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24888 Iron, Liver Tissue (FET)

Iron, Liver Tissue (FET)
Test Code: FELVRSO
Synonyms/Keywords
​Ref Lab Code: 8350, Fe (Iron), Hemochromatosis, Hepatic Iron Concentration, Hepatic Iron Index, Iron (Fe), Iron, Tissue Liver, Metals, Tissue,
Quantitative Iron, Total Iron, Liver Tissue
Useful For
Diagnosis of hemochromatosis
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Liver Tissue​ ​Mayo metal-free specimen vial (blue label) Paraffin block, if not more than 1 or 2 cuts have been made to it for slides. 2 mg​
2 cm (22-gauge needle), 1 cm (18-gauge needle), or 2 mm x 2 mm (punch) 0.3 mg by dry weight​
 ​
Collection Processing Instructions
1. 2 mg of liver tissue is required. This is typically a piece of tissue from a 22-gauge needle biopsy at least 2 cm long. If an 18-gauge needle is used, the tissue must be at least 1 cm in length.
2. Any specimen vial other than a Mayo metal-free vial used should be plastic, leached with 10% nitric acid for 2 days, rinsed with redistilled water, and dried in clean air.
Additional Information:
1. Patient's date of birth is required to calculate iron index.
2. If tissue is other than liver tissue, see MSCM/20522 Miscellaneous Metals Testing.
3. Paraffin blocks will be returned 3 days after analysis.​
Specimen Stability Information
Specimen Type Temperature
​Liver Tissue ​Refrigerated (preferred)
​ ​Ambient
​ ​Frozen
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories​ ​Monday through Friday ​2 days/3 days if repeat testing required
Dynamic Reaction Cell-Inductively Coupled Plasma-Mass Spectrometry (DRC-ICP-MS)​
Reference Lab
Mayo Clinic Laboratories
Test Information
Useful for diagnosis of hemochromatosis. A hepatic iron concentration >10,000ug/d dry weight is diagnostic for hemochromastosis. Hepatic iron concentrations >3,000ug/d are seen when there is iron overload without cellular injury and cirrhosis. Hepatic iron concentrations greater than the reference range are associated with hemosiderosis, thalassemia, and sideroblastic anemia. Some patients with hepatitis or cirrhosis without significant fibrosis will have hepatic iron concentrations at the top end of normal or just slightly above the normal range.​
Reference Range Information
Iron:
    Males: 200-2,400 mcg/g dry weight
    Females: 400-1,600 mcg/g dry weight
Iron Index: <1.0 mcmol/g/year (>=13 yr)
Reference values have not been established for patients that are less than 13 years of age.
Interpretation
​
A hepatic iron concentration >10,000 mcg/g dry weight is diagnostic for hemochromatosis.
 
Hepatic iron concentrations >3,000 mcg/g are seen when there is iron overload without cellular injury and cirrhosis. Hepatic iron concentrations greater than the reference range are associated with hemosiderosis, thalassemia, and sideroblastic anemia. Some patients with hepatitis or cirrhosis without significant fibrosis will have hepatic iron concentrations at the top end of normal or just slightly above the normal range.
 
Iron accumulates in the liver normally with aging. The hepatic iron index (HII) normalizes hepatic iron concentration for age. The HII is calculated from the hepatic iron concentration by converting the concentration from mcg/g to mcmol/g dry weight and dividing by years of age. The normal range for HII is <1.0. Patients with homozygous hemochromatosis have HII >1.9. Patients with heterozygous hemochromatosis often have HII ranging from 1.0 to 1.9. Patients with hepatitis and alcoholic cirrhosis usually have HII <1.0, although a small percentage of patients with alcoholic cirrhosis have HII in the range of 1.0 to 1.9. Patients with hemochromatosis who have been successfully treated with phlebotomy will have HII <1.0.
 
