Iron Studies: Understanding Anemia and Beyond
Iron is essential for oxygen transport and energy production. Learn how to interpret iron studies and recognize deficiency before anemia develops.
Reference: Iron: 50-170 mcg/dL, Ferritin: 30-300 ng/mL mcg/dL (iron), ng/mL (ferritin)
Key Takeaway
Iron deficiency progresses through stages before anemia appears. Early detection through ferritin testing allows for simpler intervention. Fatigue is often the first symptom—but it's frequently dismissed or attributed to other causes.
What is Iron?
Iron is an essential mineral that plays fundamental roles in your body:
- Oxygen transport - Component of hemoglobin, which carries oxygen in red blood cells
- Energy production - Required for cellular energy metabolism
- DNA synthesis - Essential for cell division and growth
- Immune function - Supports immune cell proliferation and function
- Brain function - Involved in neurotransmitter synthesis
The Iron Deficiency Spectrum
Iron deficiency develops in three stages:
- Iron depletion - Ferritin drops, but hemoglobin is still normal
- Iron-deficient erythropoiesis - Iron supply insufficient for red blood cell production
- Iron deficiency anemia - Hemoglobin drops, fatigue becomes obvious
Most diagnoses happen at stage 3. Earlier detection prevents significant symptoms.
Understanding Your Iron Panel
Iron testing typically includes multiple markers:
| Test | What It Measures | Pattern in Deficiency | |
|---|---|---|---|
| Ferritin | Iron stores | First to drop, most sensitive marker | Low (earliest sign) |
| Serum Iron | Circulating iron | Varies throughout day | Low or normal |
| TIBC/Transferrin | Iron transport capacity | Increases when iron is low | High |
| Transferrin Saturation | % of transport proteins filled | Reflects available iron | Low (＜20%) |
| Hemoglobin | Oxygen-carrying protein | Last to drop in deficiency | Low (late stage) |
| Source: Clinical guidelines and literature review | |||
Understanding Your Results
Reference Range
Ferritin Interpretation Challenge
Ferritin is an "acute phase reactant"—it increases with inflammation, infection, or liver disease. This means ferritin can appear normal or high even when iron stores are low. In inflammatory conditions, ferritin levels above 100 ng/mL may still represent iron deficiency. Clinical context is essential.
What Your Levels Mean
Risk Factors for Iron Deficiency
Who's at Risk for Iron Deficiency?
| Factor | Effect | What to Do |
|---|
Always tell your doctor about medications, supplements, and recent health events before testing.
Signs of Iron Deficiency
Common Iron Deficiency Symptoms
These often appear before anemia develops
The Pica Connection
Craving and eating non-food substances (pica) is a classic sign of iron deficiency. Ice craving (pagophagia) is the most common. The craving typically resolves within days to weeks of starting iron treatment. If you crave ice, soil, clay, or paper, get your iron checked.
Optimizing Iron Levels
Dietary Sources
Heme iron (from animal sources) is 2-3 times more bioavailable than non-heme iron:
- Shellfish - Oysters, clams, mussels (highest concentrations)
- Organ meats - Liver, especially beef and chicken liver
- Red meat - Beef, lamb, venison
- Poultry - Dark meat chicken and turkey
- Fish - Sardines, tuna, salmon
Your body absorbs 15-35% of heme iron.
Supplementation
Forms of iron supplements:
- Ferrous sulfate - Most common, inexpensive, well absorbed. Can cause digestive upset.
- Ferrous gluconate - Less concentrated, slightly better tolerated.
- Ferrous fumarate - Higher concentration, good option if multiple tablets needed.
- Iron polysaccharide - May cause fewer side effects but less studied.
Dosing tips:
- Take on empty stomach for best absorption (but take with food if causes upset)
- Take with vitamin C (orange juice, supplement) to boost absorption
- Avoid tea, coffee, dairy, and antacids for 2 hours before/after
- Liquid iron absorbs better but can stain teeth
Typical dose: 325 mg ferrous sulfate (65 mg elemental iron) 2-3 times daily for deficiency.
Related Biomarkers
🔗Related Biomarkers
When Iron is Too High
Hereditary hemochromatosis affects ~1 in 200 people of Northern European descent. The body absorbs too much iron from food, slowly accumulating in organs:
Symptoms of iron overload:
- Fatigue (similar to deficiency!)
- Joint pain (especially knuckles)
- Abdominal pain
- Skin discoloration (bronze/gray)
- Diabetes ("bronze diabetes")
- Liver disease
Treatment: Regular phlebotomy (blood removal) reduces iron stores. This is one condition where being a frequent blood donor is therapeutic. If ferritin is persistently elevated (＞300 ng/mL men, ＞200 ng/mL women), get tested for hemochromatosis.
Frequently Asked Questions
Track Your Health Journey
Monitor your biomarkers over time to understand your health trends.