Complete Testing & Optimization Guide
Optimal ranges, provider comparison, and strategies to improve your Iron (Serum) levels
Included in 6 of 10 major testing providers
Vitamins &Nutrients
Men:65-175 μg/dL, Women:50-170 μg/dL
Abnormal Iron (Serum) levels can indicate underlying health issues that may go undetected without proper testing. Regular monitoring helps catch problems early when they're most treatable.
Understanding your Iron (Serum) levels enables targeted interventions, tracks treatment effectiveness, and helps optimize your overall health and performance.
Serum iron measures the amount of iron currently circulating in your bloodstream, bound to transferrin (the iron transport protein). Unlike ferritin (which reflects iron stores), serum iron reflects the iron available for immediate use by cells. Serum iron fluctuates significantly throughout the day and is influenced by recent meals, inflammation, and diurnal variation (highest in morning, lowest at night). Because of this variability, serum iron alone is not a reliable marker of iron status—it must be interpreted alongside ferritin, TIBC (total iron-binding capacity), and transferrin saturation.
Here's the critical insight:serum iron, TIBC, and transferrin saturation work together to paint a complete picture of iron status. Low serum iron + high TIBC + low transferrin saturation=iron deficiency (body desperately trying to capture more iron). High serum iron + low TIBC + high transferrin saturation (>45%)=iron overload (hemochromatosis). Normal serum iron + low TIBC=anemia of chronic disease (inflammation sequesters iron). You can't interpret serum iron in isolation—you need the full iron panel.
Transferrin saturation is the most useful calculated value:(Serum Iron / TIBC) × 100. Normal is 20-45%. <20% indicates iron deficiency;>45% suggests iron overload. Transferrin saturation <20% with ferritin <30 ng/mL confirms iron deficiency anemia. Transferrin saturation >45% with ferritin >300 ng/mL (men) or >200 ng/mL (women) suggests hemochromatosis—genetic testing for HFE mutations is warranted.
Bottom line: TSH and Free T4 alone miss people with conversion problems. Free T3 is the only way to know if you have enough active thyroid hormone at the tissue level.
| Range Type | Level | Clinical Significance |
|---|---|---|
| Optimal (with TIBC and Transferrin Saturation) | 60-170 mcg/dL (men) 50-150 mcg/dL (women) | Normal range for serum iron. Must interpret with TIBC and transferrin saturation (optimal 25-35%). |
| Low Serum Iron | <50 mcg/dL | Low serum iron. Check TIBC and ferritin:| If TIBC high (>400) + ferritin low (<30)=iron deficiency. | If TIBC low (<250) + ferritin normal/high=anemia of chronic disease (inflammation). |
| High Serum Iron | >200 mcg/dL | High serum iron. Check TIBC and transferrin saturation:| If transferrin saturation >45% + ferritin >300 (men) or >200 (women)=possible hemochromatosis. | If acute, may be from recent iron supplementation, blood transfusion, or hemolysis. |
| Low Transferrin Saturation | <20% | Iron deficiency. Body can't saturate transferrin with iron. Supplement with iron (ferrous bisglycinate 25-50 mg daily). |
Standard lab range:Men:65-175 μg/dL, Women:50-170 μg/dL
>45%
TIBC (Total Iron-Binding Capacity)
Normal TIBC. High TIBC (>400)=iron deficiency (body makes more transferrin to capture iron). Low TIBC (<250)=chronic inflammation or liver disease.
Serum iron <50 mcg/dL + TIBC >400 + transferrin saturation <20% + ferritin <30 ng/mL=iron deficiency anemia.
Iron supplementation:Ferrous bisglycinate 25-50 mg elemental iron daily (or ferrous sulfate 325 mg once-twice daily). Take with vitamin C, away from calcium/tea/coffee.
Dietary iron:Red meat, organ meats, shellfish (heme iron, highly bioavailable). Vegetarians need 1.8x more iron due to poor non-heme absorption.
Retest in 3 months:Expect ferritin to rise 30-50 ng/mL, transferrin saturation to normalize (>20%).
Both cause low serum iron and anemia, but iron studies distinguish them:
Iron deficiency:Low serum iron, HIGH TIBC (>400), low transferrin saturation (<20%), LOW ferritin (<30). Treat with iron.
Anemia of chronic disease:Low serum iron, LOW TIBC (<250), low-normal transferrin saturation (15-30%), NORMAL or HIGH ferritin (>100). Caused by inflammation (infections, autoimmune disease, cancer) sequestering iron. Treat underlying disease, NOT iron supplementation (can worsen inflammation).
Note: High serum iron + high transferrin saturation (>45%) + high ferritin (>300 men, >200 women)=possible hemochromatosis. | HFE genetic testing:C282Y and H63D mutations. C282Y homozygous=hereditary hemochromatosis (most common). | Phlebotomy:Treatment for hemochromatosis. Remove blood every 1-2 weeks until ferritin drops to 50-100 ng/mL, then maintenance phlebotomy every 2-3 months. | Untreated hemochromatosis causes cirrhosis, diabetes, cardiomyopathy, arthritis, bronze skin, erectile dysfunction.
Note: Serum iron has significant diurnal variation:highest in morning (8-10 AM), lowest at night. Test fasting in the morning for accurate baseline. | Avoid iron supplements for 24 hours before test (can falsely elevate serum iron).
