Best Biomarkers to Track After 45
Biomarkers worth tracking after 45: blood pressure, ApoB, Lp(a), A1c, kidney and liver markers, with what guidelines say and where evidence is thin.
ACT 2 Health Clinical Team · Updated September 23, 2026
After 45, the most useful health data usually comes from a short list of markers measured more than once, not a long list measured one time. A single result inside a reference range tells you little; the same marker drifting in one direction across three years tells you a lot. The list below favors markers with clear guideline support in midlife, and it says plainly where support is mixed. Tests do not diagnose disease on their own. A clinician reads them against your history and, where it matters, confirms them.
1. Blood pressure
What it is: the pressure in your arteries, measured in the office and, when it reads high, confirmed at home or with a 24-hour ambulatory monitor.
Why it matters after 45: high blood pressure rarely causes symptoms. The USPSTF gives screening an A grade, suggests annual screening from age 40, and recommends confirming a high office reading with measurements outside the clinic before treatment starts.
Practical note: the USPSTF specifies home and ambulatory monitoring with validated, accurate devices. A log of home readings gives your clinician more to work with than one office number.
2. A standard lipid panel, read for non-HDL cholesterol
What it is: total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides. Non-HDL cholesterol is total cholesterol minus HDL.
Why it matters after 45: the 2026 ACC/AHA dyslipidemia guideline brought back LDL-C and non-HDL-C treatment goals and recommends the AHA PREVENT equations, for adults 30 to 79, to estimate 10- and 30-year risk. The lipid panel is still the foundation of that estimate.
Practical note: keep your old results. A panel read against your last three is more informative than one read against a population range.
3. ApoB
What it is: a protein carried once on every atherogenic particle, so an ApoB level is effectively a particle count. More on this in what ApoB is.
Why it matters after 45: the 2026 guideline says ApoB testing can improve risk assessment once LDL-C and non-HDL-C goals are met, particularly with high triglycerides, diabetes or very low LDL-C. MedlinePlus notes that a high ApoB can signal higher risk even when cholesterol looks on target.
Practical note: ApoB is a refinement, not a replacement for LDL-C. It is most useful in the metabolic profile where LDL-C is least reliable: high triglycerides, low HDL, a normal-looking LDL.
4. Lipoprotein(a), once
What it is: an LDL-like particle whose level is largely inherited. Our explainer on Lp(a) covers the basics.
Why it matters after 45: both the 2026 ACC/AHA guideline and the European Atherosclerosis Society consensus say Lp(a) should be measured at least once in adults. The US guideline treats 125 nmol/L (about 50 mg/dL) or higher as a risk-enhancing factor, associated with about a 1.4-fold higher risk.
Practical note: because it is largely genetic and stable, one test is generally enough. A high result is worth sharing with siblings and children.
5. A1c or fasting glucose
What it is: A1c reflects average blood glucose over the past two to three months; fasting glucose is a single-point reading.
Why it matters after 45: the USPSTF recommends screening adults 35 to 70 who have overweight or obesity for prediabetes and type 2 diabetes, and says every 3 years may be reasonable when results are normal. See A1c levels explained.
Practical note: a fasting glucose of 97 is "normal." A climb from 88 to 93 to 97 over three years is a trend worth a conversation.
6. Kidney function: eGFR and urine albumin
What it is: eGFR estimates how well your kidneys filter, from a blood creatinine test. The urine albumin-to-creatinine ratio (UACR) looks for small amounts of protein leaking into urine.
Why it matters after 45: kidney function is part of cardiovascular risk. The PREVENT equations include eGFR and offer UACR as an optional input. MedlinePlus notes that urine albumin can be an early sign of kidney disease and that people with diabetes should be tested every year.
Practical note: eGFR usually comes with a basic metabolic panel. UACR is a separate urine test you may have to ask for if you have high blood pressure, diabetes or heart disease.
7. Liver markers and a FIB-4 score
What it is: ALT and AST are liver enzymes. FIB-4 combines them with age and platelet count to estimate the likelihood of advanced liver scarring.
Why it matters after 45: fatty liver linked to metabolic health often has no symptoms and is usually found through imaging or abnormal liver tests. The AASLD practice guidance uses FIB-4 as the first risk assessment, treats a score below 1.3 as low risk, and suggests repeating it every 1 to 2 years in people with two or more metabolic risk factors, prediabetes or type 2 diabetes.
Practical note: FIB-4 can be calculated from routine labs you may already have. A higher score leads to a second test, such as liver elastography, rather than a diagnosis.
8. hs-CRP
What it is: high-sensitivity C-reactive protein, a marker of low-grade inflammation.
Why it matters after 45: the AHA notes that hs-CRP, alongside Lp(a), ApoB and triglycerides, can be used to refine cardiovascular risk. Support is mixed: the USPSTF found insufficient evidence (an I statement, 2018) to recommend adding it to routine risk assessment.
