How often should I retest my blood biomarkers?

How often to retest blood biomarkers depends on which biomarker, your age, health status, medications, and whether results are normal or changed by treatment or lifestyle. Below are practical, commonly used intervals and reasons, plus recommended lab services you can use.

General principles

• Get a baseline panel once (if you don’t already have one). That helps interpret future change.
• Retest sooner after a treatment or major lifestyle change (medication start/change, new supplement, large weight loss, new diagnosis).
• If results are abnormal or you’re high-risk, test more frequently; if stable and low-risk, test less often.
• Always discuss frequency and interpretation with your clinician before acting.

Suggested intervals for common tests

• Comprehensive metabolic panel (CMP: liver, kidney, electrolytes): baseline, then every 6–12 months if stable; 2–6 weeks after starting or changing meds that affect liver/kidney.
• Lipid panel (cholesterol, LDL, HDL, triglycerides): baseline, 4–12 weeks after starting/changing statin or major diet change, then every 6–12 months until stable, otherwise every 1–4 years for low-risk adults depending on age and guidelines.
• Hemoglobin A1c: every 3 months if diabetic or changing diabetes meds; every 6 months if prediabetic or not at goal; annually if stable and low risk.
• Fasting glucose/insulin: baseline, 3 months after major weight change or med change; frequency similar to A1c.
• Complete blood count (CBC): baseline, then every 6–12 months if stable; sooner (2–8 weeks) if treating anemia or a hematologic condition.
• Thyroid tests (TSH ± free T4): 6–8 weeks after starting or changing thyroid meds, then every 6–12 months if stable.
• High-sensitivity CRP (inflammation): baseline, 4–12 weeks after intervention (weight loss, smoking cessation, meds) to assess change; not useful as a daily measure.
• Ferritin/iron studies: 8–12 weeks after starting iron repletion; baseline and then PRN for monitoring.
• Vitamin D (25-OH): baseline, then 8–12 weeks after starting supplementation to confirm repletion, thereafter 6–12 months if supplementing.
• Testosterone (men) / estradiol (women) and reproductive hormones: baseline; 6–12 weeks after therapy changes, then every 6–12 months.
• PSA (men): follow clinician guidance; often discussed around ages 55–69 and then individualized — commonly checked annually or every 2–4 years depending on risk.
• Advanced or specialized panels (genetic risk, proteomics, metabolomics): baseline and then only as directed by specialist — these are not generally repeated frequently.

Timing/fasting notes

• Fasting (8–12 hours) for glucose and sometimes lipid testing (although many clinics accept non-fasting lipids).
• Draw morning samples for hormones like cortisol and testosterone for more consistent results.

Where to get tests (brands/services)

• Quest Diagnostics or LabCorp — widely available clinical labs accepted by doctors and insurance; good for comprehensive, physician-ordered testing.
• Everlywell or LetsGetChecked — convenient at-home kits for common panels (cholesterol, A1c, thyroid), good for screening and convenience but review results with a clinician.
• InsideTracker or WellnessFX — consumer-focused panels with lifestyle-oriented interpretation and repeat testing programs; good if you want performance/optimization guidance.
• Thorne/Viome — sell targeted or integrative wellness tests (vitamin D, hormones, microbiome—Viome for microbiome); useful for supplement monitoring but interpret carefully.
• SomaLogic or Nightingale Health — advanced proteomics/metabolomics for research or high-end personalized profiling (expensive; not routine).

Additional tips

• After a medication change or starting a supplement, plan a check at the interval listed above (e.g., 6–8 weeks for thyroid, 8–12 weeks for vitamin D).
• Keep a record of testing dates and results so trends are visible.
• If you use a direct-to-consumer lab kit, consider having abnormal or borderline results repeated at a clinical lab (Quest/LabCorp) and reviewed by your clinician.
• Discuss frequency with your primary care provider — they’ll tailor it to your risk profile and insurance considerations.

If you tell me which specific biomarkers you’re tracking, your age and health conditions (or medications), I can give a tailored retesting schedule and suggest the best service for those tests.