zaterdag 29 oktober 2011

Introduction to iron and serum ferritin tests

Introduction to iron and serum ferritin tests



Iron is fundamentally required by the body to form adequate numbers of normal red blood cells. These are the cells that carry oxygen throughout the body. The key protein in red blood cells to which oxygen attaches is called hemoglobin (haemoglobin in Europe). Hemoglobin is a very iron rich biochemical. Iron is also needed by other cells, especially muscle cells which contain another oxygen binding protein called myoglobin. Typically in the healthy individual, about 65% of the iron in the body is in hemoglobin (in red blood cells) and about 4% in myoglobin (in skeletal muscle). About 30% of the iron in the body is stored (as ferritin or hemosiderin) in liver, bone marrow, and the spleen. A small percentage of the body's iron is in transport between various compartments of the body (in association with transferrin) or is a component of enzymes in cells throughout the body. Free iron is very reactive (it stimulates free radical reactions) and is not normally in body fluids. Low iron levels can lead to anemia, in which the body cannot produce enough red blood cells. This results in a poor ability to transfer oxygen around the body and the symptoms are chronic lethargy (tiredness) and a very pale skin pallor. So for the body in general, iron is very important.
However, there is a lot of argument among professionals as to whether iron is important for hair growth. Some say it is vital and that deficiencies in serum iron and ferritin, the biochemical state in which iron is stored in the body, can have a dramatically negative impact on hair growth. The predominant belief among most general practitioners is that iron deficiency should not be a significant cause of hair loss. Some dermatologists agree. However, there are now several scientific studies and a growing number of dermatologists claiming that iron deficiency is relatively common. Even with a Western diet it is suggested that chronic iron deficiency is common and can lead to a gradual development of diffuse hair loss - a kind of telogen effluvium. It is believed that as people have reduced their rate of red meat intake, a rich source of iron, and switched to white meats or vegetarianism, so iron deficiency has become more common.


Iron and serum ferritin test result normal ranges table
Factor tested
Normal range for test value

Adult men
Adult women
Serum Iron (micro grams per deciliter)
60 - 160 µg/dL
60 - 160 µg/dL
Total Iron Binding Capacity (TIBC) (micrograms per deciliter)
240 to 450 µg/dL
240 to 450 µg/dL
Serum Ferritin (micro grams per liter)
20-300 µg/L (official value stated by non-dermatologists)
OR
70-300 µg/L (claimed by dermatologists who believe iron deficiency causes hair loss)
18-200 µg/L (official value stated by non-dermatologists)
OR
70-200 µg/L (claimed by dermatologists who believe iron deficiency causes hair loss)
Hemoglobin (grams per deciliter)
13.0 –18.0 g/dL
12.0 - 16.0 g/dL
Mean Corpuscular Hemoglobin (MCH) (pico grams per cell)
27 - 35 pg/cell
27 - 35 pg/cell
Mean Corpuscular Hemoglobin Concentration (MCHC) (grams per deciliter)
32 - 37 g/dL
32 - 37 g/dL
Mean Corpuscular Volume (MCV) (cubic micrometers)
78 - 100 cu µm
78 - 102 cu µm
Red Blood Cell Count (RBC) (millions per microliter)
4.2 - 6.9 million/µL (normal range varies with age)
4.2 - 6.9 million/µL (normal range varies with age)
Transferrin (milligrams per deciliter)
191 –365 mg/dL
191 –365 mg/dL
Transferrin saturation (percentage)
20-50%
20-50%


