Optimal Blood Test Results

Reference Ranges vs. Optimal Ranges

Standard Reference Ranges are typically derived from the "average" population (the middle 95%). Since the average population often has underlying health issues, "normal" does not always mean "healthy."

Optimal Ranges are targets associated with the lowest all-cause mortality and best physiological function. These tight ranges (advocated by researchers like Dr. Mike Lustgarten) aim for maximizing longevity rather than just avoiding acute disease.

Marker	Standard (US)	Standard (SI/EU)	Optimal Range	Notes
Fasting Glucose Metabolic	70 - 99 mg/dL	3.9 - 5.5 mmol/L	75 - 85 mg/dL (4.2 - 4.7 mmol/L)	Lower end of normal is associated with better longevity. Avoid spikes.
HbA1c Metabolic	< 5.7%	< 39 mmol/mol	4.5 - 5.1%	Measure of average blood sugar. Lower values generally better unless hypoglycemic.
Fasting Insulin Metabolic	2.6 - 24.9 uIU/mL	18 - 173 pmol/L	2 - 5 uIU/mL	Critical marker. Low fasting insulin suggests good insulin sensitivity.
LDL-C Lipids	< 100 mg/dL	< 2.6 mmol/L	50 - 70 mg/dL (1.3 - 1.8 mmol/L)	Many lipidologists argue closer to 50 is better for regression of atherosclerosis.
HDL-C Lipids	> 40 mg/dL (Men), > 50 (Women)	> 1.0 mmol/L (Men), > 1.3 (Women)	60 - 80 mg/dL (1.5 - 2.1 mmol/L)	Functional HDL is key. Extremely high levels (>90) may not be protective.
Triglycerides Lipids	< 150 mg/dL	< 1.7 mmol/L	< 80 mg/dL (< 0.9 mmol/L)	Sensitive to diet (carbs/alcohol). Ideally ratio of Trig/HDL is < 1.
ApoB Lipids	< 90 mg/dL	< 0.9 g/L	< 60 mg/dL	More accurate predictor of CVD risk than LDL-C alone.
hs-CRP Inflammation	< 2.0 mg/L	< 2.0 mg/L	< 0.5 mg/L	High Sensitivity C-Reactive Protein. General systemic inflammation.
Homocysteine Inflammation	< 15 umol/L	< 15 umol/L	6 - 9 umol/L	Methylation marker. High levels damage blood vessels. Requires B6/B12/Folate.
Fibrinogen Inflammation	200 - 400 mg/dL	2 - 4 g/L	200 - 300 mg/dL	Clotting factor and inflammation marker.
Vitamin D (25-OH) Vitamins/Minerals	30 - 100 ng/mL	75 - 250 nmol/L	40 - 60 ng/mL (100 - 150 nmol/L)	Critical for immunity, mood, bone health. Some experts argue for 40-80 ng/mL.
Ferritin Vitamins/Minerals	30 - 400 ng/mL	30 - 400 ug/L	50 - 150 ng/mL	Iron storage. Too high (>200) indicates inflammation/oxidative stress. Too low (<50) impacts energy.
Testosterone (Total) Hormones	264 - 916 ng/dL (Men)	9.2 - 31.8 nmol/L	600 - 900 ng/dL (Men)	Highly variable by age. Optimal range is debated but generally upper quartile of reference.
Testosterone (Free) Hormones	46 - 224 pg/mL	160 - 777 pmol/L	150 - 250 pg/mL	Bioavailable testosterone. Often more important than Total T for symptoms.
Estradiol (E2) Hormones	10 - 40 pg/mL (Men)	37 - 147 pmol/L	20 - 30 pg/mL (Men)	Balance consists of T:E ratio. Too low causes joint/bone/libido issues.
SHBG Hormones	16 - 55 nmol/L (Men)	16 - 55 nmol/L	30 - 40 nmol/L	Sex Hormone Binding Globulin. Regulates free hormones.
ALT (Alanine Aminotransferase) Liver	0 - 44 IU/L	0 - 44 IU/L	15 - 25 IU/L	Liver enzyme. Higher levels indicate liver stress/damage.
AST (Aspartate Aminotransferase) Liver	0 - 40 IU/L	0 - 40 IU/L	15 - 25 IU/L	Liver/Muscle enzyme. Ideally close to ALT.
