Test ID: FEC
Iron and Total Iron-Binding Capacity, Serum
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Screening for chronic iron overload diseases, particularly hereditary hemochromatosis
Serum iron, total iron-binding capacity, and percent saturation are widely used for the diagnosis of iron deficiency. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.
Method Name A short description of the method used to perform the test
Immunoturbidimetric Assay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Iron (Serum Iron and TIBC) Routine
Iron Binding Capacity (Routine)
Latent Iron Binding Capacity
Transferrin Saturation, Serum
Total Iron-Binding Capacity (TIBC)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 1 mL
Collection Instructions:
1. Fasting (12 hours)
2. Draw blood before 12 noon (preferred).
Additional Information:
1. Patient’s age and sex are required.
2. Iron-containing supplements should be avoided for 24 hours prior to draw.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross OK |
| Icterus | Mild OK; Gross OK |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | 180 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Ingested iron is absorbed primarily from the intestinal tract and is temporarily stored in the mucosal cells as Fe(III)-ferritin. Ferritin provides a soluble protein shell to encapsulate a complex of insoluble ferric hydroxide-ferric phosphate. On demand, iron is released into the blood by mechanisms that are not clearly understood, to be transported as Fe(III)-transferrin.
Transferrin is the primary plasma iron transport protein, which binds iron strongly at physiological pH. Transferrin is generally only 25% to 30% saturated with iron. The additional amount of iron that can be bound is the unsaturated iron-binding capacity (UIBC). The total iron binding capacity (TIBC) can be indirectly determined using the sum of the serum iron and UIBC. Knowing the molecular weight of the transferrin and that each molecule of transferrin can bind 2 atoms of iron, TIBC and transferrin concentration is interconvertible.
Percent saturation (100 x serum iron/TIBC) is usually normal or increased in persons who are iron deficient, pregnant, or are taking oral contraceptive medications. Persons with chronic inflammatory processes, hemochromatosis, or malignancies generally display low transferrin.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
IRON
Males: 50-150 mcg/dL
Females: 35-145 mcg/dL
TOTAL BINDING CAPACITY
250-400 mcg/dL
PERCENT SATURATION
14-50%
Interpretation Provides information to assist in interpretation of the test results
In hereditary hemochromatosis, serum iron is usually >150 mcg/dL and percent saturation is >60%. In advanced iron overload states, the percent saturation often is >90%.
For more information about hereditary hemochromatosis testing, see Hereditary Hemochromatosis Algorithm in Special Instructions.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Measurement of serum iron, iron-binding capacity, and percent saturation should not be used as a test for iron deficiency. It is often unreliable for this purpose.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Tietz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company. 1999
2. Fairbanks VF, Baldus WP: Iron overload. In Hematology. Fourth edition. Edited by WJ Williams, AJ Erslev, MA Lichtman. New York, McGraw-Hill Book Company, 1990, pp 482-505
Method Description Describes how the test is performed and provides a method-specific reference
Under acidic conditions, iron is liberated from transferrin. Lipemic samples are clarified by the detergent. Ascorbate reduces the released Fe(3+) ions to Fe(2+) ions which then react with FerroZine to form a colored complex. The color intensity is directly proportional to the iron concentration and can be measured photometrically.(Package insert: Roche Fe reagent. Indianapolis, IN, 2010)
Anti-transferrin antibodies react with the antigen in the sample to form an antigen/antibody complex. Following agglutination, this is measured turbidimetrically. Addition of polyethylene glycol (PEG) allows the reaction to progress rapidly to the end point and increases sensitivity.(Package insert: Roche TRSF2 reagent. Indianapolis, IN, 2005)
Calculations:
TIBC = (Transferrin x 1.18)
% Saturation = Iron/TIBC x 100
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83540-Iron
83550-Iron-binding capacity
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| IRON | Iron | 2498-4 |
| TIBC | Total Iron Binding Capacity | 2500-7 |
| SAT | Percent Saturation | 14801-5 |
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