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Haematology > Practical > Flashcards

Practical Flashcards

1
Q

what device is used to determine hb?

A

Sahli’s haemoglobinometer

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2
Q

different methods of hb calculation

A

Indirect colorimetric methods
• tallquist’s method - hb is converted into oxyhb
• haldene’s method - hb is converted into deoxyhb
• cyanmeth method - hb is converted into cyanmeth

Direct methods
• Van Slyke’s method for oxygen carrying capacity
• iron estimation
• spectrophotometery

direct all good. of indirect cyanmeth is the best

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3
Q

advantages and disadvantages of sahli’s haemoglobinometer and errors

A

advantages: easy to use, affordable (inexpensive) and fairly accurate

disadvantages : time consuming as the colour has to be matched with the standard
and day time is required

errors :
personal
instrumental : fading of colour strips (standard) in comparator
pipette error : formation of air bubbles while sucking the blood

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4
Q

can we use h2so4 and hno3 instead of hcl

A

no
h2so4 - formation of unstable compound
hno3 - causes precipitation

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5
Q

why glass distilled water and not copper distilled water

A

because cu2+ ions will interfere with colour matching and therefore lead to error.
and tap water because impurities

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6
Q

can u use more or less of n/10 hcl than upto 10 mark. why do you have to wait for 10 minutes?

A

as the instrument is standardised for adding n/10 hcl upto 10 mark and it is also the minimum essential amount required for the formation of acid haematin from 20 mm3 of blood.

most (95%) of haemoglobin is converted to acid haematin within 10 minutes

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7
Q

physiological variations

A
  • age - children > adults
  • sex - men > women
  • diurnal - evening > morning
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8
Q

functions of hb in blood

A
  • transport of o2 from lungs to various tissues
  • transport of co2 from tiisues to lungs
  • maintains the acid base balance by acting as a buffer
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9
Q

stage where hb synthesis starts

A

proerythroblast

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10
Q

calculations of white blood cell count

A

• dilution factor
volume of bulb = 11-1 = 10 (2 drops from stem are discarded)
10 volume of diluted blood contains 0.5 volume of blood.
therefore, 20 volume of blood will contain 1 volume of blood

so, dilution factor = 20

Area of one square = 1 x 1 mm2
Area of four squares= 4 x 1 x 1 mm2

Depth of each square = 1/10 mm
therefore volume of all four squares = 4/10 mm3

let the total number of white blood cells present in all four squares be x

therefore, x = x1+x2+x3+x4

now since 4/10 mm3 volume contains x number of cells,
so 1mm3 of volume will contain = x x 10/4

now after multiplying the dilution factor,

total white blood cells = x x 10/4 x 20
= x x 50 /mm3 of blood

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11
Q

normal wbc

A

4000-11000 /mm3 of blood
above 50,000 - leukemia
below 4000 - leukocytopenia
above 11,000 - leukocytosis

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12
Q

wbc dilating fluid

A

turk’s fluid
• glacial acetic acid - for rbc lysis
• gentian blue / methylene blue - for staining the nucleus of wbcs
• distilled water - for dilution

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13
Q

physiological leucocytosis and leucocytopenia

A
  • in females in menstruation, pregnancy and lactation
  • after severe exercise
  • after cold bath
  • stress
  • diurnal variations - evening > morning low

leucocytopenia
- starvation

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14
Q

pathological - leucocytosis and leucocytopenia

A

leucocytosis -
• acute and chronic infection
• allergic disorders
• leukemia

leucocytopenia
• typhoid fever
• bone marrow depression
• viral or protozoan infection

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15
Q

where are wbcs produced?

A

monocytes + granulocytes - bone marrow

lymphocytes - bone marrow and lymphoid tissues

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16
Q

errors of wbc

A

• pipette errors

  • if pipette is wet hemolysis occurs
  • blood drawn beyond the 0.5 mark
  • less blood drawn due to air bubbles
  • sedimentation of wbcs in the bulb
  • initial drops are not discarded rbc count decreases

• chamber errors

  • air bubble in chamber
  • overflowing of fluid into the trenches therefore wbc count decreases

• field errors

  • uneven distribution of cells
  • not following the L rule and counting along all the four borders of the squares leading to repeated counting
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17
Q

hayem’s fluid

A

Hayem’s fluid:

a. nacl - provides isotonicity
b. na2so4 - anticoagulant
c. hgcl2 - antimicrobial and preservative
d. Distilled water – solvent medium and dilution

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18
Q

what happens to wbc in rbc count

A

the wbcs remain as they are. very less in number so does not interfere in rbc count

19
Q

counting of rbcs

A

• dilution factor
volume of bulb = 101-1 = 100 (2 drops from stem are discarded)
100 volume of diluted blood contains 0.5 volume of blood.
therefore, 200 volume of blood will contain 1 volume of blood

so, dilution factor = 200

Area of one square = 1/5 x 1/5 mm2
Area of five squares= 5 x 1/5 x 1/5 mm2

Depth of each square = 1/10 mm
therefore volume of all five squares = 5/250 mm3

let the total number of red blood cells present in all five squares be N

therefore, N = N1+N2+N3+N4+N5

now since 5/250 mm3 volume contains x number of cells,
so 1mm3 of volume will contain = x x 250/5 = 50x

now after multiplying the dilution factor,

total white blood cells = 50x x 200
= 10000x /mm3 of blood

20
Q

what is anemia

A

anemia is defined as the deficiency of hemoglobin in the blood which can be caused by either too few red blood cells or too little hemoglobin in the cells.

