Ferritin
REF: DS177720 96 tests
Intended use
Immunoassay for the in vitro quantitative determination of ferritin
in human serum.
Summary
Ferritin is a macromolecule with a molecular weight of at least 440
kD (depending on the iron content) and consists of a protein shell
(apoferritin) of 24 subunits and an iron core containing an average
of approx. 2500 Fe3+ ions (in liver and spleen ferritin). (1)
Ferritin tends to form oligomers, and when it is present in excess
in the cells of the storage organs there is a tendency for
condensation to semicrystalline hemosiderin to occur in the
lysosomes. At least 20 isoferritins can be distinguished with the
aid of isoelectric focusing. (2) This microheterogeneity is due to
differences in the contents of the acidic H and weakly basic L
subunits. The basic isoferritins are responsible for the long-term
iron storage function, and are found mainly in the liver, spleen,
and bone marrow. (1, 3) Acidic isoferritins are found mainly in the
myocardium, placenta, and tumor tissue. They have a lower iron
content and presumably function as intermediaries for the transfer
of iron in various syntheses (4, 5, 6) The determination of
ferritin is a suitable method for ascertaining the iron metabolism
situation. Determination of ferritin at the beginning of therapy
provides a representative measure of the body’s iron reserves. A
storage deficiency in the reticulo-endothelial system (RES) can be
detected at a very early stage (7) Clinically, a threshold value of
20 μg/L (ng/mL) has proved useful in the detection of prelatent
iron deficiency. This value provides a reliable indication of
exhaustion of the iron reserves that can be mobilized for
hemoglobin synthesis. Latent iron deficiency is defined as a fall
below the 12 μg/L (ng/mL) ferritin threshold. These two values
necessitate no further laboratory elucidation, even when the blood
picture is still morphologically normal. If the depressed ferritin
level is accompanied by hypochromic, microcytal anemia, then
manifest iron deficiency is present. (1) When the ferritin level is
elevated and the possibility of a distribution disorder can be
ruled out, this is a manifestation of iron overloading in the body.
400 μg/L (ng/mL) ferritin is used as the threshold value.
Elevated ferritin values are also encountered with the following
tumors: acute leukemia, Hodgkin’s disease and carcinoma of the
lung, colon, liver and prostate.
The determination of ferritin has proved to be of value in liver
metastasis. Studies indicate that 76 % of all patients with liver
metastasis have ferritin values above 400 μg/L (ng/mL). Reasons for
the elevated values could be cell necrosis, blocked erythropoiesis
or increased synthesis in tumor tissue. Two monoclonal mouse
antibodies - M-4.184 and M-3.170 - are used to form the sandwich
complex in the assay.
Reagents
Materials provided
• Coated Microplate, 8 x 12 strips, 96 wells, pre-coated with mouse
anti-ferritin.
• Calibrators, 6 vials, 1 ml each, ready to use; Concentrations:
0(A), 20(B), 50(C), 100(D), 300(E) and 600(F) ng/mL.
• Enzyme Conjugate, 1 vial, 11 mL of HRP (horseradish peroxidase)
labeled mouse monoclonal anti-ferritin.
• Substrate, 1 vial, 11ml, ready to use, (tetramethylbenzidine)
TMB.
• Stop Solution, 1 vial, 6.0 ml of 1 mol/l sulfuric acid.
• Wash Solution Concentrate, 1 vial, 25 ml (40X concentrated),
PBS-Tween wash solution.
• IFU, 1 copy.
• Plate Lid: 1 piece.
Materials required (but not provided)
• Microplate reader with 450nm and 620nm wavelength absorbent
capability.
• Microplate washer.
• Incubator.
• Plate shaker.
• Micropipettes and multichannel micropipettes delivering 50μl with
a precision of better than 1.5%.
• Absorbent paper.
• Distilled water.
