5. Red Blood Cells Flashcards
What can problems with RBC´s cause?
Hypoxia (deficiency of O2 reaching tissues)
Most important parameters for RBC´s?
What can they evaluate?
RBC count, haemoglobin conc. and/or function.
Evaluate polycythemias caused by diff. ext/int causative agent.
Spectrophotometric Method (Drabkin-method)
- Colour of end product?
- Wave length?
- Calculation?
- What is the measured Hgb conc?
- Which carrier molecule is the Hgb usually bound to?
- What happens with Hgb during intravascular hemolysis?
- Orange
- 540 nm
- (Esample/Estandard) x standard conc. = result
(E=extinction) - The measured Hgb conc is a sum of Hgb molecules from the haemolysed RBCs and the small amount of free Hgb content of plasma
- A carrier protein: haptoglobin
- There is no notable increase in Hgb conc in case of intravascular haemolysis
Oxigen binding capacity of Hgb is ↑ increased by
- decreased ↓ 2,3 DPG level in RBCs,
- decreased ↓ pCO2 level in the blood
- increased ↑ pH of the blood
- decreased ↓ temperature of blood
Oxygen binding capacity of Hgb is ↓ decreased by
- increased ↑ 2,3 DPG level in RBCs,
- increased ↑ pCO2 level in the blood
- decreased ↓ pH of the blood
- increased ↑ temperature of blood
Oxygen saturation (SAT %)
- Definition
- Normal values
- The percentage of oxygenated Hgb molecules compared to the whole amount of Hgb molecules in one unit of blood.
- Arterial blood: 95-99 %, Venous blood: 80-90 %
- What function does Fe´2+ have in Hgb molecules?
- What function does Fe´3+ have in Hgb molecules?
- Which enzyme reduces Fe3+ to Fe2+
- Fe2+:able to take up oxygen molecules in the lungs, carry them, and deliver them to the cells, where they are used in the terminal oxidation phase of the
metabolic process. - Fe3+: Called methaemoglobin. Unable to carry oxygen. 3. Methaemoglobin-reductase enzyme: reduces methhaemoglobin to normal hemoglobin.
- Examples of severe oxidatives
- What is methaemoglobinaemia?
- Which species are sensitive to oxidative damage?
- Nitrites, free radicals, paracetamol, onion.
- Incr methaemoglobin level in the blood. The colour of the blood is dark brown and the mucous membranes are deeply cyanotic.
- Cats and newborn or very young animals of any other species
Rough estimation of Hgb concentration
PCV (l/l)/3 *1000=Hgb (g/l)
Causes of increased ↑ Hgb concentration
- ususally associated with different types of relative dehydration
- absolute polycytaemia
Causes of decreased ↓ Hgb concentration
- ususally associated with relative hyperhydration
- absolute oligocytaemia (anaemia)
Which animals have Hgb conc. which is affected by the age?
Swine: young pigs have much lower Hgb conc, than older ones.
Estimated RBC-count
If we suspect a normal average RBC volume:
(Ht l/l / 5) x 100 = RBC count x 10^12/l
Counting red blood cells is based upon?
What size has RBC´s to be?
- The electric impendance of the particles. Impedance is in correlation with the size.
- 40-100 fl
Normal RBC count
4.5-8 x 10^12/lT/l
- In order to calculate the indices, what do we have to measure?
- Who can use this indices?
- Ht or PCV (hematocrit, packed cell volume), red blood cell count, haemoglobin concentration (Hb).
- Humans, dogs and maybe cats. In case of horses, ruminants these are almost useless because of the big variance among parameters of RBCs of different animal individuals, and also within individuals
Mean Corpuscular Haemoglobin (MCH)
- What does it indicate?
- Calculation?
- Normal value?
- Decreased ↓ MCH
- Increased ↑ MCH
- Average Hb content of RBCs
- Hgb (g/l) / RBC count x 10^12/l = MCH (pg)
- 12-30 pg. In young animals it (and MCV) can be incr to 28-32 pg
- hypochromasia
- hyperchromasia
MCH
- Horse
- Ruminants
- Dog
- Cat
- Horse 12-20
- Ruminants 8-17
- Dog 15-24
- Cat 13-17
(pg)
Mean Corpuscular Volume (MCV)
- What does it indicate?
