Evaluation of iron overload diseases
Evaluation of iron deficiency as a cause of anemia
Immunoturbidimetric Assay
Transferrin (Iron Binding Protein)
TRSF
Serum
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Within 2 hours of collection, centrifuge the specimen.
2. For serum gel tubes, aliquot serum into a plastic vial prior to shipment.
3. For red-top tubes, aliquot the serum into a plastic vial immediately after centrifuging.
If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.
0.5 mL
Gross hemolysis | Reject |
Gross lipemia | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Ambient | 7 days | |
Refrigerated (preferred) | 7 days | ||
Frozen | 180 days |
Evaluation of iron overload diseases
Evaluation of iron deficiency as a cause of anemia
Transferrin is the primary plasma iron transport protein, which binds iron strongly at physiological pH. It is a glycoprotein with an approximate molecular weight of 80 kDa, consisting of a polypeptide strand with two N-glycosidically linked oligosaccharide chains with two homologous binding sites for ferric (Fe 3+) iron serving to keep iron nonreactive in circulation and deliver it to cells with transferrin receptors.
The rate of transferrin synthesis in the liver can be altered according to the body's iron requirements and iron reserves. The circulating concentration increases in response to iron deficiency and decreases in response to iron overload. Transferrin concentration also depends on liver function and nutritional status. It also acts as a negative acute phase reactant, decreasing in concentration in the presence of inflammation; however, it has a minor intraindividual biologic variation of 5%. Transferrin is generally only 25% to 30% saturated with iron. Total iron binding capacity (TIBC) can be estimated from transferrin concentration using the molecular weight of the transferrin and accounting that 1 transferrin molecule can bind 2 atoms of iron.(1)
The degree of iron saturation is a more useful indicator of functional iron depletion or overload than transferrin concentration alone. Serum iron, TIBC, and percent saturation are widely used for the diagnosis of iron deficiency and hemochromatosis. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency. Soluble transferrin receptor performs similarly and is unaffected by inflammation. Reticulocyte hemoglobin has also been used as a sensitive early indicator of iron deficiency and anemia.
200-360 mg/dL
Transferrin concentrations are elevated in anemia of chronic disease and iron overload conditions.(1)
Transferrin concentrations are decreased in iron deficiency, iron deficiency anemia, and iron-refractory iron deficiency anemia.(1)
An elevated transferrin may also occur in pregnancy and with the use of oral contraceptives.
A low transferrin may also occur due to malnutrition, inflammation, liver disease, or nephrotic syndrome.
1. Swinkels DW. Iron metabolism. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 40
2. Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anaemia. Lancet. 2016;387(10021):907-916
Human transferrin forms a precipitate with a specific antiserum, which is determined turbidimetrically.(Package insert: TRSF2 reagent. Roche Diagnostics; v10.0, 04/2022)
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
84466
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
TRSF | Transferrin, S | 3034-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
TRSF | Transferrin, S | 3034-6 |
Change Type | Effective Date |
---|---|
Test Changes - Specimen Information | 2025-03-13 |