Regular blood testing is one of the most important ways to keep track of your overall physical well-being.
Getting tested at routine intervals can allow you to see the way your body changes over time and empower you to make informed decisions about your health.
Your doctor will typically recommend that you get routine blood work at least once a year, around the same time as your yearly physical.
But this is the bare minimum. There are several major reasons you may want to get blood tests more often than that:
- You’re experiencing unusual, persistent symptoms. These could include anything from fatigue to abnormal weight gain to new pain.
- You want to optimize your health. Knowing levels of various blood components, such as HDL and LDL cholesterol, can allow you to tweak your diet or fitness plan to minimize unhealthy habits (that you may not even realize are unhealthy). This can also maximize the nutrients you put in your body and more.
- You want to reduce your risk of disease or complications. Regular blood tests can catch the warning signs of almost any disease early. Many heart, lung, and kidney conditions can be diagnosed using blood tests.
Talk to your doctor first if you want to get certain tests more often than once a year.
Some of the most common routine tests are:
- complete blood count (CBC)
- chemistry (basic metabolic) panel
- thyroid panel
- nutrient tests for levels of vital nutrients, such as iron or B vitamins
Some other tests that you may want include:
Everything you eat and drink contains vitamins, proteins, and other nutrients that can cause the related levels in your blood to temporarily spike or drop.
Fasting for 8–12 hours helps ensure that blood test results are free from these variables, making your test results as accurate as possible.
Some common tests that may require fasting include:
- cholesterol tests
- blood sugar tests
- liver function tests
- kidney function tests
- basic metabolic panel
- glucose tests
Results may take anywhere from a few hours to a few days to become available. Here’s an overview of how long some common tests may take:
- complete blood count (CBC): 24 hours
- basic metabolic panel: 24 hours
- complete metabolic panel: 24–72 hours
- lipid panel: 24 hours.
This can depend on the specific lab where you get tested or how many tests you get done at once. If you order multiple tests, you may not get the complete results until all of the tests are completed.
Sometimes a lab will only release results to your doctor, who reviews them and then releases them to you.
Your doctor typically orders blood tests for you during a physical, checkup, or an appointment intended for a specific condition.
Blood testing is usually partially or fully covered by insurance. Ordering tests through your medical provider ensures that you’re not paying too much. Your doctor can also advise you on how to choose testing facilities that are reliable, well-managed, or convenient for you.
It’s possible to order your own blood tests without a doctor or even health insurance, but it’s not recommended. You may end up paying the full cost by not going through an insurance plan, which can be expensive.
And some blood testing facilities may not give you accurate results. One infamous case of this is Theranos, a Palo Alto, California, biotechnology firm shut down in 2018 when an investigation uncovered lies and fraud around the accuracy of its private blood testing technology.
Let’s take a closer look at tests for adults to have done regularly.
1. Complete blood count
A routine complete blood count (CBC) test checks for levels of 10 different components of every major cell in your blood: white blood cells, red blood cells, and platelets. Important components measured by this test include red blood cell count, hemoglobin, and hematocrit.
Here’s the typical range of results:
|red blood cells||men: 4.32–5.72 million cells/mcL; women: 3.90–5.03 million cells/mcL|
|white blood cells||3,500 to 10,500 cells/mcL|
|platelets||150,000 to 450,000/mcL|
|hemoglobin||men: 13.5–17.5 grams/deciliter (g/dL); women: 12.0–15.5 g/dL|
|hematocrit||men: 38.8–50.0 percent; women: 34.9–44.5 percent|
Abnormal levels of these components may indicate:
- nutritional deficiencies, such as vitamin B-6 or B-12
- iron deficiency
- bone marrow issues
- tissue inflammation
- heart conditions
Based on your results, your doctor will order follow-up tests to confirm abnormal levels and a possible diagnosis.
2. Basic metabolic panel
A basic metabolic panel (BMP) checks for levels of certain compounds in the blood, such as:
- carbon dioxide
- blood urea nitrogen (BUN)
This test requires you to fast for at least eight hours before your blood is drawn.
Abnormal results may indicate kidney disease, diabetes, or hormone imbalances. Your doctor will perform follow-up tests to diagnose any of these conditions.
3. Complete metabolic panel
A complete metabolic panel (CMP) includes all the measurements of a BMP as well as additional proteins and substances related to liver function:
- total protein
- alkaline phosphatase (ALP)
- alanine aminotransferase (ALT)
- aspartate aminotransferase (AST)
The same conclusions can be drawn from a CMP as from a BMP for the same substances that a BMP covers. Other abnormal levels can also indicate underlying conditions, such as:
|High levels||Low levels|
|ALP||• bile duct blockage|
• gallbladder inflammation
• Paget’s disease
|• bone metabolism disorders|
• heart surgery
• mentzinc deficiency
• liver cancer
• liver damage
• heart conditions
|Bilirubin||• abnormal red blood cell destruction (hemolysis)|
• adverse medication reactions
• bile duct blockage
• Gilbert’s syndrome
|not a concern|
4. Lipid panel
This test checks levels of
- high-density lipoprotein (HDL), or “good” cholesterol
- low-density lipoprotein (LDL), or “bad” cholesterol
HDL is “good” because it removes harmful substances from your blood and helps the liver break them down into waste. LDL is “bad” because it can cause plaque to develop in your arteries, increasing your risk of heart disease.