- Calculation?
- Normal value?
- MCV indicates the average size of the RBCs
- PCV / (RBC count x 1000) = MCV (fl)
- 60-70 fl
MCV
- Horse
- Ruminants
- Dog
- Cat
- Horse 37-58
- Ruminants 42-52
- Dog 63-75
- Cat 40-53
(fl)
- Which species have smaller RBC´s?
2. Which species have bigger RBC´s?
- Cats, horses have smaller RBCs. Adult animals. Japanese Aktia.
- Young RBCs are bigger. New borns. Some poodles.
Some causes of microcytosis
- chronic blood loss
- iron, copper, pyridoxine (vitamine B6) deficieny
- portosystemic shunt
Some causes of macrocytosis
(mostly regenerative anaemias)
polycythaemia absoluta vera (erythroleukemia)
vitamin B12, folic acid, cobalt deficiency
erythroleukaemias
Mean Corpuscular Haemoglobin Concentration (MCHC)
- What does it indicate?
- Calculation?
- Normal?
- the average conc of haemoglobin in erythrocytes
- Hgb (g/l) / PCV = MCH (pg) / (MCV (fl) x 1000) = MCHC (g/l)
- 300-350 g/l (30-35%) - normochrom
MCHC
- Horse
- Ruminants
- Dog
- Cat
- Horse 31-37
- Ruminants 30-36
- Dog 32-36
- Cat 30-36
(%)
Decreased MCHC - hypochromasia
newborn animals
regenerative anaemias
iron deficiency anaemia
Increased MCHC - hyperchromasia
erythroleukemia (polycythaemia absoluta vera)
vitamin B12, folic acid, cobalt deficiency
immunhemolytic anaemia (spherocytosis)
lead poisoning
splenectomy
Typical changes in derivated parameters
1. macrocytic, hypohromic: MCV incr, MCHC decr
(Reticulocytes incr)
2. normocytic, normochromic: MCV same , MCHC same
normal or decr MCH
3. microcytic, hypochromic: MCV decr , MCHC decr
(decr Hb synthesis)
4. microcytic, normochromic: MCV decr , MCHC same
5. macrocytic, normochromic: MCV incr , MCHC same,
impaired DNA synthesis
- regenerative anaemias
- non regenerative anaemias
- iron, copper, piridoxine, deficiency anaemias, liver, failure, portosystemic shunt
- Japanese Akita (normal)
- FeLV infection, vitamin B12, Co, or folic acid deficiency, erythroleukemia, poodle macrocytosis
Reticulocyte count
- Describe reticulocytes
- rRNA remnants
- Which reticulocytes are younger?
- Which species does not have reticulocytes?
- What is appearance of reticulocytes a sign of?
- Which reticulocytes can carry oxygen?
- Young, but differenciated RBCs, with basophil punctates stained by Brylliant-cresil blue stain
- Blue punctates in the reticulocytes
- Reticulocytes containing big blue aggregates (aggregated forms), are younger, than those containing small punctates (punctated forms).
- Horses and ruminants.
- The regenerative function of bone marrow
- Reticulocytes have the same functional properties as mature RBCs, so they are able to carry oxygen. Nucleated RBCs are too young, therefore they are not able to function as RBCs/carry oxygen
Corrected reticulocyte count (CRC)
- Calculation
- Normal values?
- CRC = reticulocyte % x RBC count
2. <0,06 x 1012/l (without anaemia!)
Corrected reticulocyte percentage (CRP)
- Calculation
- Normal values?
CRP = (Htpatient / Htaverage ) x reticulocyte %
(Htavg: 0,45 dog, 0,37 cat)
<1-2 % (without anaemia!)
What can increased reticulocyte count be caused by?
Different types of regenerative anaemias: acute
blood loss, haemolytic anaemia, chronic blood loss, some types of nutrient deficiency anaemias.
How many days are needed for the bone marrow to increase the reticulocyte count in the blood?
approx. 3-5 days
Osmotic resistance of RBC is dependent on?
