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HEMA > Week 7 Lab: Macro/Micro Hct Determination, ESR > Flashcards

Week 7 Lab: Macro/Micro Hct Determination, ESR Flashcards

1
Q

The word hematocrit means to?

A

separate blood

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2
Q

Hematocrit is often referred as?

A
  • packed cell volume
  • volume of erythrocytes
  • reading of packed cells
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3
Q

Hematocrit is the ratio of?

A

packed RBC to plasma

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4
Q

This test measures the proportion of red blood cells to plasma in the peripheral blood.

A

Hematocrit Determination

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5
Q

The hematocrit (Hct) is part of?

A

CBC

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6
Q

Hematocrit test directly measures?

A

RBC mass

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7
Q

The results of hematocrit are expressed as?

A

volume of packed cell in whole blood (PCV)

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8
Q

Hematocrit is an important measurement in the determination of?

A

anemia or polycythemia

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9
Q

Hematocrit is a good simple screening test for?

A

anemia

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10
Q

True or false: Hematocrit results are reliable.

A

True

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11
Q

Specimen of choice for Macrohematocrit method?

A

EDTA blood

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12
Q

Materials for Hct Determination by Macrohematocrit Method?

A
  • Wintrobe tube
  • Long stem pipette
  • Centrifuge
  • Anticoagulated blood
  • Pasteur pipette
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13
Q

Length of Wintrobe tube? (accrdg. to picture)

A

11.5 cm

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14
Q

Size of the bore of Wintrobe tube? (accrdg. to picture)

A

2.5 mm

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15
Q

The Wintrobe tube has how many graduations?

A

two (1 ascending and 1 descending)

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16
Q

What are the colors of the graduations in a Wintrobe tube?

A

red and white

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17
Q

Starting from the top, the red graduations of the Wintrobe tube are arranged in what order?

A

ascending: 0-10

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18
Q

Starting from the top, the white graduations of the Wintrobe tube are arranged in what order?

A

descending: 10-0

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19
Q

Procedure for Macrohematocrit method?

A
  1. (Mix): Mix the blood.
  2. (Fill): With the use of a long pipette, fill the wintrobe tube to the 10 mark.
  3. (Centrifuge): Centrifuge the blood for 30 minutes.
  4. (Read): Read the height of the packed red cell on the scale at the right side of the tube, which is graduated from 0-10 cm from the bottom to top, and read upward.
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20
Q

After centrifugation during macrohematocrit method, packed RBC is?

A

slanted

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21
Q

Since packed RBC is slanted after centrifugation during macrohematocrit method, which point of the slant will you use to measure?

A

lowest point/lower meniscus

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22
Q

Which graduations of the Wintrobe tube must be used for hematocrit testing?

A

white graduations

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23
Q

True or false: Reading the results for hematocrit testing on the Wintrobe must be at eye level.

A

True

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24
Q

True or false: You should include the buffy coat when reading the results for hematocrit testing via the macro method.

A

False. Do not include the buffy coat.

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25
Q

Formula for hematocrit testing?

A

(Packed cell volume/Total volume used) x 100

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26
Q

Unit for hematocrit testing?

A

percent

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27
Q

Causes of falsely-increased hematocrit results via macrohematocrit method?

A
  • Undercentrifugation
  • Prolonged standing
  • Inclusion of Buffy coat
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28
Q

Causes of falsely-decreased hematocrit results via macrohematocrit method?

A
  • Over centrifugation
  • Hemolyzed sample
  • Increased concentration of anticoagulant
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29
Q

Reference values for hematocrit?

A
  • Male: 40-54 % or 0.40-0.54 L/ L
  • Female: 35-49 % or 0.35-0.49 L/L
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30
Q

Materials for Hct Determination by Microhematocrit Method?

A
  • Capillary tube
  • Sealing clay
  • Microhematocrit reader
  • Microhematocrit centrifuge
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31
Q

Why do we use a blue capillary tube instead of the red one?

A

Our specimen of choice is EDTA blood, which already contains anticoagulant. The capillary tube with the red band has heparin. Therefore, if we use it, the EDTA blood will mix with the heparin. The blue band capillary tube is preferred because it is plain.

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32
Q

Procedure for Microhematocrit method?

A
  1. Fill a non-heparinized capillary tube up to 3/4 full. Fill blood on the side with no color band.
  2. Seal the other end of the tube (colored end). Hold horizontally at a 90-degree angle and rotate slightly. A 4 mm clay on the tube is recommended.
  3. Centrifuge for 5 minutes at full speed of 12,000 rpm. Balance the tubes on the microhematocrit centrifuge, the clay should face the outside (clay touching the rubber).
  4. Read results using a microhematocrit reader.
33
Q

What are the 3 lines in the Microhematocrit reader?

