Complete Guide to Lab Tests

What Are Lab Tests For?

The purpose of lab testing is to make you and your doctor aware of any changes in your health so you can make improvements as needed to stay healthy.

Your doctor may perform or order a lab test to confirm a diagnosis based on your symptoms, or to rule out suspected health conditions. Lab tests can help your doctor monitor a disease, and check whether it is progressing or going away. Lab tests also help your doctor determine whether a treatment is working as expected, or whether a treatment needs to be modified or discontinued to accelerate your healing.

A lab test usually requires you to provide a sample of urine, blood, saliva, hair follicle, or another bodily tissue. These tests are typically used to check for abnormalities that can point to a specific health condition or change in your health that requires immediate attention and treatment. After your results come back, your doctor will help you interpret them and discuss your next steps, such as whether you need additional treatment or should make certain lifestyle changes to prevent future health problems.

Categories of Lab Tests

Generally, many types of lab tests are available depending on your health goals, or whether your school or employer requires you to undergo certain testing. Your doctor may order lab tests from common categories based on your personal health situation.

Women’s Health

Routine lab testing is performed by many doctors who provide women’s wellness exams and healthcare services. Pap smears, pregnancy tests, and osteoporosis screening are some of many women-specific lab tests. A number of lab tests are also available to check hormones and fertility in women, including the follicle-stimulating hormone (FSH) test and luteinizing hormone (LH) test.

STD

STD lab tests can determine whether you have a sexually transmitted disease. According to Medline, these tests are ideal for people who are sexually active with multiple sex partners, and for those who think they may have been exposed to an STD. Syphilis, chlamydia, gonorrhea, HIV, and herpes are some of the many STD tests available for males and females.

Back to School

Some public and private schools require children to undergo yearly lab tests to ensure they do not have diseases or conditions that may put other children at risk. Tuberculosis (TB) skin testing, COVID-19 testing, and urine and blood testing are examples of tests your children’s school may require before every new school year.

Travel

Some countries require visitors to undergo testing to prove they do not have diseases and illnesses that can infect local citizens. COVID-19 test, malaria test, and blood titer test are examples of lab tests you may be required to have before or upon entering another country.

Work / Employment

Many employers require new and prospective employees to undergo certain lab tests so they can determine whether certain employees may be a liability or pose a risk to others in the workplace. Drug and alcohol screening and TB tests are common lab tests your employer may request before starting work.

Popular Lab Tests Your Doctor May Order

Some lab tests are performed as part of routine screening and wellness visits, while others may be performed to help your doctor learn more about the root cause of your symptoms and health conditions.

Your doctor may order some of these common and popular lab tests, depending on your health needs. Medline offers examples of how these test results can help you doctor determine next steps:

• Blood test: A sample of your blood can reveal a lot about your organs, immune system, DNA, and overall health. Many types of lab tests require a small blood sample to determine whether you have certain diseases, infections, and clotting disorders. Blood tests can also measure the levels of certain hormones and substances in your blood to help doctors choose the best treatments. Most blood tests take a sample from your vein or can be performed as a quick finger prick test.
• Drug test: A drug test can reveal whether you have been using certain types of illicit and prescription drugs. Employers, sports organizations, courts, and addiction treatment centers may ask you to do a drug test. Many drug tests are performed as urine or blood tests, though hair, saliva, and sweat tests may also be used. Drug tests can check your body for traces of drug metabolites, including those for marijuana, opioids, steroids, and cocaine.
• DNA test: A DNA test can detect whether you have genetic changes or abnormalities that may be causing illness and disease. These tests usually require you to provide a small sample of bodily fluids or tissues including blood, hair, or skin. DNA testing can be performed on people of all ages, including newborns.
• A1C test: The A1C test determines your average blood sugar level over the last three months. It is mainly performed on people with diabetes to check how well they are managing their blood sugar. The test requires a sample of your blood taken by a finger prick, or from a vein in your arm using a needle.
• Basic metabolic panel (BMP): A BMP measures eight different substances in your blood. These substances are: glucose, calcium, blood urea nitrogen, creatinine, sodium, potassium, carbon dioxide, and chloride. This test is usually performed to check certain bodily processes including metabolism, kidney function, and electrolyte balance. This test requires a sample of your blood taken from a vein in your arm.
• Cholesterol test: A cholesterol test is used to evaluate your body’s cholesterol levels, including LDL, HDL, triglycerides, and total cholesterol. This test is usually performed as part of a routine exam, or if you have a chronic condition such as type 2 diabetes or high blood pressure. It requires a blood sample from a vein in your arm and is usually performed in the morning on an empty stomach.
• Allergy Testing: An allergy test can determine whether you are allergic to certain substances including bee venom, penicillin, and pollen. It is usually performed as a skin test. During the test, a doctor injects a small amount of the suspected allergen into your skin and monitors whether you have a reaction.
• Food allergy test: A food allergy test may be performed as a blood test or skin test, and checks to see whether you are allergic to certain foods including peanuts, shellfish, and milk. In some instances, you may be instructed to eat small amounts of the suspected allergen so your doctor can watch for an allergic reaction.
• Glucose test: Also known as a diabetes test, a glucose test measures glucose levels in your blood. It is most commonly used to diagnose and monitor diabetes. This test is performed as a blood test.
• Diagnostic test: A diagnostic test is any lab test that helps your doctor diagnose a disease or health condition. Examples of diagnostic tests include the blood glucose test, flu test, and HIV test.
• Urinalysis: A urinalysis is also known as a urine test. A urine test requires you to expel a small amount of urine into a sterile cup, which is then evaluated in a lab for its acidity level, odor, and appearance, and to check for bacteria and substances including ketones, bilirubin, and glucose. Urinalysis is often used for drug testing, STD testing, diabetes testing, and many other lab tests.
• Vitamin D test: A vitamin D test can determine whether you are deficient in this essential vitamin, and screen and monitor bone disorders. This test is performed as a blood test.
• Pulmonary function test: This test is used to evaluate your lung health and measure your breathing. It is commonly used to diagnose various lung diseases and determine why you may have shortness of breath. A pulmonary function test may require you to breathe into an instrument called a spirometer.
• COVID-19 test: A COVID test is used to determine whether you have a coronavirus called SARS-CoV-2. It is usually performed as a swab test or saliva test. Samples may be taken from your nose or throat.