The pH of the plasma, and the reagents, the temperature, the osmotic conc of plasma and the reagents and the RBC membrane status, the regenerative status, the HbF content of the RBCs
Size of RBCs:
- Macrocytosis
- Microcytosis
- Anisocytosis
- Poikylocytosis
- Macrocytosis: many big cells
- Microcytosis: many small cells
- Anisocytosis - variable cell size - iron deficiency and regenerative process
- Poikylocytosis: variable size and colour
Young and nucleated RBCs (in order of maturation)
- Proerythroblast
- Basophil erythroblast (normocyte, normoblast)
- Polychromatophil erythroblast (normocyte, normoblast)
- Acidophil erythroblast (normocyte, normoblast)
Young but mature RBC without nucleus
reticulocyte
Appearance of young RBCs
Incr prod (regenerative anaemia), spleen or bone marrow disease, leukaemia, extramedullar erythrocyte production, Pb toxicosis, hyperadrenocorticism
Reticulocyte appearance
increased production (regenerative anaemia) - chronic Fe deficicency anaemia, haemolysis, acute blood loss, chronic blood loss !
Spherocyte appearance
(spherical small polychromatophil RBC)
sensitive RBC membrane, immunemediated hemolysis
Stomatocyte appearance
(mouth-shaped RBC)
incr RBC production (regenerative anaemia)
Acanthocyte appearance
(Spur cell - RBC with few long spikes)
RBC membrane failure (lipid bilayer) – lipid metabolism disorder, hepatopathies
Schysocyte appearance
(RBC fragment)
traumatic or toxic damage (uremia, blood parasites, long term severe physical activity, DIC)
Anulocyte appearance
(0 - like RBC)
iron deficiency anaemia
Codocyte appearance
(Target cell, like a target)
regenerative process
Echynocyte appearance
(Burr cell, crenation, RBC with many small spikes): laboratory error (too quick drying of blood film, uremia, DIC)
Sickle cell appearance
RBC damage, Hb globin chain malformation in humans
Inclusion bodies in RBCs and their appearance
- Heinz body: denaturated Hgb
- appearance: O2 effect, oxidative damage to RBCs, GSH deficiency - Howell-Jolly body : nuclear membrane remnants
- appearance: vit B12 deficiency, incr prod of red cells, splenectomy - Basophilic punctuates: nuclear remnants
- appearance: regenerative process, young RBCs of cat, physiological in ruminants, lead poisoning - Hb inclusions
- appearance: Hb damage, increased RBC production, regenerative anaemia
RBC parasites
- Haemobartonella canis, felis, bovis
- Babesia spp. (canis, gibsoni)
- Ehrlichia canis, equi etc.
- Dirofilaria immitis, repens
- Anaplasma marginale, centrale, ovis,
- Eperythrozoon wenyoni, ovis, suis, parvum
- Citauxzoon felis
- Theileria parva, mutans, annulata, hirci, ovis
- Trypanosoma cruzi, congolense, vivax, brucei, evans, suis, equiperdum
- Leishmania donovani
When do we use Serum iron measurement?
-Normal SeFe (serum iron)
If we suspect iron deficiency, especially due to chronic blood loss.
-18-20 mmol/l
Causes of low serum iron concentration
chronic blood loss
decreased intake (piglets, calves)
impaired gastric, duodenal, jejunal function (reduction, transport, absorption)
Causes of high serum iron concentration
iron toxicosis (overload)
When do we use total iron binding capacity (TIBC)?
-TIBC (total iron binding capacity)
It gives information about the transferrin content.
50-68 mmol/l
Causes low TIBC
chronic inflammation (neg acute phase protein)
chronic liver failure (decr transferring synt in liver)
neoplastic disease
Causes of high TIBC
iron deficiency anaemia (not severe: normal iron level+high TIBC, severe: low iron level+high TIBC)
Iron Saturation:
- Calculation
- Normal values?
- (SeFe / TIBC) x 100 = Iron saturation
2. normal: 20-55% (30%)
Laboratory Findings in Hemolysis
- PCV decr,
- reticulocytes incr (renerative anaemia)
- polychromasia, poikilocytosis
- leukocytosis, (neutrophilia)
- spherocytosis,
- total bilirubin incr
- indirect bilirubin incr
- lactate dehydrogenase (LDH) I,II incr
- haptoglobin decr
- RBC osmotic resistance incr
- jaundice
- hyperchromic stool,
- urobilinogen and Hgb in urine incr