Lab 5: evaluation of RBCs, anaemias Flashcards
normal Hgb range?
18-20 mmol/l
12-18g/dl (g%)
how to measure for haemoglobin?
- spectrophotometric method (Drabkin method)
- rough estimation:
- PCV/3 X 1000
oxygen binding capacity of Hgb is increased by?
- reduced 2,3 DPG level in RBCs
- Reduced pCO2 pressure in the blood (e.g. respiratory alkalosis)
- increased blood PH (metabolic or respiratory alkalosis)
- decreased blood temperature ( Hypothermia)
oxygen binding capacity of Hgb is reduced by?
- decreased 2,3 DPG concentration in RBCs
- increases pCO2 pressure in the blood (respiratory acidosis)
- decreased blood PH (metabolic or respiratory acidosis)
- increased blood temperature (hyperthermia)
oxygen saturation of arterial and venous blood?
- Arterial = 95-100%
- venous = 80-90%
what is methaemoglobin?
- Hgb molecules containing Fe of 3+ form
- cannot carry oxygen
- increase in concentration in the blood in the case of severe oxidative damage to RBCs (paracetamol, onions, free radicals)
- in this case the blood is chocolate brown
causes of increased Hgb concentration?
- usually associated with relative (dehydration) or absolute
polycythaemia
causes of decreased Hgb?
- usually associated with relative (hyperhydration) or absolute oligocytaemia
- Decreased RBC count
- Piglets have very low concentrations of Hgb
measuring techniques for RBCs?
- Burker chamber method
- Estimated RBC count
- Ht/5 x100 = RBC x10-12
- RBC count using automatic cell counter
- electronic impedance method
Derivative RBC parameters?
- MCH
- MCV
- MCHC
- RDW
what is needed to calculate RBC parameters?
- Ht or PCV
- RBC count
- Hgb concentration
the equation for calculating MCH?
Hgb (g/l)/RBC count = MCH (pg)
the equation for mean corpuscular volume?
PCV/RBC count x1000 = MCV (fl)
normal range of MCH?
- 20-30 pg
some causes of microcytosis?
- chronic blood loss
- iron, copper, pyridoxine deficiency
- portosystemic shunt
some causes of macrocytosis?
- polycythaemia absoluta vera (erythroleukaemia)
- vit. B12, folic acid, cobalt deficiencies
- erythroleukaemias
the equation for MCHC?
Hgb/PCV = MCH/MCV x1000 = MCHC
MCHC normal range?
30-35%
causes of decreased MCHC (hypochromasia)
- newborn animals
- regenerative anaemias
- iron deficiency anaemia
causes for increases MCHC (hyperchromasia)
- Erythroleukaemias
- vit B12, folic acid, cobalt deficiencies
- immunehaemolytic anaemia
- lead poisoning
- splenectomy
give the key features or reticulocyctes?
- immature RBCs
- not nucleated
- able to carry oxygen
- appearance in the bloodstream is a sign of regenerative function of the bone marrow
normal reticulocyle count?
normally: 2-3% of RBCs
causes for increased reticulocyte count?
- can be caused by different types of regenerative anaemias:
- acute blood loss
- Heamolytic anaemia
- chronic blood loss
- some types of nutrient deficient anaemias
Osmotic resistance of RBCs is dependant on?
- PH pf the plasma (usually 7.4) and reagents
- temperature
- osmotic concentration of plasma and reagents
- RBC membrane status
- Regenerative status (reticulocytes more resistant)
- HbF (fetal haemoglobin) content of RBCs (more resistant)
methods for measuring the osmotic resistance of RBCs?
- make a dilution line from NaCl soloution from 0.3 - 2.5%
- check for haemolysis
- prepare a hypotonic solution from NaCl
- check for haemolysis
list the proper staining methods for RBCs?
- Mar-grunwald staining
- Giesma staining
- Diff quick staining
list the inclusion bodies?
- Heinz body
- denatured Hgb
- Howell-jolly body
- nuclear membrane remnants
- Basophilic punctuates
- nuclear remnants
- Hgb inclusions
list some RBC parasites?
- Babesia spp.
- erlichia canis, Equi etc
- Dirofilaria immitis repens
- Anaplasia marginale
- trypansosma evans
what is the normal blood iron range?
-18-20micromol/l
how is iron reduced?
- from unabsorbable Fe 3+ to absorbable Fe2+ by ascorbic acid in the duodenum
causes of decreased iron concentration?
- reduced intake (calves, piglets)
- chronic bleeding
- impaired gastric, duodenal, jejunal function (reduced reduction, transport, absorption)
causes of high iron concentration?
- iron overdose (iron toxicosis)
what is TIBC?
serum iron level (saturated transferrin) + free transferrin (unsaturated)
causes of low TIBC?
- chronic inflammation
- chronic liver failure
- neoplastic disease
causes of high TIBC
- iron deficiency anaemia
laboratory findings of haemolysis?
- PCV reduced
- Polychromasia, polikilocytosis
- leucocytosis
- spherocytosis
- total biliruben increased
- indirect biliruben increased
- lactate dehydrogenase (LDH) I, II increase
- haptoglobin decrease
- RBC osmotic resistance decrease
- Jaundice
- Hyperchromatic stool - higher than normal amount of haemoglobin
- increased urobilinogen and Hgb in the urine
