Transferrin Decreased
Decreased transferrin levels in your blood can signal important health conditions. This protein, produced by your liver, plays a crucial role in transporting iron throughout your body, and when levels drop, it may indicate problems ranging from liver disease to chronic inflammation.
Table of contents
- What is transferrin
- Normal range for transferrin levels
- Causes of decreased transferrin
- Related symptoms and conditions
- How transferrin is tested
- Understanding your test results
What is transferrin
Transferrin is a blood protein that acts as the main carrier of iron in your body. Your liver produces this protein, which has the important job of binding to iron and delivering it to tissues such as the liver, spleen, and bone marrow.[1] Nearly all the iron in your body is normally attached to transferrin.[2]
Transferrin is a glycoprotein with a molecular weight of 80 kDa. It can bind up to two atoms of ferric iron (Fe3+) with high affinity.[1] Once iron is bound to transferrin, it is transported throughout your body to where it’s needed, particularly to the bone marrow for the production of hemoglobin, the substance that helps your red blood cells carry oxygen.[1]
The amount of transferrin in your blood depends on your liver function and nutritional status.[4] Transferrin is what doctors call a negative acute phase protein, which means that when inflammation occurs in your body, the liver decreases its production of transferrin while increasing production of other inflammation-related proteins.[8]
Normal range for transferrin levels
In healthy people, transferrin levels normally range between 200 and 370 milligrams per deciliter (mg/dL).[8] Some sources cite the normal range as 215 mg/dL to 380 mg/dL.[2] Levels may vary slightly between laboratories due to differences in equipment, techniques, and chemicals used.[8]
Transferrin can also be measured indirectly using a value called total iron-binding capacity (TIBC), which measures the total amount of iron that can be bound by transferrin proteins in the blood.[4] Normal TIBC values are 250 micrograms per deciliter (mcg/dL) to 450 mcg/dL.[2]
Causes of decreased transferrin
If you have a lower level of transferrin than normal, you may have one of several different health problems. The most common causes of decreased transferrin include:[2][5]
- Liver disease
- Hemolytic anemia
- Chronic infection
- Extensive malignancy
- Tissue inflammation states
- Uremia
- Nephrotic syndrome
Transferrin is produced in the liver, so its levels are closely associated with liver health.[8] Because transferrin is a negative acute phase protein, with inflammation the liver increases production of inflammation-associated proteins (such as C-reactive protein and ferritin) while it decreases production of transferrin.[8]
In pregnancy, protein levels including transferrin are increased. However, because iron demands rise, late pregnancy often shows low serum iron, elevated TIBC, and reduced transferrin saturation.[3]
Related symptoms and conditions
Low transferrin levels may be part of a broader picture of health problems. When transferrin is decreased, it often occurs alongside other changes in iron-related tests. In conditions involving chronic inflammation or disease, you might experience:[2]
- Unexplained weakness
- Unexplained fatigue or lack of energy
- Pale or yellowish skin color
- Dizziness
- Irritability
- Headaches, especially with activity
It’s important to note that decreased transferrin is different from iron deficiency. In iron-deficiency anemia, transferrin levels actually increase as your body tries to compensate by making more transferrin to capture and transport whatever iron is available.[8] When transferrin is decreased, it typically indicates a different set of health issues, particularly those involving liver function or chronic inflammation.[8]
How transferrin is tested
The test for transferrin is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.[2] You may need to fast for a period of time before the test, so check with your doctor for specific instructions.[2]
Iron tests (including ferritin, iron, transferrin, and iron-binding capacity) are ideally drawn early in the morning, after a 12-hour fast, when serum iron values are at their highest. This is because iron levels show daily variation, with values being lowest in the evening.[3]
Certain factors can affect your test results. Medications should be noted, particularly if you are taking multivitamins with iron or oral contraceptives.[3] Aspirin, antibiotics, and birth control pills can affect your results.[2] Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking.[2]
Hemolysis during blood specimen collection may invalidate the accuracy of iron tests.[3] Iron tests may also be less reliable if drawn within 4 days to 1 week of a blood transfusion.[3]
Understanding your test results
Your doctor will interpret your transferrin results by taking into account your medical history, symptoms, and other test results.[8] Transferrin is typically measured as part of a group of tests known as iron studies, which includes other tests relating to the body’s iron levels.[4]
Your doctor may also order other tests along with transferrin measurement, including:[2]
- A complete blood count (CBC)
- Tests to measure how much iron is in your blood
- A test to measure ferritin, a protein that holds most of your body’s iron reserves
- Stool tests
The results of these tests, combined with other information, can help your doctor determine the cause of your symptoms and the appropriate treatment.[2] Many different health conditions can cause high or low levels of transferrin, so the complete picture from all your tests is important for an accurate diagnosis.[2]
Studies suggest that both high and low transferrin saturation levels have been associated with an increase in all-cause mortality. Abnormal transferrin saturation levels may be accompanied by raised inflammatory markers such as C-reactive protein.[3]