High serum iron with transferrin saturation >45% may indicate hemochromatosis:|Joint pain, especially knuckles (iron deposits in joints)|Fatigue, weakness|Abdominal pain, liver enlargement|Loss of libido, erectile dysfunction|Bronze or gray skin discoloration|Diabetes (iron damages pancreas)|Cirrhosis, liver cancer|Heart arrhythmias, cardiomyopathy|Arthritis, especially hands
Source:High serum iron + high transferrin saturation (>45%) suggests iron overload (hemochromatosis). Requires genetic testing and treatment.
Hereditary hemochromatosis:HFE gene mutations (C282Y, H63D) cause excessive iron absorption from diet. Most common genetic disorder in Caucasians (1:200-300).|Frequent blood transfusions:Chronic anemia (thalassemia, sickle cell) requiring transfusions → iron overload.|Excessive iron supplementation:Taking high-dose iron without deficiency.|Acute iron ingestion:Iron poisoning (accidental or intentional overdose).|Hemolysis:Red blood cell destruction releases iron into bloodstream (hemolytic anemia, transfusion reaction).|Acute hepatitis or liver necrosis:Damaged hepatocytes release stored iron.
Source:Baseline:Order full iron panel (serum iron, TIBC, transferrin saturation, ferritin) if anemia, fatigue, or risk factors for iron deficiency/overload.|Always test in morning, fasting:Serum iron varies by time of day and recent meals.|If low transferrin saturation (<20%) + low ferritin (<30):Confirms iron deficiency. Start iron supplementation, retest in 3 months.|If high transferrin saturation (>45%) + high ferritin (>300 men, >200 women):Evaluate for hemochromatosis. Order HFE genetic testing.|If low serum iron but normal/high ferritin:Consider anemia of chronic disease. Check CRP, ESR to assess inflammation.|Retest after 3 months of iron supplementation:Ferritin should rise 30-50 ng/mL, transferrin saturation normalize to 25-35%.
Transferrin saturation (serum iron / TIBC × 100) is more useful than serum iron alone. <20%=iron deficiency;>45%=iron overload. Transferrin saturation <16% in combination with ferritin <30 ng/mL has 90% sensitivity and specificity for iron deficiency anemia.
Source:Guyatt GH, et al. Laboratory diagnosis of iron-deficiency anemia:an overview. J Gen Intern Med. 1992;7(2):145-153.
Anemia of chronic disease (ACD) is the second most common anemia after iron deficiency. Inflammation (infections, autoimmune disease, cancer) releases hepcidin, which traps iron in macrophages, lowering serum iron but raising/maintaining ferritin. ACD:low serum iron, low TIBC, normal/high ferritin. Iron deficiency:low serum iron, high TIBC, low ferritin.
Source:Weiss G, Goodnough LT. Anemia of chronic disease. N Engl J Med. 2005;352(10):1011-1023.
Hereditary hemochromatosis is diagnosed with transferrin saturation >45% (most sensitive early marker), ferritin >300 (men) or >200 (women), and HFE genetic testing (C282Y homozygous most common). Treatment is phlebotomy:remove 500 mL blood weekly until ferritin <50 ng/mL, then maintenance every 2-3 months. Prevents cirrhosis, diabetes, heart disease.
Source:Bacon BR, et al. Diagnosis and management of hemochromatosis:2011 practice guideline by AASLD. Hepatology. 2011;54(1):328-343.
| Provider | Includes Test | Annual Cost | Total Biomarkers |
|---|---|---|---|
 Superpower | ✓ | $199 | 100+ |
 WHOOP Advanced Labs | — | $349 | 65 |
 Labcorp OnDemand | — | $398 | 30+ |
| — | $486 | 40+ | |
| — | $468 | 83 | |
| ✓ | $798 | 100+ | |
 InsideTracker | ✓ | $680 | 48 |
 Function Health | ✓ | $499 | 100+ |
| ✓ | $900 | 70+ | |
| ✓ | $1150 | 110 | |
| — | $Varies | 75+ |
Choose from 6 providers that include this biomarker in their panels
Iron (Serum) is a vitamins &nutrients biomarker that Iron in blood plasma The normal reference range is Men:65-175 μg/dL, Women:50-170 μg/dL. Regular testing helps track changes and identify potential health issues early.
6 out of 10 major blood testing providers include Iron (Serum) in their standard panels. These include Superpower, Blueprint, Mito Health and others.
For most people, testing Iron (Serum) 2-4 times per year is recommended to establish baseline levels and track trends. If you have abnormal results or are actively working to optimize this biomarker, more frequent testing (quarterly) may be beneficial. Always consult with your healthcare provider for personalized testing frequency recommendations.
The standard laboratory reference range for Iron (Serum) is Men:65-175 μg/dL, Women:50-170 μg/dL. However, many functional medicine practitioners recommend tighter "optimal" ranges for peak health and performance. Your ideal range may vary based on your age, sex, health goals, and other individual factors. Work with a healthcare provider familiar with optimal ranges to determine your target levels.
Most direct-to-consumer blood testing services that include Iron (Serum) provide the physician order as part of their service. However, some states have restrictions on direct-to-consumer testing. Check with your chosen provider about availability in your state and whether they provide the necessary physician authorization.
Measures circulating iron. Low in iron deficiency anemia;high in hemochromatosis. Varies throughout day. Used with ferritin and TIBC to assess iron status.
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs and before making decisions about blood testing.
