52) CHOICE AND ASSESSMENT OF CLINICAL LABORATORY PARAMETERS IN HEMOLYTIC ANEMIAS.
When speaking about erythrocytes, we look at
- Size 6-9um with diameter of 2um
- Colour - when correct colour, it is called normochromic (pale central colour)
- Shape – circular with pale central area
- Erythrocyte inclusions – when correct cell content it is called normocyte
Megalocytes - no central paler area Target cells – one central point of haemoglobin in central paler area.
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
Pathophysiological
- (1) Disturbance
- Aplastic/hypoplastic anaemia
- Erythropeotin sensitive stem cell
- DNA synthesis – B12, folic acid
- Synthesis of haemoglobin iron deficiency
- Kidney disease. Synthesis of erythropoeietin
- (2) Haemolytic anaemia – hereditary/acquired
- (3) Loss of blood – haemorrhage→can lead to shock if more than 20% of blood volume lost will lead to hypovolemic shock.
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
- Hemolytic anemias is due to problems that cause the red blood cells (RBCs) to die or be destroyed prematurely. Normally, RBCs live in the blood for about four months. In hemolytic anemia, this time is shortened, sometimes to only a few days. The bone marrow is not able to produce new RBCs quickly enough to replace those that have been destroyed, leading to a decreased number of RBCs in the blood
Inherited Hemolytic Anemia
Two of the most common causes of inherited hemolytic anemia are sickle cell anemia and thalassemia: Laboratory Tests:Since some of these inherited forms may have mild symptoms, they may first be detected on a routine complete blood count (CBC) and blood smear, which can reveal various abnormal results that give clues as to the cause.