On May 11, 2010, in Minerals, Tests, by Andrea

Ferritin is another iron blood test used to determine iron stores.  It is used in conjunction with additional  iron tests to determine overall iron status, as well as supplement efficacy.

Over time, ferritin levels can show how well the body is storing iron, and utilizing that iron.  It is a useful tool, especially when looking at trends.

Ranges given are simply given as a point of reference.  Your lab may use slightly different lab values.  Adapt as necessary.

This is a fasting test.  Mornings are best.

Ferritin is an iron-storage protein that releases the iron in a controlled-fashion.  It acts as a buffer against iron deficiency and overload.  Serum ferritin levels are measured as part of the iron studies workup for anemia and for restless legs syndrome.  Levels have a direct correlation with the total amount of iron stored in the body.  Low ferritin shows a risk for lack of iron, which could lead to anemia; in setting of anemia, serum ferritin is most sensitive lab test for iron deficiency anemia; low levels may also indicate hypothyroidism or vitamin c deficiency.  Low levels (less than 50 ng/mL) have also been correlated with RLS) even in absence of anemia and sickness.  High levels mean too much iron; excess is a marker for iron overload disorders, such as hemochromatosis; can be elevated during periods of acute malnourishment; ferritin concentrations increase drastically in the presence of an infection or cancer.

This is a long-term iron storage protein.  If the body is running low on serum iron levels, it will pull from ferritin to make up the short-fall.  Watch for trends — if your ferritin takes a dramatic dip regardless of your other iron counts changing or staying the same, your body has pulled from the ferritin to make up for a lack of iron in your diet or supplement schedule.  You need more iron.  Ferritin is best made from carbonyl and heme irons.  Ferrous forms are notoriously bad for replenishing ferritin.

Additionally, ferritin is a protein.  If you are not getting enough protein in your diet, you cannot make ferritin.

From Bakermans’s ABC’s of Interpretive Laboratory Data, Fourth Edition:

SPECIMEN: Red top tube, separate serum.
REFERENCE RANGE: Females: 20-200 ng/mL; Males: 20-300 ng/mL; Newborn: 25-200 ng/mL; 1 month: 200-600 ng/mL; 2-5 months: 50-200 ng/mL; 6 months – 15 years: 7 – 142 ng/mL.  Borderline low: 10-20 ng/mL; Iron deficiency: less than 10-12 ng/mL; Iron overload: more than 400 ng/mL.  To convert conventional units in ng/mL to international units in mcg/L, multiply conventional units by 1.00.
INTERPRETATION: The conditions in which serum ferritin measures are of value are given as follows (Skikne BS, Cook JD.  Laboratory Management May 1981; 31-5):

  • Conditions in Which Serum Ferritin Measurements Are of Value
  • Detection of iron deficiency
  • Detection of response and/or endpoint to oral iron therapy
  • Differentiation of anemia of chronic disease from iron deficiency anemia
  • Monitoring iron status of patients with chronic renal disease
  • Detection of iron overload
  • Monitoring the rate of iron accumulation in iron overload
  • Monitoring the response to iron chelation therapy in iron overload
  • Determination of iron status of a population and response to iron fortification
    • Causes of Altered Serum Ferritin
      • Decreased
        • Iron Deficiency
      • Increased
        • Iron Overload: Hemochromatosis, Transfusion Hemosiderosis
        • Gaucher Disease
        • Liver Disease – Acute and Chronic
        • Infection / Inflammation
        • Malignancy

    Iron Deficiency Anemia: One of the first biochemical changes in iron deficiency is a low serum ferritin level; this occurs before iron is decreased and before morphologic abnormalities appear in red blood cells.  Iron deficiency and no other disease is associated with a serum ferritin level less than 10 ng/mL.  At this level, iron stores are essentially depleted.  Serum ferritin level is helpful in differentiating between iron deficiency anemia and anemia of chronic inflammation, infection or chronic disease.  In iron deficiency anemia, serum ferritin is low (below 10 ng/mL).  However, in anemia associated with infection and malignancy, serum ferritin is above 10 ng/mL; a serum ferritin level lower than 50 ng/mL in a patient with obvious inflammatory disease is a strong indicator of iron deficiency.

    In the presence of acute or chronic liver disease, serum ferritin is increased; in iron deficiency anemia plus liver disease, serum ferritin may be normal.

    In patients with iron deficiency anemia who are being treated with iron orally, serum ferritin measurements may be useful in monitoring the response to therapy and in determining the time when iron should be discontinued; a normal hemoglobin does not necessarily indicate that the body iron stores have been replenished. Serum ferritin assays may be done at 3 to 4 week intervals until serum ferritin rises above 50 ng/mL (body iron stores of about 400mg).  Oral iron should be discontinued for a week prior to serum ferritin assay for accurate interpretation.  (Andrea’s note: I disagree in terms of the WLS community as we drop so quickly, as does my Bariatric GI.  This book was written for the general population, of course.)

    In healthy individuals, serum ferritin reflects iron stores: 1.0 ng/mL of serum ferritin is equivalent to 8mg of storage iron.  Total iron stores are 0.7 to 1.5 g.  About 15 to 20 percent of iron is stored within ferritin.

    Serum ferritin may not accurately reflect iron stores in patients on iron supplementation or those with acute or chronic liver disease, infection or inflammation, malignancy, or renal failure.  In these patients, the serum ferritin level may be normal or elevated, even in the absence of stainable bone marrow or iron.

    Characteristics of Ferritin: Ferritin is the main storage molecule for iron.  It is present in highest concentration in the reticuloendothelial cells of the liver and spleen and in the erythroblasts of bone marrow.  It consists of two basic constuents – a protein shell (apoferritin) and a central core of iron in the ferric form existing as a heterogenous ferric oxyhydroxide micelles with some phosphate.

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    3 Responses to “Ferritin”

    1. MacMadame says:

      Okay, I get at least 135 g of protein a day and my protein is still low and my ferritin and iron levels are dropping. I don’t get this as I have no signs of anything that would cause me not to utilize the protein I am ingesting. All my other labs range from acceptable to awesome.

      Is is possible that I’m not getting enough iron and that is causing the low protein count and not the other way around?

    2. MacMadame says:

      Don’t know about copper, but my zinc is 90.

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