# Longevity Blood Test: the 8 Biomarkers That Actually Matter, and Why 'Normal' Is Not 'Optimal'

Eight markers cover most of a longevity blood test: HOMA-IR with fasting insulin, hs-CRP, homocysteine, HbA1c, the Omega-3 Index, ferritin and vitamin D (25-OH-D). Here is the catch. A lab "normal" range only reflects the middle 95% of a population, not your lowest-risk value, so the optimal windows cited in the literature are tighter. Only glucose, fasting insulin and HOMA-IR strictly need a fast of 8 hours. And several "optimal" targets are wellness goals with no outcome-trial behind them.

A lab reference range only tells you whether you sit inside the middle 95% of a population, not whether your value is healthy. Here are eight markers, their tighter optimal window from peer-reviewed literature and the honest places where 'optimizing' does nothing. We sell neither tests nor supplements.

## On this page

- Which Blood Values Actually Matter for a Long Life, and Why 'Normal' Is Not 'Optimal'?
- HOMA-IR and Fasting Insulin: How Do I Catch Insulin Resistance Before Blood Sugar Slips?
- hs-CRP: How High Can Silent Inflammation Be?
- Homocysteine: Elevated, and Is Lowering It Even Worth It? The Honest Answer
- HbA1c: When Is It Prediabetes, and Which Value Is Really Optimal?
- Omega-3 Index: How Much EPA and DHA Sit in Your Red Blood Cells?
- Ferritin and Iron Deficiency: Why 'Within Range' Can Still Mean a Deficiency
- Vitamin D: Deficiency, Optimum, and What the Big VITAL Trial Actually Showed
- Optimal vs. Normal: the Comparison Table for All 8 Markers

## FAQ

- Which blood values should I test for longevity?
- Why is my blood value 'normal' but still not optimal?
- At what HbA1c do I have prediabetes?
- Is it worth lowering elevated homocysteine with B vitamins?
- What is a good Omega-3 Index?
- Is an hs-CRP value below 1 mg/L good?
- At what ferritin do I have iron deficiency?
- Should I test vitamin D, and at what value is it a deficiency?
- Does statutory insurance cover a longevity blood test?

## Sources

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- Pearson TA, Mensah GA, Alexander RW, Anderson JL, Cannon RO 3rd, et al.. (2003). Markers of inflammation and cardiovascular disease: application to clinical and public health practice (AHA/CDC scientific statement). Circulation. https://doi.org/10.1161/01.CIR.0000052939.59093.45
- Matli B, Schulz A, Koeck T, Falter T, Lotz J, Rossmann H, Pfeiffer N, Beutel M, Muenzel T, Strauch K, Wild PS, Lackner KJ. (2021). Distribution of HOMA-IR in a population-based cohort and proposal for reference intervals. Clinical Chemistry and Laboratory Medicine. https://doi.org/10.1515/cclm-2021-0643
- Zhang X, Li J, Zheng S, Luo Q, Zhou C, Wang C. (2017). Fasting insulin, insulin resistance, and risk of cardiovascular or all-cause mortality in non-diabetic adults: a meta-analysis. Bioscience Reports. https://doi.org/10.1042/BSR20170947
- American Diabetes Association Professional Practice Committee. (2024). 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes 2024. Diabetes Care. https://doi.org/10.2337/dc24-S002
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- World Health Organization. (2020). WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. Geneva: World Health Organization. https://www.ncbi.nlm.nih.gov/books/NBK569877/
- English E, Idris I, Smith G, Dhatariya K, Kilpatrick ES, John WG. (2015). The effect of anaemia and abnormalities of erythrocyte indices on HbA1c analysis: a systematic review. Diabetologia. https://doi.org/10.1007/s00125-015-3599-3
- World Health Organization. (2011). Use of Glycated Haemoglobin (HbA1c) in the Diagnosis of Diabetes Mellitus: Abbreviated Report of a WHO Consultation. Geneva: World Health Organization. https://www.ncbi.nlm.nih.gov/books/NBK304271/
- Petersmann A, Mueller-Wieland D, Nauck M, et al. (Deutsche Diabetes Gesellschaft). (2022). Definition, Klassifikation, Diagnostik und Differenzialdiagnostik des Diabetes mellitus: Update 2022 (DDG/DGKL Praxisempfehlung). Die Diabetologie. https://doi.org/10.1007/s11428-022-00997-z
- Hoelzel W, Weykamp C, Jeppsson JO, Miedema K, Barr JR, Goodall I, et al. (IFCC Working Group on HbA1c Standardization). (2004). IFCC reference system for measurement of hemoglobin A1c in human blood and the national standardization schemes in the United States, Japan, and Sweden: a method-comparison study. Clinical Chemistry. https://doi.org/10.1373/clinchem.2003.024802
- Harris WS, von Schacky C. (2004). The Omega-3 Index: a new risk factor for death from coronary heart disease?. Preventive Medicine. https://doi.org/10.1016/j.ypmed.2004.02.030
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- Nicholls SJ, Lincoff AM, Garcia M, Bash D, Ballantyne CM, Barter PJ, Davidson MH, Kastelein JJP, Koenig W, McGuire DK, et al.. (2020). Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk (STRENGTH). JAMA. https://doi.org/10.1001/jama.2020.22258
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_Full guide: https://longevity-germany.com/en/guide/longevity-bluttest-biomarker_

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_Canonical: https://longevity-germany.com/en/guide/longevity-bluttest-biomarker · Part of Longevity Cities · Updated 2026-06-14_