What Blood Tests Should I Get Annually?

Medical guidelines from organizations like the American Heart Association, the American Diabetes Association, and the U.S. Preventive Services Task Force converge on a core set of tests that every adult should get regularly. These tests catch the most common — and most treatable — health conditions before symptoms appear.

Complete Blood Count (CBC). This test measures your red blood cells, white blood cells, hemoglobin, hematocrit, and platelets. It can detect anemia, infection, immune disorders, and blood cancers. It's the single most ordered blood test in medicine and provides a broad snapshot of your body's baseline function.

Comprehensive Metabolic Panel (CMP). The CMP measures 14 markers including blood glucose (diabetes risk), BUN and creatinine (kidney function), ALT and AST (liver function), and electrolytes like sodium, potassium, and calcium. Abnormalities here can catch kidney disease, liver damage, and metabolic disorders early — often years before symptoms develop.

Lipid Panel. Total cholesterol, LDL ("bad" cholesterol), HDL ("good" cholesterol), and triglycerides. Heart disease remains the #1 cause of death in the United States, and lipid levels are one of the strongest modifiable risk factors. The AHA recommends lipid screening every 4–6 years for average-risk adults, but annual testing is wise if you have any risk factors.

Hemoglobin A1c. This test reflects your average blood sugar over the past 2–3 months and is the gold standard for screening prediabetes and diabetes. Over 96 million American adults have prediabetes, and 80% don't know it. An annual A1c is one of the most impactful screening tests available.

Thyroid Stimulating Hormone (TSH). Thyroid disorders affect an estimated 20 million Americans, and up to 60% of those with thyroid disease are unaware of their condition. A simple TSH test screens for both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid), which can affect energy, weight, mood, and heart function.

Beyond the core panel, your age, sex, family history, and lifestyle can make certain additional tests especially valuable:

Adults under 40:

• Vitamin D — Deficiency is extremely common (estimated 40% of U.S. adults) and linked to fatigue, bone loss, weakened immunity, and mood disorders. Especially important if you live in a northern climate, work indoors, or have darker skin.
• Iron panel — Particularly important for menstruating women and vegetarians/vegans who may be at higher risk for iron deficiency anemia.
• Vitamin B12 — Critical for nerve function and red blood cell production. Deficiency is common in vegetarians, vegans, and those taking certain medications like metformin or PPIs.

Adults 40–60:

• C-Reactive Protein (CRP) — A marker of systemic inflammation that independently predicts cardiovascular risk. Increasingly recognized as important alongside traditional lipid testing.
• PSA (men over 50) — Prostate-specific antigen screening for prostate cancer. Discuss timing with your doctor, but a baseline at 50 (or 40–45 for high-risk men) is generally recommended.
• Expanded thyroid panel — Adding Free T4 and Free T3 to TSH provides a more complete picture of thyroid function, which becomes more relevant as thyroid disorders increase with age.

Adults over 60:

• Vitamin B12 — Absorption decreases with age, and deficiency can mimic cognitive decline and dementia symptoms.
• Comprehensive metabolic monitoring — Kidney and liver function become increasingly important to track, especially if taking medications metabolized by these organs.
• Hemoglobin A1c — Type 2 diabetes risk increases significantly with age. Annual monitoring is essential.

Women specifically should consider thyroid testing more frequently (thyroid disorders are 5–8x more common in women), iron studies (due to menstrual blood loss), and hormone panels during perimenopause and menopause.

Men specifically should prioritize cardiovascular markers (heart disease risk rises sharply after 45), testosterone (which naturally declines about 1% per year after 30), and PSA screening as recommended by their physician.

The right testing frequency depends on your health status, risk factors, and goals. Here are evidence-based guidelines:

Once per year (minimum for most adults): A comprehensive panel covering CBC, CMP, lipid panel, A1c, and TSH provides an annual health snapshot. This is the standard of care that most physicians recommend during annual physicals. If you're generally healthy with no known risk factors, once a year is sufficient for these core tests.

Every 6 months: If you're actively managing a health condition (e.g., prediabetes, high cholesterol, thyroid disorder), more frequent testing helps you and your doctor assess whether lifestyle changes or medications are working. This is also appropriate if you've recently made significant dietary or exercise changes and want to measure the impact.

Every 3–4 months: For people with diabetes, hemoglobin A1c every 3 months is the clinical standard, since A1c reflects a 2–3 month glucose average. Similarly, if you've recently started or changed medications that affect liver or kidney function, more frequent metabolic panels may be appropriate.

The value of regular testing isn't just in any single result — it's in the trend. A cholesterol level of 210 means something different if it was 190 last year (trending up — worth investigating) versus 230 last year (trending down — lifestyle changes are working). Your TestWell dashboard tracks your results over time, making it easy to spot trends that a single test would miss.

Starting annual testing in your 20s or 30s establishes a baseline that becomes invaluable as you age. You'll know what's normal for you, not just what's within the population reference range. Many health changes are detectable years before they cross the "abnormal" threshold — but only if you have prior results to compare against.

Lab results can seem intimidating at first glance, but understanding the basics is simpler than you think. Here's a framework for interpreting your annual blood work:

Reference ranges. Every test result comes with a reference range — the values considered normal for the general population. These ranges are established by testing thousands of healthy individuals and identifying the middle 95%. Results within range are generally normal; results outside range warrant attention but aren't necessarily cause for alarm.

Context matters. A single out-of-range result doesn't necessarily indicate a problem. Temporary factors like dehydration, recent exercise, fasting status, medications, time of day, and even stress can all affect lab values. Mildly abnormal results are often repeated to confirm before any clinical action is taken.

Trends over time. The most powerful insight comes from tracking the same markers over time. Your TestWell dashboard shows historical trends for every marker, so you can see whether a value is stable, improving, or moving in a concerning direction. A gradually rising fasting glucose over three years, for example, is a clear early warning sign for prediabetes — even if each individual result is still within the "normal" range.

What to do with your results:

• All results in range: Great — save these as your baseline and retest in 12 months.
• Mildly out of range (flagged as "slightly high" or "slightly low"): Review the specific marker, consider lifestyle factors, and consider retesting in 3–6 months. Our Lab Agent can help explain what each marker means.
• Significantly out of range: Schedule a follow-up with a healthcare provider. Bring your TestWell results — they're in standard lab report format that any doctor can read. Early detection of conditions like diabetes, kidney disease, and thyroid disorders can dramatically improve outcomes.

TestWell provides clear explanations alongside every result, including what each marker measures, common causes of abnormal values, and when to seek medical advice. Our goal is to empower you with information — not to replace your relationship with a healthcare provider, but to help you be a more informed participant in your own health.