1. 1 Presented by Dr. Shrikant Sonune Guided by Dr Ashok Patil,
Dr Shilpa Kandalgaonkar, Dr Suyog Tupsakhare, Dr Mahesh Gabhane.
Dr. Gaurav Agarwal Investigations & Artifacts in
Hematology
2. Differential count is the percent distribution of various
white cells in the peripheral blood. It is determined from a blood
smear stained with a polychromatic stain. After examination of the
stained smear by using oil immersion objective. The number of each
type of white cells is then expressed as a percentage of the total
number of cells.
3. The stained blood smear also helps to study abnormal
morphology of leukocytes and red cells. Study of blood smear helps
in the diagnosis of various types of anemia, leukemia and detection
of blood parasites.
4. Three major steps involved in differential count are- a)
Preparation of blood smear. b) Staining of blood smear c)
Microscopic examination of stained smear.
5. Requires 1. Slide 2. Spreader 1. Slide Should be clean
Should be free from dust Should be wipe immediately before use 2.
Spreader Should have smooth edge. Should be narrower in breadth
than the slide Almost having 2/3 width
6. A small drop of blood is placed in the central line of a
slide about 1-2 cm from one end. The spreader is placed at an of
450 to the slide then move back to make contact with the drop. Drop
should be spread out quickly along the line of contact of the
spreader with the slide.
7. The movement this occurs the film should be spread by a
rapid, smooth, forward movement of spreader. The drop should be of
such a size that the film is 3-4 cm in length.
8. After smear is prepared then it is fixed with alcohol After
fixation time is over add distilled water. Then add stain over it
for recommended time. Let it be dry Wash under running tap water.
Keep it for drying.
10. It should be tongue shaped 2/3 width of slide 2/3 length of
the slide Thick at one end, thinning out to a smooth rounded
feather edge. Should not touch any edge of the slide. Should be
margin free, except for point of application. It should be
continuous A properly stained slide has a pink tint.
11. Irregular film (A) Too long (B) Too short (C) Irregular
spread (B) Improper shape (D)
12. Discontinuous smear Improper cleaning of slide. Improper
cleaning of finger may incorporate dust on the slide. Thin film
Overzealous force Less than 30 angulations Blood drop too
small
13. Thick film- Very light forces. More 30 angulations Blood
drop Large. Edge formation Improper force Spread of blood drop
Improper direction
14. Irregular film 1. Spreader slide pushed across the slide in
a jerky manner. 2. Failure to keep the entire edge of the spreader
slide against the slide while making the smear. 3. Failure to keep
the spreader slide at a 30 angle with the slide.
15. Failure to keep the spreader slide at a 30 angle with the
slide. Failure to push the spreader slide completely across the
slide. Less than 30 too long film More than 30 too short film.
16. Irregular spread with ridges and long tail: Edge of
spreader dirty or chipped; dusty slide Holes in film: Slide
contaminated with fat or grease Cellular degenerative changes:
delay in fixing, inadequate fixing time or methanol contaminated
with water
18. Too faint Staining time too short Excessive washing after
staining Stain deposit: Stain solution left in uncovered jar or
tray Stain solution not filtered Dirty slides
19. Excessive blue coloration Causes 1. Excessive staining time
2. Buffer in stain is alkaline 3. Old blood smear 4. Blood smear is
too thick
20. The stain must be free of water, which induces RBC
artifacts. Water artifacts may be avoided by fixation of slides or
cover slips in anhydrous methanol before staining.
21. First should see under low power & high power such that
area for counting should be selected. Then counting should be done
under 100X Using z technique.
22. Film quality Stain quality Cell distribution Select the
area for counting of WBC
23. 1. Made one reference point (starting point ) counting is
started. 2. Using z technique the counting is done.
24. Neutrophils (PMN,s) Nucleus 3-5 lobes. Diameter 10-14 m
50-70% WBC Numbers rise with all manner of acute infections ,
especially bacterial. The normal feature seen are
25. Eosinophil Bilobed nucleus 1-5% of WBC Diameter about 10-14
m Contains: eosinophilic pink colour granules The normal feature
seen are
26. Lymphocyte Agranular -No specific granules 20-40% of WBC
Diameter 8-10 m 2 types Small Large The normal feature seen
are
27. MONOCYTE Large nucleus that tends to be oval or kidney
bean- shaped. 2-8% Entering peripheral tissue to become tissue
macrophage
28. BASOPHILS Have numerous granules that stain darkly with
basic dyes. Less than 1% of circulation leukocyte population.
Smaller than neutrophils
29. NORMAL SMEAR THICK AREA, PLUS DRYING ARTIFACTS
30. NORMAL SMEAR TRUE ROULEAUX
31. NORMAL SMEAR DRYING ARTIFACTS
32. a. Cold agglutinin - RBCs will clump together. Warm the
blood at 37 C for 5 minutes, and then remake the smear. c. Rouleaux
- RBCs will form into stacks resembling coins. There is nothing to
correct this.
34. PCV Packed cell volume is the most accurate and simplest of
all test in clinical hematology for detecting the presence of
degree of anemia or polycythemia.
35. Instruments required for Venepuncture Wintrobes tube
Pasteur pipette
36. 5ml of blood. Mix with anticoagulant. Keep it for the
centrifugation at 3000 rpm for 30 min. Record the height of
PCV.
37. Hemolyzed cells parts, other unviable cells also
incorporated into PCV. Actually measures RBC concentration &
not RBC mass Trapping of plasma in RBC column.
