Biological Age Blood Tests Combine Nine Routine Markers

The Blood Markers in a Biological Age Blood Test

A biological age blood test estimate relies on nine blood biomarkers and chronological age. Levine et al. (Aging, 2018) built a blood-test measure called Phenotypic Age. The researchers trained their model on data from the Third National Health and Nutrition Examination Survey. A penalized Cox regression narrowed 42 clinical biomarkers to 9 biomarkers plus chronological age. The analytic sample included 9,926 adults with complete biomarker data and over twenty-three years of mortality follow-up.

Table 1 in the study groups the nine markers by physiological system. Albumin and alkaline phosphatase reflect liver function. Creatinine reflects kidney function, while serum glucose represents metabolic function. C-reactive protein measures systemic inflammation. Lymphocyte percent, mean cell volume, red cell distribution width, and white blood cell count reflect immune status. Four markers come from a metabolic panel, four from a complete blood count with differential, and one from a CRP test.

How to Calculate Biological Age from These Markers

You calculate biological age by entering the nine blood results plus your age into Levine's published Phenotypic Age formula after converting US report units. The free biological age calculator does the unit conversion and runs the math in your browser, and it does not store the values you enter.

US lab reports usually print albumin in g/dL, creatinine and glucose in mg/dL, and hs-CRP in mg/L, so a hand calculation converts them first. Multiply albumin in g/dL by 10, creatinine in mg/dL by 88.4017, glucose in mg/dL by 0.0555, and divide CRP in mg/L by 10 before taking its natural log.

A 2019 correction to Liu and colleagues' PLOS Medicine paper states that the equation first printed there "is missing a step which makes it impossible to resolve." A hand calculation therefore needs a correct version of the equation. The calculator also lists which markers move the estimate most.

What Each Marker Measures Across Routine Lab Panels

The nine biomarkers come from standard clinical panels that evaluate metabolic, immune, liver, and kidney health. According to MedlinePlus, a comprehensive metabolic panel is a routine blood test that measures 14 different substances. It includes glucose, albumin, alkaline phosphatase, and creatinine. MedlinePlus notes that albumin is the main protein in your blood and is made in your liver. Albumin keeps fluid from leaking out of blood vessels. Low levels can indicate liver or kidney disease. Glucose serves as your body's main source of energy. Alkaline phosphatase is an enzyme found in all tissues, mainly in the liver, bile ducts, and bones. An alkaline phosphatase test alone cannot identify the source of the enzyme in your blood. Creatinine is a waste product made when muscles break down tissue during activity. Creatinine testing alone is not the best way to evaluate kidney function because muscle mass affects production.

The MedlinePlus complete blood count page states that a CBC measures red cells, white cells, platelets, hemoglobin, and hematocrit. The CBC also reports MCV, the average size of your red blood cells. The MedlinePlus red blood cell indices page lists a normal MCV range of 79 to 95 femtoliters. The MedlinePlus RDW page explains that red cell distribution width measures variation in red blood cell volume and size. An RDW measurement is often part of a routine CBC. For immune markers, the MedlinePlus WBC page notes that white blood cells fight infections. White cell counts rise during illness. The five types are neutrophils, lymphocytes, monocytes, eosinophils, and basophils. The MedlinePlus blood differential page explains that a differential counts each type separately. Lymphocytes include B cells and T cells.

According to MedlinePlus, the liver makes C-reactive protein in response to inflammation. Infections, inflammatory bowel disease, autoimmune disorders, and smoking raise CRP levels. Elevations also link to insomnia, depression, menopausal hormone therapy, and obesity. MedlinePlus says a value of 0.8 to 1.0 milligrams per deciliter or lower is thought to be a healthy amount. An hs-CRP test measures very tiny increases in CRP to evaluate heart disease risk. None of the cited research sources specifies whether the PhenoAge calculation requires a standard CRP or an hs-CRP assay.

How the Research Calculates a Biological Age Score

Researchers calculate phenotypic age by entering nine blood biomarkers and chronological age into a mortality risk equation. Levine et al. combined the nine markers and chronological age in a Gompertz proportional hazards model. The model estimates 10-year mortality risk. That risk is then converted into units of years. In Liu et al. (PLOS Medicine, 2018), Phenotypic Age represents the expected population age corresponding to that mortality risk.

Four of the nine markers come on one routine metabolic panel, and four more come on a CBC with differential. The ninth marker, CRP, requires a separate laboratory order. Researchers built this score to track mortality risk across survey populations without diagnosing individual medical conditions.

