Diagnostic Aids to Qualify and Quantify Iron
Various aids are available to diagnose, manage disease and reach a prognosis for patients with an iron disorder.
Blood & Urine Chemistries Panels:
blood tests can measure basic hormone function, immune function, liver—kidney—bone—heart—pituitary—pancreas—gall bladder— function, mineral levels (iron, copper, zinc, etc); electrolytes, blood cell morphology (size and shape) and performance. Some of these tests are listed on the Iron Disorders Institute Personal Health Profile for Iron Overload form.
are invasive, which means that the procedure involves penetrating an internal organ. This medical procedure is used to determine the extent of organ damage or to confirm disease. Patient with an iron disorder may undergo biopsy of the any vital organ, but the two most frequent biopsies performed on people with too much or too little iron include the liver biopsy and the bone marrow biopsy (also called bone marrow aspiration).
Liver Biopsy Described
The liver biopsy procedure is performed by a surgeon in a hospital setting. A person may be given a general anesthetic or a local anesthetic and a drug to relax them. A needle is used to draw out a specimen of liver tissue to be examined by a pathologist.
The pathologist dries and weighs the specimen, which provides the information needed to calculate the hepatic index. The index is derived from a calculation of the amount of iron concentration (expressed in micromoles of iron per gram of dry liver) in the liver, divided by the age of the patient in years. Hepatic iron greater than 80 mol/g or a hepatic index greater than 1.9 confirms iron overload.
Pathologists can see iron by staining a sample of the tissue obtained from liver biopsy with either Perl’s stain or Prussian blue. The sample is examined under a microscope, where iron appears as dark spots on the pathologist’s slide. Without stain, iron cannot be seen. Staining the tissue sample confirms the presence of iron, whereas drying and weighing the tissue sample, and then analyzing it for iron content, confirms the amount of iron contained in the biopsied organ.
with the availability of the genetic test, the liver biopsy is not longer used to diagnosis hereditary hemochromatosis although liver biopsy remains the gold standard for determining liver damage or disease (cirrhosis, cancer)
Bone marrow aspiration: the procedure is similar to liver biopsy in that a needle is used to penetrate the bone marrow. The needle gathers a small amount of tissue from the marrow, which is stained for iron in the same way as a liver biopsy. Bone marrow tissue reveals the blood cell health and activity. This procedure is performed most often on patients with blood cancers, unexplained iron deficiency anemia or who are preparing for bone marrow transplantation.
Quantitative Phlebotomy is an indirect way of diagnosing hemochromatosis.
In standard phlebotomy, about one pint of blood is removed, which contains approximately
200 to 250 milligrams of iron. In quantitative phlebotomy, the total amount of iron ultimately removed is calculated to determine whether the total body iron load is increased. In general,
4 grams of iron are found in about 16 to 20 pints of blood. Individuals who have 4 grams or more of mobilizable iron by quantitative phlebotomy may be diagnosed with iron overload.
Scans & Imaging
Magnetic Resonance Imaging (MRI):
can qualify and quantify iron in the liver, heart and anterior pituitary, but requires special technique called T2* MRI. This is presently the only non-invasive approach to qualify iron deposits in the heart. FerriScan and SQUID are two aids that use the T2* relaxation approach.
Fibroscan® Noninvasive way to determine the rigidity (hardness) of the liver. A mechanical pulse goes through the skin to the liver. The speed (velocity) with which the pulse moves and reaches its target is measured with ultrasound. The velocity of the pulse is directly correlated to the stiffness of the liver, which in turn reflects the degree of fibrosis. - the stiffer the liver is the greater the degree of fibrosis.
Fibroscan® should not be used on patients with ascites (fluid in the abdomen), patients who are pregnant or patients under the age of 18 years of age. Fibroscan is available mostly in Canada and Europe. For more about the procedure visit: .http://www.fibroscan.co.uk/
FerriScan® is software that allows for a non-invasive (does not puncture the skin) way to measure the amount of iron in the liver (hepatic iron concentrations). The technology works with standard magnetic resonance imaging (MRI) equipment. In a very simplistic description, MRI uses a powerful magnet and radio-frequencies (signals, pulses) which are sent through the person’s body producing a reading that is sent to a computer. Using a specialized technique a trained radiologist can demonstrate differences in the rate at which a signal/pulse transverses (passes through) the body. A reading is taken of these rates (proton transverse relaxation rates, or (R2)) which yield the relaxation time (recovery time) of the signal/pulse. If nothing stands in the way of the signal/pulse, the relaxation time is normal and the output or reading of the organ scanned demonstrates no abnormalities. When the signal is interrupted by a tumor or in this case, iron, the relaxation time is “shortened”. If iron is present in the liver, the output reading shows a “black” area where the signal/pulse recovery time was abbreviated. A radiologist must have additional training to perform this specialized imaging technique.
For more about Ferriscan® visit .http://www.ferriscan.com/
SQUID: Superconducting Quantum Interference Device (SQUID) uses a low-power magnetic field with sensitive detectors that measure the interference of iron within the field. The procedure is expensive, experimental with limited locations in the world providing this technology. Read more about this type of technology
Genetic testing examines DNA for mutations in genes that define a particular disease. This type of test examines DNA from a blood, saliva, or tissue sample for certain mutations. Genetic information does not provide information about iron levels, but it does expose the potential risk of developing iron disorders.