Learn more about the many tests that exist to check for low iron and anemia.
Testing for low iron is tricky. There are many possible tests (click here for a full list with ranges), which can lead to conflicting results based on how the body uses and stores iron. There is also evidence that medical guidelines underestimate low iron — i.e., people experience low iron symptoms in the “normal” test range. Keep reading to learn how to navigate test options and make an accurate diagnosis.
Can I get tested for low iron?
There are at least eleven blood tests for low iron. These tests measure many aspects of iron, including how much is in your blood, how much is stored in your body, how iron is used to make blood cells, and more.
As a result, multiple test results are required to understand a person’s iron status. It is very common for certain indicators to be normal, while others are suggestive of low iron.
What is a hemoglobin test?
Hemoglobin tests are often the first when checking for low iron. Hemoglobin is an iron-containing protein that enables red blood cells to transport oxygen through the body. Therefore, blood hemoglobin concentration is an indicator of iron status. Low iron can induce low hemoglobin levels; anemia is diagnosed when hemoglobin levels are below 12 g/dl.
However, your body stores iron and may use these reserves to maintain hemoglobin levels despite an iron deficiency. That’s why a normal hemoglobin level does not guarantee sufficient iron.
What is a red blood cell count?
Hemoglobin tests may be lumped into broader tests known as red blood cell counts, which also include measuring the concentration of erythrocytes (mature red blood cells) and reticulocytes (developing red blood cells). Because iron is required for generating new red blood cells, these counts may reduce in the case of low iron. Low iron is indicated by erythrocyte count below 4.2 million cells/ul or reticulocyte count less than 0.5% of the total red blood cells.
What is a complete blood cell count?
A complete blood cell count can additionally inform on the quality of cells. This data may indicate iron deficiency based on cells being deficient. The MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), and MCHC (mean corpuscular hemoglobin concentration) tests inform on average cell size and hemoglobin levels. Low iron is indicated by MCV levels below 80 fl (cells are too small), MCH levels below 27 pg/cell, or MCHC levels below 32 g/dl (cells do not have enough hemoglobin).
What is a serum iron test?
Beyond blood tests, labs can measure your the amount of iron dissolved in your blood. However, the body’s iron levels fluctuate during the course of a day and can be slow to normalize after dietary ingestion. This means that multiple, consistent test results are better than one. Low iron is indicated by serum levels below 60 ug/dl.
What are ferritin, transferrin, and TIBC tests?
The last group of low iron tests we’ll cover measure two special proteins: ferritin and transferrin. Ferritin stores and releases iron. While ferritin is most likely reduced in cases of low iron, it is elevated in certain types of anemia. Low iron is indicated by ferritin levels below 12 ng/ml.
Transferrin regulates the body’s absorption and utilization of freely available iron. Typically, it is elevated in cases of iron deficiency as the body absorbs more iron to compensate for a deficient supply. Low iron is indicated by transferrin levels above 380 mg/dl
Finally, total iron binding capacity (TIBC) and transferrin saturation measure how much iron is bound to your transferrin. Abnormal values indicate the body is not making best use of its iron. Low iron is indicated by TIBC above 450 ug/dl or transferrin saturation below 10%.
What test results indicate low iron levels or anemia?
If you fear you have low iron, the following tests are worth pursuing. With each test, we list the result range indicating low iron. In conjunction with low iron symptoms, being in or near these ranges means it is likely valuable to boost iron levels.
- Hemoglobin count (below 12 g/dl)
- Erythrocyte count (below 4.2 million cells/ul)
- Reticulocyte count (below 0.5% of total cells)
- MCV (below 80 fl)
- MCH (below 27 pg/cell)
- MCHC (below 32 g/dl)
- Serum iron (below 60 ug/dl)
- Serum ferritin (below 25 ng/ml)
- Serum transferrin (above 380 mg/dl)
- TIBC (above 450 ug/dl)
- Transferrin saturation (below 10%)
Sources
- Complete blood count, Erythrocyte count, Serum iron test, and Ferritin blood test (Mount Sinai)
- Low Hemoglobin and Reticulocyte Count (Cleveland Clinic)
- Transferrin (University of Rochester Medical Center)
- Red Cell Indices (Clinical Methods)
- Guide to Diagnosis of Iron Deficiency (World Journal of Gastroenterology)