Tests for Common Infections

Your doctor may request that you undergo one or more of the below tests to confirm or rule out common infections. According to Medline, these tests may include some of the following:

• Flu test: Also known as the rapid influenza antigen test or rapid influenza diagnostic test, this test determines whether you have the flu. It can be used as a swab test to remove a sample from your nose or throat, or as a nasal aspirate where the doctor removes a sample from your nose using a gentle suction.
• Strep test: Also known as a strep A test, this test determines whether your sore throat is being caused by strep A bacteria. The strep test is usually performed as a throat culture, where a swab is used to collect a sample from your throat.
• TB test: This test determines whether you have been infected with TB, even if you have an inactive form of the disease. It can be performed as a skin test or a blood test.
• RSV test: This test checks to see if you have the respiratory syncytial virus that causes an infection of the lungs, nose, and throat. It can be performed as a swab test or blood test, or as a nasal aspirate where a sample is taken from your nose using gentle suction.
• H. pylori test: This test is used to detect whether you have H. pylori bacteria in the digestive tract, and to determine whether treatment for an H. pylori infection is working. It can be performed as a blood test, breath test, or stool test.
• MRSA test: This test determines if you have a type of staph bacteria called methicillin-resistant Staphylococcus aureus (MRSA). It can be performed as a blood test, urine test, or nasal swab test, or can take a sample of tissue from a wound you think is infected by MRSA.

Inflammatory/Autoimmune Tests

According to Medline, the following tests can help your doctor determine whether you have an autoimmune or inflammatory condition that requires ongoing treatment:

• Mono test: This test checks whether you have been infected with the mononucleosis virus, or the Epstein-Barr virus (EBV). A mono test uses a sample of blood to check for the virus, which can be taken from your fingertip or a vein in your arm.
• Arthritis test: Also known as a rheumatoid factor (RF) test, this test determines whether you may have rheumatoid arthritis by measuring the amount of RF in your blood. RFs are proteins made by the immune system. This test uses a sample of blood taken from a vein in your arm.
• ANA test: An antinuclear antibodies (ANA) test looks for antibodies in the blood to determine whether you have an autoimmune condition such as lupus, scleroderma, or Sjogren's syndrome. An ANA test is performed as a blood test.

Sexual/Reproductive Tests

According to Medline, the following tests can help determine whether you have been infected with an STD:

• HIV test: This test determines whether you have been infected with human immunodeficiency virus (HIV). It is usually performed as a blood test, but may also be performed as a saliva test.
• STD testing: STD testing can determine whether you have an STD including chlamydia, gonorrhea, genital herpes, HIV, and human papillomavirus (HPV). These infections can often be diagnosed using urine tests, blood tests, and swab tests, the latter of which takes a sample from your genitals.
• Trichomonas test: This test determines whether you have trichomonas, which is an STD caused by a parasite. It is performed using a swab sample from the genitals, and may also require a urine sample.

Hormone Tests

Hormone tests can often help detect hormone imbalances and problems that may interfere with your fertility. According to Medline, these tests include the following:

• Thyroid test: Also known as a thyroid-stimulating hormone (TSH) test, this blood test measures the amount of thyroid hormone you have to determine how well your thyroid is working. During this test, a doctor takes a sample of blood from a vein in your arm.
• FSH test: The FSH test measures the level of this hormone in your blood to detect problems with fertility and ovarian function, and to confirm the start of menopause in women. This test can also be performed in men and children to detect reasons for infertility and causes of delayed or early puberty. This blood test uses a sample of blood taken from a vein in the arm.
• LH test: The LH levels test measures the level of this hormone in your blood to determine the cause of infertility and the reason for irregular menstrual periods. It may also be used to determine the cause of early or delayed puberty in children. This test requires a doctor to draw blood from a vein in your arm.