21
Q

pathological variation anemia polycythemia

A

anemia

  • Pernicious Anemia
  • aplastic anemia
  • iron deficiency
polycythaemia
- primary - polycythemia vera (cancerous production of rbcs)
- secondary polycythemia 
• chronic respiratory diseases
• congenital heart disease
22
Q

what is the imp of keeping a control in the blood group experiment

A
  • to compare and to look for the presence or absence of agglutination
  • also helps to rule out pseudo agglutination
23
Q

what prevents the coagulation of blood in this experiment

A

sodium citrate in saline prevents the coagulation

24
Q

mechanism of hemostasis

A
  • vascular spasm
  • platelet plug formation
  • blood coagulation
  • clot retraction
25
Q

bleeding time prolonged in

A

idiopathic thrombocytopenic purpura

26
Q

clotting time is prolonged in

A

classical hemophilia and Christmas disease, vitamin k deficiency and liver diseases - hepatitis, cirrhosis

27
Q

why clotting time more than bleeding time

A

because clotting time is a biochemical process wherein there is an interaction between various clotting factors and this requires more time than a mechanical process like vascular spasm

28
Q

different laboratory anticoagulants

A

• edta (Ethylenediamine tetra acetic Acid)
• oxalates and citrates
combine with ca2+ and decreases theur concentration and therefore prevents process of coagulation

• heparin inhibits thrombin formation.

29
Q

platelet count is increased and decreased in (pathologically)

A 
inc
• trauma
• infections 
• bone marrow malignancy 
• splenectomy
• iron deficiency anemia 
dec
• idiopathic thrombocytopenic purpura 
• infections (like dengue)
• splenomegaly
• aplastic anemia
30
Q

functions of platelets

A
  • vascular spasm
  • platelet plug formation
  • blood coagulation
  • stabilizing the clot
  • clot retraction
  • mild phagocytosis
  • repair of ruptured blood vessel (PDGF)
31
Q

thrombocytopenic purpura

A

clinical condition in which there is a decrease in platelet count below 50,000 per mm3 characterized by multiple subcutaneous hemorrhage and prolonged bleeding and clotting retraction time

32
Q

clinical significance of reticulocyte

A

to see observe the effect of hematinic drugs on erythropoiesis during recovery from anemia

normal : adult and Children - 0.2 -2%
infant and cord blood - 2-6%

33
Q

wintrobe and westergrens normal values

A

males :

wintrobe - 0-9mm at the end of 1st hour
westergrens - 3-5 mm at the end of 1st hour

females

wintrobe - 0-20 mm
westergrens - 5-7 mm

34
Q

wintrobes tube advantage

A

quantity of blood needed is small

same can be used for pcv

35
Q

normal values of pcv

A
  • males - 40-47

- females - 37% to 45%

36
Q

pcv

A

height of rbc coloumn/ total height of blood coloumn x 100

37
Q

mcv mch mchc

A

mcv - average volume of a red blood cell

  • pcv/red cell count x 10
  • 78-94 umm3

mch - represents average weight of hemoglobin in one red cell

  • hb gm% / rbc count x 10
  • 27-32 pg

mchc - represents the amount of hb per 100 ml of red cells

  • hb gm % / pcv x 100
  • 32-38%
38
Q

normal fragility

A

0.46-0.34 % of nacl

39
Q

osmotic fragility imp

A
  • no direct clinical significance but additional investigation to detect intrinsic defects of rbcs in diff types of anemia like hemolytic anemia, sickle cell anemia and hereditary spherocytosis
40
Q

fragility is altered in

A 
increased - 
venous blood
stored blood
hereditary or acquired spherocytosis
sickle cell anemia

decreased -
thalassemia
iron deficiency anemia

41
Q

due to mismatching

A

acute or first degree - chills, rigor, fever, pain in loin
second degree - hemolysis or jaundice
delayed third degree - acute renal shutdown.

42
Q

spirometry

A

fev fev1 fev2 - obstructive jaundice dec

fev1 and fev2 normal and vc is decreased

43
Q

dyspnoeic index

A

mvv - rmv / mvv x 100

normal - 90 and reduced below 60-70

44
Q

hb normal values

A

men - 15 -17 gm /100 ml.
In Females:13 - 14.5 gm/100ml.
newborn:23 gm/100ml. of blood

Haematology (10 decks)

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