Choice and assessment of clinical laboratory parameters in iron deficiency anemias.
Anemia
- Normocytic, normochromic – MCV, MCH in ref ranges
- Hypocytic, hypochromic – ↓MCV, ↓MCH, Fe deficiency, thalassemia’s
- Macrocytic - ↑MCV, ↑MCH
- Megablastic – B12 and folic acid deficiency
Size (microcytic/normocytic/macrocytic) Hb (hypochromic/normochromic/hyperchromic)
Normal ranges Haemoglobin: m140-180, f: 120-160 g/L Hematocrit: m: 0.4-0.54, f: 0.36-0.47 l/L Erythrocytes m: 4.5-6.0, f: 3.9- 5.4 T/L MCV (volume of 1 RBC) 82-96 fl MCH (content of haemoglobin in 1RBC) 27-33 pg MCHC (content of haemoglobin in all RBC)300-360 g/L
Anaemia also may be classified by red cell morphology as macrocytic, normocytic, or microcytic, an approach that is useful in differential diagnosis. MCV – microcytic anemia (< 75 fl) MCV – macrocytic anemia (>105 fl)
Basic analyses: CBC (Hb, Erys number, Hct, MCV, MCH, MCHC, RDW, Thr, WBC); screening coagulation tests (PT, APTT, FBG, TT), urine, morphology of RBC (peripheral blood smear), Ret
Iron deficiency 3 types 1) Functional ion in haemoglobin 2)Ferritin - Storage iron in tissues (Male: 40-200ug/L, Female:30-100ug/L) 3) Transferrin – protein that carries iron in our organism. Transferrin ↑, Fe ↓
1st phase – Pre latent, concentration of ferritin ↓ 20-30ug/L 2nd phase – Latent, Fe ↓, Transferrin ↑, 3rd phase - ↓ RBC, Hb, Hct ↓ MCV, MCH ↓↓ Fe, ↓↓Ferritin ↑ Transferrin
Iron status determined by the amount of circulating iron in the blood, the capacity of the blood to transport iron, and the amount of stored iron in tissues.
- Testing helps differentiate various causes of anemia and may include: Serum iron measures the level of iron in the blood.
- TIBC (total iron-binding capacity) measures all of the proteins in the blood that are available to bind with iron, including transferrin. the TIBC test is a good indirect measurement of transferring.When iron stores are low, transferrin levels increase and vice versa.
- Zinc Protoporphyrin (ZPP). Protoporphyrin is the precursor to the part of hemoglobin (heme) that contains iron. The amount of zinc protoporphyrin in red cells is increased in iron deficiency. ZPP is sometimes used as a screening test.However, the test is not specific for iron deficiency, thus elevated values must be confirmed by other tests.
- HFE gene test. Hemochromatosis is a genetic disease, that causes the body to absorb too much iron. It is usually due to an inherited abnormality in a specific gene, called the HFE gene .The HFE gene test determines whether a person has the mutations that cause the disease.