GGT Liver	0 - 60 IU/L	0 - 60 IU/L	< 20 IU/L	Gamma-Glutamyl Transferase. Sensitive marker for oxidative stress and alcohol.
Creatinine Kidney	0.7 - 1.3 mg/dL	60 - 110 umol/L	0.8 - 1.1 mg/dL	Kidney function. Dependent on muscle mass.
Albumin Liver	3.5 - 5.5 g/dL	35 - 55 g/L	4.5 - 5.0 g/dL	Major protein in blood. High levels associated with longevity (Lustgarten).
Hemoglobin CBC	13.5 - 17.5 g/dL (Men)	135 - 175 g/L	14.5 - 15.5 g/dL	Oxygen carrying capacity.
Hematocrit CBC	38.8 - 50.0%	0.388 - 0.500	44 - 48%	Percentage of red blood cells in volume. Coordinates with Hemoglobin.
Red Blood Cell Count (RBC) CBC	4.32 - 5.72 m/uL	4.32 - 5.72 T/L	4.5 - 5.5 m/uL	Core marker for oxygen transport.
MCV CBC	80 - 100 fL	80 - 100 fL	85 - 92 fL	Mean Corpuscular Volume. High > B12/Folate deficiency. Low > Iron deficiency.
RDW CBC	11 - 15%	11 - 15%	< 12.6%	Red Cell Distribution Width. Strong predictor of all-cause mortality (Lustgarten). Lower is better.
Platelets CBC	150 - 450 k/uL	150 - 450 G/L	175 - 250 k/uL	Clotting. Lower end of normal often associated with longevity (reduced thrombotic risk).
WBC CBC	3.5 - 10.5 k/uL	3.5 - 10.5 G/L	3.5 - 6.0 k/uL	White Blood Cells. Chronic high-normal levels may indicate low-grade inflammation.
TSH Thyroid	0.4 - 4.5 uIU/mL	0.4 - 4.5 mIU/L	0.5 - 2.5 uIU/mL	Thyroid Stimulating Hormone. Functional medicine targets a tighter range.
Free T3 Thyroid	2.0 - 4.4 pg/mL	3.1 - 6.8 pmol/L	3.0 - 4.0 pg/mL	Active thyroid hormone. Upper half of reference range usually optimal.
Free T4 Thyroid	0.8 - 1.8 ng/dL	10 - 23 pmol/L	1.0 - 1.5 ng/dL	Storage thyroid hormone.
Reverse T3 Thyroid	8 - 25 ng/dL	12 - 38 ng/dL	< 15 ng/dL	Inactive form. High levels indicate stress/inflammation blocking T4->T3 conversion.
BUN (Blood Urea Nitrogen) Kidney	6 - 20 mg/dL	2.1 - 7.1 mmol/L	10 - 15 mg/dL	Protein metabolism waste product. Low < 10 may indicate low protein intake.
Cystatin C Kidney	0.62 - 1.15 mg/L	0.62 - 1.15 mg/L	< 0.9 mg/L	Superior marker for eGFR than creatinine, unaffected by muscle mass.
Uric Acid Metabolic	3.5 - 7.2 mg/dL	208 - 428 umol/L	< 5.5 mg/dL	High levels linked to metabolic syndrome and gout. Dr. Perlmutter advises < 5.5.
Serum Iron Vitamins/Minerals	65 - 175 mcg/dL	11.6 - 31.3 umol/L	85 - 130 mcg/dL	Circulating iron.
TIBC Vitamins/Minerals	250 - 450 mcg/dL	45 - 81 umol/L	250 - 350 mcg/dL	Total Iron Binding Capacity.
Transferrin Saturation Vitamins/Minerals	15 - 50%	0.15 - 0.50	30 - 40%	Critical marker. Saturation < 20% indicates deficiency, > 45% potential overload (Hemochromatosis).
Vitamin B12 Vitamins/Minerals	232 - 1245 pg/mL	171 - 920 pmol/L	> 600 pg/mL	Neurological health. Japan uses 500 as the lower cutoff.
Folate (Serum) Vitamins/Minerals	> 3.0 ng/mL	> 7 nmol/L	> 10 ng/mL	Methylation.
Calcium (Serum) Vitamins/Minerals	8.6 - 10.3 mg/dL	2.15 - 2.55 mmol/L	9.2 - 9.9 mg/dL	Tightly regulated. High levels may indicate parathyroid issues.
Magnesium (RBC) Vitamins/Minerals	4.2 - 6.8 mg/dL	1.7 - 2.8 mmol/L	6.0 - 6.5 mg/dL	RBC Magnesium is more accurate for tissue status than Serum Magnesium.