Practical

Question 1

what device is used to determine hb?

Answer 1

Sahli’s haemoglobinometer

Question 2

different methods of hb calculation

Answer 2

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

Question 3

advantages and disadvantages of sahli’s haemoglobinometer and errors

Answer 3

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

Question 4

can we use h2so4 and hno3 instead of hcl

Answer 4

no
h2so4 - formation of unstable compound
hno3 - causes precipitation

Question 5

why glass distilled water and not copper distilled water

Answer 5

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

Question 6

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

Answer 6

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

Question 7

physiological variations

Answer 7

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

Question 8

functions of hb in blood

Answer 8

• 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

Question 9

stage where hb synthesis starts

Answer 9

proerythroblast

Question 10

calculations of white blood cell count

Answer 10

• 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

Question 11

normal wbc

Answer 11

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

Question 12

wbc dilating fluid

Answer 12

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

Question 13

physiological leucocytosis and leucocytopenia

Answer 13

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

leucocytopenia
- starvation

Question 14

pathological - leucocytosis and leucocytopenia

Answer 14

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

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

Question 15

where are wbcs produced?

Answer 15

monocytes + granulocytes - bone marrow

lymphocytes - bone marrow and lymphoid tissues

Question 16

errors of wbc

Answer 16

• 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

Question 17

hayem’s fluid

Answer 17

Hayem’s fluid:

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

Question 18

what happens to wbc in rbc count

Answer 18

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

Question 19

counting of rbcs

Answer 19

• 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

Question 20

what is anemia

Answer 20

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.

Question 21

pathological variation anemia polycythemia

Answer 21

anemia

• Pernicious Anemia
• aplastic anemia
• iron deficiency

polycythaemia
- primary - polycythemia vera (cancerous production of rbcs)
- secondary polycythemia 
• chronic respiratory diseases
• congenital heart disease

Question 22

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

Answer 22

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

Question 23

what prevents the coagulation of blood in this experiment

Answer 23

sodium citrate in saline prevents the coagulation

Question 24

mechanism of hemostasis

Answer 24

• vascular spasm
• platelet plug formation
• blood coagulation
• clot retraction

Question 25

bleeding time prolonged in

Answer 25

idiopathic thrombocytopenic purpura

Question 26

clotting time is prolonged in

Answer 26

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

Question 27

why clotting time more than bleeding time

Answer 27

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

Question 28

different laboratory anticoagulants

Answer 28

• 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.

Question 29

platelet count is increased and decreased in (pathologically)

Answer 29

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

Question 30

functions of platelets

Answer 30

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

Question 31

thrombocytopenic purpura

Answer 31

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

Question 32

clinical significance of reticulocyte

Answer 32

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%

Question 33

wintrobe and westergrens normal values

Answer 33

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

Question 34

wintrobes tube advantage

Answer 34

quantity of blood needed is small | same can be used for pcv

Question 35

normal values of pcv

Answer 35

- males - 40-47 | - females - 37% to 45%

Question 36

pcv

Answer 36

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

Question 37

mcv mch mchc

Answer 37

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%

Question 38

normal fragility

Answer 38

0.46-0.34 % of nacl

Question 39

osmotic fragility imp

Answer 39

- 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

Question 40

fragility is altered in

Answer 40

``` increased - venous blood stored blood hereditary or acquired spherocytosis sickle cell anemia ``` decreased - thalassemia iron deficiency anemia

Question 41

due to mismatching

Answer 41

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

Question 42

spirometry

Answer 42

fev fev1 fev2 - obstructive jaundice dec | fev1 and fev2 normal and vc is decreased

Question 43

dyspnoeic index

Answer 43

mvv - rmv / mvv x 100 normal - 90 and reduced below 60-70

Question 44

hb normal values

Answer 44

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