38. Faulty readings due to Inappropriate concentration of
anticoagulants. Poor mixing of samples. Insufficient
centrifugation.
39. Hematocrits calculated by automated instruments depend on
correct red cell counts and red cell volumes to arrive at an
accurate hematocrit. Hence, anything affecting the red cell count
or volume measurement will affect the hematocrit. This method is
not as sensitive to the ratio of blood to EDTA as the centrifuged
hematocrit
40. The mean corpuscular volume is the mean value of single red
cell expressed in cu micrometers To calculate mean corpuscular
volume two basic values are required 1. Red cell count in million/
cubic mm 2. Packed cell volume in 100ml blood.
41. Mean corpuscular volume =PCV(packed cell volume) X 10
RBC(106 / mm3 )
42. Average hemoglobin content (weight of Hb) in a single red
blood cell expressed in picogram To calculate the basic values
required are 1. RBC count in million/ cb mm. 2. Hb in g
percent.
43. = Hb in gm% X10 RBC count in million/ mm cb.
44. Relationship between the red cell volume & its degree
or percentage saturation with Hb. It is volumes of red cell
occupied by Hb. It represents actual concentration of Hb in red
cells only.
45. Formula MCHC= Hb per 100ml of blood X 100 PCV per 100ml of
blood
46. It is determined by the direct micrometric measurement of
the red cells in a stained film. The range is 6.9 to 8 micrometer.
Average of 7.5 micrometer.
47. Rate at which red blood settle or sediment. Part of
complete blood test. The determination is useful to check the
progress of the disease.
48. ESR is increased in all conditions where there is tissue
breakdown or where there is entry of foreign proteins in the blood,
except for localized mild infections. The changes of ESR are not
diagnostic of any specific disease.
49. Westergren method Wintrobe method
50. Blood is collected by Venepuncture app 2ml blood is
sufficient. 0.5ml 3.8 % sodium citrate is added as an
anticoagulant. Westergrens pipette is filled with the help of
rubber teat. The pipette is stabilized at stand for one hour at the
end of which readings are noted.
51. Normal Range: - MALE: 0-15 mm after 1st hour - FEMALE :
0-20 mm after 1st hour
52. Blood is collected by Venepuncture app 5ml blood is
sufficient. 0.5ml 3.8 % sodium citrate is added as an
anticoagulant. Wintrobes pipette is filled with the help of rubber
teat. The pipette is stabilized at stand for one hour at the end of
which readings are noted.
53. Normal Range: - MALE : 0-9 mm/after 1st hour - FEMALE: 0-20
mm/after 1st hour
54. Faulty readings due to improperly clean tubes.
Incorporation of air bubbles Disturbances of tube when placed on
stand Calculation errors
55. Cold agglutinins - low red cell counts and high MCVs can be
caused by a increased number of large red cells or red cell
agglutinates. If agglutinated red cells are present, the automated
hematocrits and MCHCs are also incorrect. Cold agglutinins cause
agglutination of the red cells as the blood cools.
56. Cold agglutinins can be present in a number of disease
states, including infectious. If red cell agglutinates are seen on
the peripheral smear, warm the sample in a 37 degrees C heating
block and mix and test the sample while it is warm. Strong cold
agglutinins may not disperse and need to be redrawn in a pre-warmed
tube and kept at body temperature.
57. Fragmented or very microcytic red cells These may cause red
cell counts to be decreased and may flag the platelet count as the
red cells become closer in size to the platelets. Cause an abnormal
platelet histogram. The population is visible at the left side of
the red cell histogram and the right end of the platelet
histogram.
58. Platelet clumps and platelet satellitosis: these cause
falsely decreased platelet counts. Platelet clumps can be seen on
the right side of the platelet histogram. Decreased platelet counts
are confirmed by reviewing the peripheral smear. Always scan the
edge of the smear when checking low platelet counts.
59. 4. Giant platelets: these are platelets that approach or
exceed the size of the red cells. They cause the right hand tail of
the histogram to remain elevated and may be seen at the left of the
red cell histogram. 5. Nucleated red blood cells: these interfere
with the WBC on some instruments by being counted as white
cells/lymphocytes .
61. The process of stoppage of bleeding after blood vessels are
punctured, cut or injured. Involve 4 process 1. Vasocostriction 2.
Platelet plug formation 3. Formation of blood clot 4.
Fibrinolysis
62. It is the time interval between the skin puncture &
spontaneous, unassisted (i. e. without pressure) stoppage of
bleeding.
63. Materials Equipment for sterile finger prick Clean filter
paper Stopwach Normal value 1-5min
64. Method Finger prick & start the stop watch Absorb/
remove the blood drops every 30sec. Note the time when bleeding
stops. This is the end point.
65. 1. Improper blood collection 2. Squeezing of finger 3. Time
to start stopwatch 4. Pressure applied during touching the blotting
paper
66. It is the time interval between the entry of blood into the
glass capillary tube, or a syringe and formation of fibrin thread.
Normal range 3-6min
67. Finger prick Absorb first 2 drops After large drop is
formed Dip one end of capillary so that blood will rise & timer
is started simultaneously Gently break off 1cm bits of glass tube
for each 30 sec interval The time at which the fibrin thread is
formed is the result.
68. Improper finger prick. Inadequate filling of capillaries.
Air bubble incorporation. Improper pressure during breaking the
capillaries. Time to start stopwatch.