Levine et al. validated the equation in the NHANES IV survey of 6,209 adults with up to 12 years of follow-up. In that validation sample, phenotypic age correlated with chronological age at r = 0.94. Adjusting for chronological age, each one-year increase in phenotypic age carried a 9% higher risk of all-cause mortality. Liu et al. evaluated 11,432 adults aged 20 to 84 years, along with 185 adults aged 85 or older. Across 12.6 years of follow-up, 1,012 deaths occurred. Each one-year increase in Phenotypic Age raised mortality risk by 9% (hazard ratio 1.09, 95% CI 1.08 to 1.10). Participants with more diagnosed diseases had an older Phenotypic Age. The authors noted that their analysis lacked longitudinal data on Phenotypic Age and disease incidence.

Biological Age Blood Test Cost and Ordering Options

A biological age blood test using standard panels can be ordered through routine physician checkups or direct-to-consumer lab testing services. A doctor can order a metabolic panel and blood count during routine preventive visits. Online testing services also let individuals purchase these panels directly.

On September 30, 2026, Quest listed a Comprehensive Metabolic Panel Test for $49.00. The test showed a discounted price of $44.10 plus a $6.00 Physician Service Fee. Quest requires fasting for 8 to 12 hours with water permitted. Results are typically available within 1 to 2 business days. Quest also listed an hs-CRP test for $65.00, or $58.50 on sale, plus the $6.00 fee. The hs-CRP test requires no special preparation. Results arrive in 2 to 3 business days.

Labcorp OnDemand listed a Complete Blood Count Test for $29.00. That test includes a differential measuring neutrophils, lymphocytes, monocytes, basophils, and eosinophils. Labcorp OnDemand listed a Comprehensive Metabolic Panel for $49.00. Labcorp requires a 12-hour fast before the blood draw, though water is allowed.

Combining these list prices yields approximately $143 before physician fees or temporary discounts. That sum includes $49 for a CMP, $29 for a CBC with differential, and $65 for hs-CRP. Laboratory prices change over time, and the current figures are on the Quest and Labcorp OnDemand product pages. The online lab testing services comparison and the biomarker testing services guide examine ordering options. The blood test results guide explains how to interpret standard laboratory reports.

Blood-Based Estimates vs Epigenetic Test Kits

Blood-based biological age estimates reflect circulating organ markers, while epigenetic kits measure DNA methylation. Levine et al. trained a 513-CpG-site DNA methylation algorithm called DNAm PhenoAge to predict blood-test Phenotypic Age. In the InCHIANTI study, nine-year changes in phenotypic age correlated with changes in DNAm PhenoAge at r = 0.74. Levine et al. noted that molecular epigenetic measures may capture pre-clinical aging better in young or healthy individuals. Standard blood markers like glucose and creatinine often remain homogenous in healthy young populations.

However, epigenetic clocks carry technical noise. A 2022 study by Higgins-Chen et al. (Nature Aging, 2022) reported deviations up to 9 years between replicate samples across six prominent epigenetic clocks. Their principal-component versions brought most replicates within 1.5 years. In another 2022 study, Belsky et al. (eLife, 2022) evaluated DunedinPACE. They reported test-retest reliability of ICC = 0.96 across 36 replicate blood samples.

Blood-based biological age scores can shift following medical interventions. In a 2026 prospective cohort study, Morawitz et al. (npj Aging, 2026) evaluated 505 bariatric-surgery patients. Twelve months after surgery, participants were an average of 5.55 years younger by phenotypic age calculation. The 95% confidence interval spanned -6.12 to -4.97 years. The reduction remained stable at 24 months. After adjusting for BMI change, the reduction was 3.32 years. This study lacked a non-surgical comparison group. The biological age test guide compares commercial kits, and the epigenetic clock explainer covers how the clocks work. The how to lower biological age guide reviews interventions that have changed scores.

What a Biological Age Blood Test Can and Cannot Tell You

A biological age blood test provides a statistical mortality estimate without diagnosing any medical disease. According to MedlinePlus, abnormal laboratory results do not always indicate a medical condition requiring treatment. Diet, hydration, activity levels, medicines and infections can change blood test results, and an infection can raise white blood cell counts and CRP, according to MedlinePlus. As Liu et al. noted, the research lacks longitudinal data connecting Phenotypic Age changes to specific disease incidence.

This testing does not serve individuals with acute illnesses or people seeking diagnostic screening for specific organ conditions. Standard clinical evaluations by a doctor should address those medical concerns directly. A randomized controlled trial evaluating biological age algorithms against patient health outcomes would clarify their clinical utility.