Liver specimens collected from patients with cirrhosis containing a high degree of fibrosis have results near the low end of the reference range, even though they will show significant iron staining in hepatocytes. While it is true that iron accumulates in hepatocytes in advanced alcoholic cirrhosis with fibrosis, there are relatively few hepatocytes compared to other inert (fibrotic) tissue, so the quantitative iron determination, which is expressed as mcg of iron per gram of dry weight tissues, yields a low result. Histologic examination of all tissue specimens should be performed to facilitate correct interpretation. When structural heterogeneity is apparent histologically, variation in measured iron should be anticipated. We have observed, in approximately 2% of cases, a high degree of hepatic heterogeneity that makes quantitation highly variable.
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​83540 ​ ​ ​ ​
Synonyms/Keywords
​Ref Lab Code: 8350, Fe (Iron), Hemochromatosis, Hepatic Iron Concentration, Hepatic Iron Index, Iron (Fe), Iron, Tissue Liver, Metals, Tissue,
Quantitative Iron, Total Iron, Liver Tissue
Ordering Applications
Ordering Application Description
​Centricity ​Iron, Liver Tissue (8350)
​Cerner ​Iron Level Liver Tissue (8350)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Liver Tissue​ ​Mayo metal-free specimen vial (blue label) Paraffin block, if not more than 1 or 2 cuts have been made to it for slides. 2 mg​
2 cm (22-gauge needle), 1 cm (18-gauge needle), or 2 mm x 2 mm (punch) 0.3 mg by dry weight​
 ​
Collection Processing
1. 2 mg of liver tissue is required. This is typically a piece of tissue from a 22-gauge needle biopsy at least 2 cm long. If an 18-gauge needle is used, the tissue must be at least 1 cm in length.
2. Any specimen vial other than a Mayo metal-free vial used should be plastic, leached with 10% nitric acid for 2 days, rinsed with redistilled water, and dried in clean air.
Additional Information:
1. Patient's date of birth is required to calculate iron index.
2. If tissue is other than liver tissue, see MSCM/20522 Miscellaneous Metals Testing.
3. Paraffin blocks will be returned 3 days after analysis.​
Specimen Stability Information
Specimen Type Temperature
​Liver Tissue ​Refrigerated (preferred)
​ ​Ambient
​ ​Frozen
Useful For
Diagnosis of hemochromatosis
Reference Range Information
Iron:
    Males: 200-2,400 mcg/g dry weight
    Females: 400-1,600 mcg/g dry weight
Iron Index: <1.0 mcmol/g/year (>=13 yr)
Reference values have not been established for patients that are less than 13 years of age.
Interpretation
​
A hepatic iron concentration >10,000 mcg/g dry weight is diagnostic for hemochromatosis.
 
Hepatic iron concentrations >3,000 mcg/g are seen when there is iron overload without cellular injury and cirrhosis. Hepatic iron concentrations greater than the reference range are associated with hemosiderosis, thalassemia, and sideroblastic anemia. Some patients with hepatitis or cirrhosis without significant fibrosis will have hepatic iron concentrations at the top end of normal or just slightly above the normal range.
 
Iron accumulates in the liver normally with aging. The hepatic iron index (HII) normalizes hepatic iron concentration for age. The HII is calculated from the hepatic iron concentration by converting the concentration from mcg/g to mcmol/g dry weight and dividing by years of age. The normal range for HII is <1.0. Patients with homozygous hemochromatosis have HII >1.9. Patients with heterozygous hemochromatosis often have HII ranging from 1.0 to 1.9. Patients with hepatitis and alcoholic cirrhosis usually have HII <1.0, although a small percentage of patients with alcoholic cirrhosis have HII in the range of 1.0 to 1.9. Patients with hemochromatosis who have been successfully treated with phlebotomy will have HII <1.0.
 
Liver specimens collected from patients with cirrhosis containing a high degree of fibrosis have results near the low end of the reference range, even though they will show significant iron staining in hepatocytes. While it is true that iron accumulates in hepatocytes in advanced alcoholic cirrhosis with fibrosis, there are relatively few hepatocytes compared to other inert (fibrotic) tissue, so the quantitative iron determination, which is expressed as mcg of iron per gram of dry weight tissues, yields a low result. Histologic examination of all tissue specimens should be performed to facilitate correct interpretation. When structural heterogeneity is apparent histologically, variation in measured iron should be anticipated. We have observed, in approximately 2% of cases, a high degree of hepatic heterogeneity that makes quantitation highly variable.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories​ ​Monday through Friday ​2 days/3 days if repeat testing required
Dynamic Reaction Cell-Inductively Coupled Plasma-Mass Spectrometry (DRC-ICP-MS)​
Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​83540 ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.