Most healthy adults need routine blood work once a year, typically as part of an annual physical exam. That baseline frequency changes based on your age, any chronic conditions you manage, and whether you take certain medications. Here’s a breakdown of what’s recommended and when.
Annual Blood Work for Healthy Adults
If you have no chronic health conditions and feel well, a yearly blood panel is the standard recommendation. This usually includes a complete blood count, a basic metabolic panel checking kidney function and blood sugar, and a liver function panel. Your doctor may add or subtract tests depending on your age and risk factors, but once a year is the general rhythm for people without ongoing health concerns.
Cholesterol Screening by Age
Cholesterol testing follows its own schedule, separate from your general annual labs. The American Heart Association recommends starting cholesterol screening at age 20, then repeating it every four to six years for adults with no known risk factors for heart disease. Young adults without lipid disorders can stretch to every five years starting at age 19, but the frequency should increase as you get older or if you develop risk factors like high blood pressure, smoking, or a family history of heart disease.
If you’re already taking a cholesterol-lowering medication, the timeline tightens. Guidelines call for a lipid panel four to 12 weeks after starting or changing treatment, then every six to 12 months. Once your levels are stable and your treatment plan isn’t changing, once a year is sufficient.
Blood Sugar and Diabetes Screening
The U.S. Preventive Services Task Force recommends screening for prediabetes and type 2 diabetes in adults aged 35 to 70 who are overweight or obese. If you’re overweight, repeat screening every three years up to age 70.
For people already diagnosed with diabetes, blood sugar monitoring through an A1C test (which reflects your average blood sugar over two to three months) happens more frequently. If you’re meeting your treatment goals and blood sugar targets, every six months is typical. If your treatment has recently changed or you’re struggling to reach your goals, that moves to every three months.
Thyroid Function Tests
If you take thyroid medication, expect blood work every six to eight weeks when you first start treatment or after any dose change. Once your levels normalize, annual testing is the standard. For people being treated for an overactive thyroid (Graves’ disease or other causes), your doctor will typically wait at least one month, often longer, before rechecking levels because the hormones involved can stay suppressed for extended periods after treatment begins.
Blood Thinners and Other Medications
Certain medications require their own blood monitoring schedules. If you take warfarin (a common blood thinner), you’ll need frequent testing of your blood’s clotting time. Early on, this can mean checks every few days until your levels stabilize, then every one to four weeks. For patients with stable levels, testing can extend to every 12 weeks. Elderly patients generally need checks at least every six weeks. Any time you add or stop another medication, switch brands, or leave the hospital, your doctor will likely increase monitoring temporarily.
Newer blood thinners like apixaban and rivaroxaban require less frequent monitoring: a baseline test, then yearly and whenever a clinical concern arises. Statins (cholesterol medications) need a baseline liver function test but don’t require routine liver monitoring afterward unless symptoms develop. Your doctor will check your cholesterol levels on the schedule described above to confirm the medication is working.
Vitamin D and Iron Levels
Despite the popularity of checking vitamin D, routine screening isn’t recommended for most people. Testing is reserved for those at high risk of deficiency: people with malabsorption conditions, kidney disease, unexplained bone pain, unusual fractures, or metabolic bone disorders. If you’re taking a standard vitamin D supplement, you don’t need blood work to monitor it. Ongoing monitoring after supplementation is only indicated for people with conditions like kidney disease or metabolic bone disease who are already seeing a specialist.
One-Time Screening Tests
A few blood tests are recommended just once in your lifetime. All adults aged 18 to 79 should get a one-time hepatitis C screening. HIV screening is recommended for everyone aged 15 to 65. Hepatitis B screening applies if you’re at increased risk of infection. These don’t repeat on a schedule unless you have ongoing risk factors.
Adults Over 65
After 65, screening schedules generally continue but may be adjusted. Cholesterol checks follow the same four-to-six-year cycle if you have no risk factors, though many older adults are already on cholesterol medication and follow the tighter monitoring schedule. Diabetes screening every three years remains relevant if you’re overweight. Prostate cancer screening through a PSA blood test is an option for men over 65, but the ideal frequency isn’t established, so it’s worth discussing whether the test makes sense for your situation.
Fasting Before Blood Tests
Some common blood tests require you to skip food for 8 to 12 hours beforehand. The most common fasting tests are blood glucose (blood sugar), cholesterol panels, and the basic metabolic panel. Liver and kidney function tests sometimes require fasting as well. Your doctor’s office will tell you in advance if fasting is needed. Water is almost always fine to drink during the fasting window.
Quick Reference by Test
- General blood panel: once a year for healthy adults
- Cholesterol (no risk factors): every 4 to 6 years starting at age 20
- Cholesterol (on medication): 4 to 12 weeks after starting, then every 6 to 12 months
- Diabetes screening (overweight adults 35 to 70): every 3 years
- A1C (diagnosed diabetes, stable): every 6 months
- A1C (diagnosed diabetes, not at goal): every 3 months
- Thyroid (on medication, stable): once a year
- Thyroid (new or changed dose): every 6 to 8 weeks until stable
- Warfarin monitoring: every 1 to 12 weeks depending on stability
- Hepatitis C: one-time screening, ages 18 to 79
- HIV: one-time screening, ages 15 to 65