Iron Test
Also known as: Serum Iron, Fe
What is Iron?
Iron is an essential mineral that helps red blood cells carry oxygen throughout the body. It is also important for energy production and immune function.[MedlinePlus (NIH)]
What This Test Measures
This test measures the amount of iron in your blood. It is usually done with ferritin, TIBC, and transferrin saturation for complete iron assessment.[Mayo Clinic]
Why It's Important
Iron deficiency is the most common nutritional deficiency worldwide and causes anemia.[MedlinePlus (NIH)]
Both low and high iron can cause serious health problems.[Cleveland Clinic]
Who Should Get This Test?
Iron testing helps diagnose iron deficiency or overload.
Risk Factors
- Symptoms of anemia (fatigue, weakness, pale skin)
- Heavy menstrual periods
- Pregnancy or planning pregnancy
- Vegetarian or vegan diet
- Recent blood loss or surgery
- Family history of hemochromatosis
- Chronic kidney disease
- Inflammatory bowel disease or celiac disease
Screening Schedule
Not routine for most adults; test when iron deficiency or overload is suspected. Screen for hemochromatosis if family history present.
What Happens During the Test
A blood sample is drawn from a vein, ideally in the morning after fasting. Serum iron is measured using colorimetric assays.
Duration
5-10 minutes for blood draw; results typically available within 1 day
Discomfort Level
Minimal discomfort from needle insertion
Risks & Side Effects
Standard blood draw with minimal risks.
- •Brief pain at needle site
- •Small bruise may develop
- •Rare: lightheadedness
- •Very rare: infection at puncture site
Normal Range
60 to 170 mcg/dL for men. 37 to 170 mcg/dL for women.
Note: Levels vary throughout the day and are highest in the morning.
Source: MedlinePlus (NIH)Unit Conversion
Convert between mcg/dL and μmol/L
| mcg/dL | μmol/L |
|---|---|
| 50 | 8.95 |
| 100 | 17.9 |
| 150 | 26.85 |
| 200 | 35.8 |
| 300 | 53.7 |
High Values
High iron (hemochromatosis) can damage the liver, heart, and pancreas. Causes include genetic hemochromatosis, multiple transfusions, and iron supplements.[Mayo Clinic]
Low Values
Low iron causes fatigue, weakness, pale skin, and iron deficiency anemia. Causes include blood loss, poor diet, malabsorption, and increased needs (pregnancy).[Cleveland Clinic]
Test Limitations & Accuracy
Serum iron alone has limitations:
- ⚠Levels fluctuate significantly throughout the day (highest in morning)
- ⚠Recent iron intake or supplements affect results
- ⚠Inflammation can lower serum iron independent of true iron stores
- ⚠Single measurement is less reliable than complete iron panel
- ⚠Does not reflect total body iron stores (ferritin is better)
- ⚠Fasting state affects accuracy
- ⚠Hemolysis of sample falsely elevates iron
Alternative & Complementary Tests
Iron is typically measured with related tests:
Best measure of total body iron stores
Total Iron Binding Capacity - measures transferrin availability
Calculated from iron and TIBC; percentage of transferrin carrying iron
To assess anemia severity
To assess bone marrow response to iron deficiency
Test Preparation
Fasting for 12 hours is often recommended. Iron levels can vary throughout the day.[MedlinePlus (NIH)]
References
Medical Disclaimer
This information is for educational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for interpretation of test results and medical decisions.
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