Practical note: MedlinePlus explains that infection and injury drive inflammation and that smoking can raise CRP. A single high value is usually rechecked before it is read as a baseline.
9. Vitamin B12
What it is: a vitamin needed for nerves and red blood cells.
Why it matters after 45: the NIH Office of Dietary Supplements lists older adults among the groups at higher risk of inadequacy, often because absorption declines, and notes that metformin and acid-reducing medications called proton pump inhibitors can lower B12.
Practical note: worth checking if you take either medication or have numbness, tingling or unexplained fatigue.
10. Morning testosterone, for men with symptoms
What it is: total testosterone, sometimes with free testosterone and SHBG.
Why it matters after 45: MedlinePlus notes that testosterone normally decreases with age, and symptoms such as low libido or fatigue have many causes. The Endocrine Society guideline recommends diagnosing low testosterone only in men with symptoms and consistently low levels, measured on a fasting morning sample and confirmed with a repeat test.
Practical note: an afternoon result, or a single low one, is not enough to act on. This is a test for symptoms, not a screening test for every man.
11. TSH and vitamin D: test with a reason
What it is: TSH is the main screening test for thyroid function; 25-hydroxyvitamin D measures vitamin D status.
Why it matters after 45: both are common add-ons, and both have weak support as routine screens in people without symptoms. The USPSTF found insufficient evidence for thyroid screening in adults without symptoms, and the Endocrine Society suggests against routine vitamin D testing in the general population, including adults 50 to 74. The USPSTF reached an I statement on vitamin D screening too.
Practical note: these are reasonable tests when there is a reason: fatigue, weight change, a medication that affects them, bone loss or a known condition.
Where this fits
ACT 2's guide to blood work explains how a clinician can measure these markers and read them against your own history.
If you want these markers measured and read together over time rather than one at a time, our comparison of biomarker-guided longevity programs looks at who reviews results and how often each service retests, and the list of executive health programs covers the in-person side, including imaging that bloodwork cannot replace.
Sources
- https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/hypertension-in-adults-screening
- https://professional.heart.org/en/science-news/2026-guideline-on-the-management-of-dyslipidemia/top-things-to-know
- https://newsroom.heart.org/news/accaha-issue-updated-guideline-for-managing-lipids-cholesterol
- https://medlineplus.gov/ency/article/003502.htm
- https://eas-society.org/wp-content/uploads/2024/01/ehac361.pdf
- https://medlineplus.gov/lab-tests/lipoprotein-a-blood-test/
- https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/screening-for-prediabetes-and-type-2-diabetes
- https://medlineplus.gov/lab-tests/hemoglobin-a1c-hba1c-test/
- https://pubmed.ncbi.nlm.nih.gov/37947085/
- https://medlineplus.gov/lab-tests/microalbumin-creatinine-ratio/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10735173/
- https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/cardiovascular-disease-screening-using-nontraditional-risk-assessment
- https://medlineplus.gov/lab-tests/c-reactive-protein-crp-test/
- https://medlineplus.gov/lab-tests/testosterone-levels-test/
- https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
- https://pubmed.ncbi.nlm.nih.gov/29562364/
- https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/thyroid-dysfunction-screening
- https://www.endocrine.org/clinical-practice-guidelines/vitamin-d-for-prevention-of-disease
- https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/vitamin-d-deficiency-screening
Frequently asked questions
The tests with the clearest guideline support in midlife are a lipid panel, a one-time Lp(a), an A1c or fasting glucose if you have overweight or obesity, and kidney markers (eGFR, and a urine albumin test if you have risk factors). Blood pressure is not a blood test but belongs on the same list. ApoB, hs-CRP and liver fibrosis scores help in specific groups. A clinician can tell you which apply to you.
It depends on the marker and your results. Lp(a) is largely genetic, so once is generally enough. The USPSTF suggests annual blood pressure screening from age 40 and says screening for diabetes every 3 years may be reasonable when glucose is normal. Markers that are being treated or are drifting are usually rechecked sooner. Your clinician should set the cadence.
Not always. A reference range describes a population, not you. A value that rises year after year while staying inside the range can matter more than a single number. That is why tracking the same markers over time, and reading them against your own history, is more useful than one broad panel.
Not routinely, if you have no symptoms or risk factors. The Endocrine Society suggests against routine vitamin D testing in the general population, and the USPSTF found insufficient evidence to recommend thyroid screening in adults without symptoms. Both are reasonable to test when there is a reason, such as symptoms, a medication or a condition that affects them.
Many direct-to-consumer services let you order lab tests online, but results are only useful when someone interprets them against your history and can act on them. Lab tests do not diagnose disease on their own. If a result is abnormal, you will need a clinician to confirm it and decide what, if anything, to do.
This page is educational and is not medical advice. Treatments are available only to eligible patients following clinical evaluation. How we write and review our content.