DETERMINING IRON STATUS
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I IRON IN RED BLOOD CELLS
Basic measures
Amount of iron bound to the red blood cells (RBC):
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Hb (haemoglobin) g/100 ml*, g%. Colour reaction measured with absorption spectrophotometer.
(International SI-units: g Hb per liter (g/L))
Amount of red blood cells per unit volume:
- Hcr(PCV) (Haematocrit = Packed Cell Volume) (%), volume of RBC correlated to total volume. Centrifuging.
- RBC - Erythrocytes counted in a diluted, homogenous blood sample. Counter chamber/grid.
Derived values
MCV (Mean Corpuscular Volume)
MCV = PCV/RBC (femtoliter, fl = 10-15 L).
MCH (Mean Corpuscular Hb)
Hb x 10/RBC (picograms, = 10-12 g).
MCHC (Mean Corpuscular Hb Concentration)
MCHC = Hb/PCV (%).
II AMOUNT OF IRON BOUND IN TRANSPORT AND IN STORES
Amount of iron bound in transport:
- S-iron - amount of iron in serum, bound to transferrin.
- TIBC - total iron-binding capacity (an indirect measure of transferrin).
- TfS - transferrin saturation = 100% x serum iron/TIBC.
Amount of iron bound in stores:
-
S-ferritin - correlates with storage iron in healthy individuals (µg/L).
(OBS! S-ferritin is iron-poor (apoferritin))
III OTHER IRON MEASUREMENTS
- FEP - Free Erythrocyte Protoporphyrin (last compound before iron is coupled to Hb).
- TfR - Transferrin Receptor in serum; indicates iron needs of the body cells (mg/L).
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