An explanation of iron and serum ferritin tests
There are actually several aspects of the iron metabolic pathway that can be tested. In terms of hair loss the most useful test value is believed to be the serum ferritin level. However, testing other iron parameters can be helpful in understanding the general health of patients.
Serum iron level - Serum iron is a measure of circulating iron bound to transferrin and reflects total body iron. Serum iron measurements may be affected by menstrual cycle, time of day, diet, hepatitis, and use of iron containing placebos found in some oral contraceptive packages. On its own this test just gives a snap shot in time of your iron levels and it is not very helpful for defining a chronic iron deficiency or other iron problems. However, when the test value is examined in comparison to other iron tests it can help provide information leading to a disease diagnosis.
Serum ferritin level - Ferritin is an indicator of stored iron in the body. Ferritin is the main protein that stores iron for areas that need it, especially the liver and the bone marrow where red blood cells are made. The iron ferritin level is the first in line to drop if the individual suffers any iron insufficiency from diet, malabsorption or loss during heavy or menstruation lasting more than 5 days. A drop in the iron ferritin level occurs before any depletion in serum iron (as seen in iron-deficient anemia) and may decrease significantly without any obvious symptoms whatsoever. While the serum ferritin level at which a deficiency can be claimed is hotly argued by different schools of doctors, an excess of serum ferritin is generally agreed to be a bad thing. Iron stored at high levels is toxic. The body can only metabolize so much iron in a day. If it receives too much, the body is overwhelmed and toxic effects develop. It is possible to overdose on iron supplements. For this reason, taking large supplement doses of iron is not recommended. If, in response to a low iron and ferritin test result, you start to take iron supplements and feel ill, it probably means you are taking to much for your body to cope with. Take a lower dose.
Total Iron Binding Capacity (TIBC) - TIBC measures the amount of transferrin you have. Transferrin is a blood protein that transports iron from the gut, where the iron is absorbed from food, to the cells that use it. When iron stores are low, the body will make more transferrin so that it can collect more iron absorbed from food and make more efficient use of it. If there is too much iron coming from the gut, the body will reduce production of transferrin so that less of the iron is taken up and transported around the body. On average about one third of the transferrin in the body is being used to transport iron. Because of this, the blood serum of healthy individuals has an excess iron-binding capacity. This is called the Unsaturated Iron Biding Capacity (UIBC). The TIBC equals UIBC plus the serum iron measurement. Some laboratories measure UIBC, some measure TIBC, and some measure transferrin. These tests are usually done together and analyzed in relation to each other. On their own the values do not mean much, but together the test results are helpful in defining several iron problems.
Hemoglobin and Hematocrit – Hemoglobin and hematocrit levels are tested when anemia is suspected. Serum hemoglobin is a test that measures the level of free (outside red blood cells) hemoglobin in the blood while hematocrit is the measurement of the percentage of red blood cells in whole blood. It is an important determinant of anemia (decreased), dehydration (elevated) or possible overhydration (decreased). These tests can be useful for understanding iron metabolism in the body as one cause of anemia is iron deficiency. These tests are usually conducted in conjunction with a complete blood cell count (CBC) looking at numbers of while blood cells (see the blood cell count test page in this section). Of these other test values the Mean (average) Corpuscular Volume (MCV) can also indirectly help understand iron metabolism as MCV measures how big the red blood cells are. Corpuscule is just a fancy word for cell. When a deficiency in iron occurs, not enough hemoglobin is made. This leads to a somewhat reduced rate of red blood cell production and the red blood cells are often smaller than normal (microcytic) and paler than normal (hypochromic).


An explanation of what iron and serum ferritin test results mean for hair loss
Iron, UIBC, TIBC and ferritin test results are often looked at from the global perspective. A change in one test value exerts an influence on one or more of the other test values. Depending on how these different test values deviate from the norm and each other, an iron problem can be diagnosed. Classic iron deficiency due to a lack of iron intake results in a test result pattern where the serum iron level and serum ferritin level is low while the TIBC and UIBC levels are high. If this is observed, and the claim that iron deficiency causes telogen effluvium hair loss is believed, then iron supplements or an iron rich diet may help.
Other test result patterns can suggest other problems that may affect hair growth in a different way. If the serum iron and TIBC levels are low While UIBC is low to normal and ferritin levels are normal to high, the pattern is consistent with a chronic illness. Chronic illness may itself cause hair loss through a general reduction in nutrients and sometimes hormonal stimulation for hair follicles. A diffuse telogen effluvium hair loss can be the result.
Telogen effluvium can also develop after exposure to toxins and iron in excessive amounts is toxic. A test result pattern where the serum iron and and ferritin levels are excessively high, but the TIBC and UIBC are low suggests an excessive intake of iron. There is also a genetic condition called hemochromatosis where the affected individual cannot process iron properly and even with low iron intake the iron can build up in the body to toxic levels. In affected individuals the pattern of iron tests results show a high serum iron level, but normal levels for ferritin and TIBC and low to normal levels for UIBC. Where hemochromatosis is suspected and genetic test should be conducted to if the individual carries a certain gene mutation (below).


Testing for hemochromatosis
Hemochromatosis is relatively common in Northern Europe and descendants of Europeans in the Americas. It has an official expression frequency at approximately 6 in 100,000 people although some doctors believe the condition is under diagnosed and the frequency of expression could be as high as 1 in 200. It is caused by a mutation in a gene called "HFE". The most common mutation is called C282Y but there are other rarer mutations as well. The HFE gene regulates the amount of iron absorbed from the gut. In people who have two copies of an abnormal form of the gene, the protein made by the gene cannot tell the cells in the gut when the body is “full” of iron, so the gut keeps on absorbing iron and excess iron damages many different organs. If a blood iron test suggests hemochromatosis may be a problem then another blood sample may be drawn and subjected to the HFE gene test. People with hemochromatosis may suffer from chronic telogen effluvium - although there are usually other associated clinical symptoms of iron poisoning.
In February 1997, a panel of medical experts convened by the CDC recommended that transferrin saturation (TS) be used as the initial diagnostic test for hereditary hemochromatosis. A value above 50% indicates a potential hemochromatosis diagnosis and further tests should be done.

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