin can cause a variety of symptoms and health problems and should be discussed with your provider.

25-(OH)-Vitamin D: This tests for levels of vitamin D, which is associated with calcium absorption and bone health.

Tests for Common Infections

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.

Inflammatory/Autoimmune tests

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.

Sexual and Reproductive Health Tests

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.

Hormone tests

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 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.

Here to keep you healthy. And informed.
Get 24/7 care over video chat from the comfort of home or wherever you go. Join today and experience primary care designed for real life, in-office and in-app.
Join Today
One Medical

The One Medical blog is published by One Medical, an innovative primary care practice with offices in Boston, Chicago, Los Angeles, New York, Phoenix, Portland, the San Francisco Bay Area, Seattle, and Washington, DC.

Any general advice posted on our blog, website, or app is for informational purposes only and is not intended to replace or substitute for any medical or other advice. The One Medical Group entities and 1Life Healthcare, Inc. make no representations or warranties and expressly disclaim any and all liability concerning any treatment, action by, or effect on any person following the general information offered or provided within or through the blog, website, or app. If you have specific concerns or a situation arises in which you require medical advice, you should consult with an appropriately trained and qualified medical services provider.