You need to fast for at least 8 hours before this test.
Here are the ranges for each type:
|HDL||> 60 mg/dL||men: < 40 mg/dL; women: < 50 mg/dL|
|LDL||> 160 mg/dL||< 100 mg/dL|
Normal levels can also vary by age.
5. Thyroid panel
A thyroid panel, or thyroid function test, checks how well your thyroid is producing and reacting to certain hormones, such as:
- Triiodothyronine (T3). Along with T4, this regulates your heart rate and body temperature.
- T3 resin uptake (RU). This measures how well a hormone called thyroxin-binding globulin is binding.
- Thyroxine (T4). Along with T3, this regulates your metabolism and how you grow.
- Thyroid-stimulating hormone (TSH). This helps regulate the levels of hormones your thyroid releases.
Your thyroid, a tiny gland in your neck, helps regulate bodily functions like your mood, energy level, and overall metabolism.
Here are normal results:
- T3:100–200 nanograms per deciliter of blood (ng/dL)
- T3RU:depends on T3 levels (will be low if T3 levels are high, and vice versa)
- T4: 5.0–12.0 micrograms per deciliter (μg/dL)
- TSH:0.4–4.0 milli-international units per liter of blood (mIU/L)
6. Enzyme markers
Enzymes are proteins that help your body accomplish certain chemical processes, such as breaking down food and clotting blood. They’re used throughout your body for many vital functions. Abnormal enzyme levels can indicate many different conditions.
Common enzymes tested include:
- Creatine phosphokinase (CPK-1). This is found in your lungs and brain. High levels can indicate brain injuries or cancer.
- CPK-2 (CK-MB). These enzymes are found in your heart. They often increase in your blood after a heart attack or other heart injury.
- CPK-3. These enzymes are also found in your heart. They often result from muscle inflammation, injury, or intense exercise.
- Troponin. This is a heart enzyme that can leak into your blood and results from heart injury.
Here are the normal ranges for the enzyme listed above:
- CPK-1:about 200 units per liter (U/L)
- CPK-2:5–25 international units per liter (IU/L)
- CPK-3:about 200 U/L
- troponin:< 0.02 ng/mL
7. Sexually transmitted disease tests
Many sexually transmitted diseases (STDs) can be diagnosed using a blood sample. These tests are often combined with urine samples or swabs of infected tissue for more accurate diagnoses.
The following STDs can be diagnosed with blood tests:
Blood tests aren’t always accurate right after contracting an infection. For an HIV infection, for example, you may need to wait at least a month before a blood test can detect the virus.
8. Coagulation panel
Clotting is a crucial process that helps your stop bleeding after a cut or wound. But a clot in a vein or artery can be deadly, blocking blood flow to your brain, heart, or lungs and causing heart attack or strokes.
Coagulation test results vary based on your health and any underlying conditions that may affect clotting.
Results from this test can be used to diagnose:
9. DHEA-sulfate serum test
The dehydroepiandrosterone (DHEA) hormone comes from your adrenal glands. This test measures whether it’s too high or too low.
In men, DHEA helps develop traits like body hair growth, so low levels are considered abnormal. In women, high levels can cause typically male traits, like excess body hair, to develop, so low levels are normal.
Low levels in men are called DHEA deficiency, which can be caused by:
High levels in men or women can result from:
- cancer or tumor in adrenal glands
- early onset of puberty from congenital adrenal hyperplasia
- abnormal genital development
- polycystic ovary syndrome (in women)
10. C-reactive protein test
C-reactive protein (CRP) is made by your liver when tissues in your body are inflamed. High CRP levels indicate inflammation from a variety of causes, including:
- artery inflammation
- inflammatory bowel disease (IBD)
- heart disease
- rheumatoid arthritis
The higher the level in your results, the higher your risk of heart disease:
- < 1 mg/L: low risk
- 1–2.9 mg/L: intermediate risk
- > 3 mg/L: high risk
- > 10 mg/L: extremely high risk, and further testing should be done to diagnose high levels of inflammation in your body
These procedures are usually done at a laboratory or in a doctor’s office and take a few minutes.
To perform a blood test, a nurse or technician:
- Cleans the area on your arm where they’ll draw the blood from.
- Ties a rubber band to your upper arm to help make your veins more visible.
- Puts a needle attached to a tube gently into a vein to draw blood.
- Removes the needle from the skin and takes the rubber band off your arm when the collection is complete.
- Covers the drawing site with a bandage or clean cotton and medical tape.
The risks of routine blood tests are very low, but can include:
- slight pain or discomfort when the needle goes in
- fainting from blood loss
- vein puncture
Blood tests offer an important snapshot of your overall health. They’re also a good way to catch illness or disease early or see how well your body responds to treatments for various conditions.
Get routine blood tests done at least once a year. Talk to your doctor to learn if there are any other tests you may need to ensure your optimal health.