A
  • horizontal line
  • slope line
  • movable line
34
Q

Sources of error for hematocrit results via microhematocrit method?

A
  • Incomplete sealing of the microhematocrit tubes - falsely low results
  • Inadequate centrifugation
  • Time and speed of centrifugation
  • Overanticoagulated
35
Q

Inflammation causes red blood cells to?

A

stick together and sink faster

36
Q

A non-specific measurement to detect and monitor an inflammatory response to tissue injury in which there is a change in the plasma concentration of acute phase proteins.

37
Q

ESR is similar with what test?

A

CRP (C-Reactive Protein) test because it is also a non-specific test for inflammation

38
Q

ESR allows blood to sit in a vertical position for a period of?

39
Q

ESR is reported in?

40
Q

ESR is affected by what 3 factors?

A
  • red cells
  • plasma compositions
  • mechanical/technical factors
41
Q

True or false: Red cells attract each other because of their net negative charge.

A

False. They repel each other.

42
Q

In disease states, plasma protein concentration changes, causing a reduction in the negative charge of the RBCs and consequent formation of?

43
Q

Rouleaux leads to?

A

larger mass and an increased sedimentation velocity

44
Q

True or false: The larger the particle, the faster its rate of fall.

45
Q

True or false: Macrocytes settle more rapidly than microcytes.

46
Q

RBCs with shape alterations (sickle cells and spherocytes) are unable to form rouleaux. Thus, ESR is?

47
Q

Which conditions reduce the ability of RBCs to form large aggregates?

A

Anisocytosis and poikilocytosis

48
Q

Anisocytosis and poikilocytosis cause ESR to?

49
Q

Because severe anemia has low numbers of RBCs, aggregation and rouleaux formation are?

50
Q

Because severe anemia has low numbers of RBCs, aggregation and rouleaux formation are increased. Thus, ESR is?

51
Q

Single most important factor determining the ESR?

A

Plasma factors

52
Q

Rouleaux and aggregation are controlled primarily by levels of?

A

acute phase proteins (fibrinogen, alpha-1 globulin, alpha-2 globulin), increasing as these three plasma protein levels are increased in the plasma

53
Q

A tilt of 3 degrees can cause errors up to?

54
Q

The rack holding the tubes in ESR should not be subject to?

A

any movement or vibrations

55
Q

Increased temperature causes ESR to?

56
Q

True or false: The ESR represents a specific response to tissue damage and inflammation and denotes the presence of disease.

A

False. The ESR represents a NONspecific response to tissue damage and inflammation and denotes the presence of disease, but not its severity.

57
Q

Conditions showing elevated ESR?

A
  • pregnancy (after 3rd month)
  • acute and chronic infections
  • rheumatic fever
  • rheumatoid arthritis
  • myocardial infarction
  • nephrosis
  • acute hepatitis
  • menstruation
  • tuberculosis
  • macroglobulinemia
  • cryoglobulinemia
  • hypothyroidism
  • hyperthyroidism
58
Q

Conditions showing decreased ESR?

A
  • polycythemia
  • congestive heart failure
  • hypofibrinogenemia
  • presence of red cell abnormalities (poikilocytosis, spherocytes, and sickle cells)
59
Q

2 methods for ESR?

A
  1. Wintrobe and Landsberg Method
  2. Westergren Method
60
Q

Specimen of choice for Wintrobe and Landsberg Method?

A

EDTA anticoagulated blood

61
Q

Procedure for Wintrobe and Landsberg Method?

A
  1. Mix the blood
  2. With a long stem pipette, fill the Wintrobe tube up to 0 mark (no air bubbles)
  3. Place the tube in a vertical position on the rack for 60 minutes
  4. Record the level of sedimented ESR from the scale on the left side (red) of the tube. Read downward
62
Q

Specimen of choice for Westergren method?

A

Citrated blood (0.109M trisodium citrate)

63
Q

Procedure for Westergren method?

A
  1. Mix the blood
  2. Place the Westergren tube into the blood sample, making sure that the blood reaches the 0 mark on the tube
  3. Place in a rack for 60 minutes
  4. Read the graduations downward
64
Q

Reference Value for Westergren ESR in women?

A

Women: 0-15 mm/hr

65
Q

Reference Value for Westergren ESR in men?

A

Men: 0-10 mm/hr

66
Q

Reference Value for Westergren ESR in children?

A

Children: 0-10 mm/hr

67
Q

Reference Value for Wintrobe and Landsberg ESR in women?

A

Women: 0-20 mm/hr

68
Q

Reference Value for Wintrobe and Landsberg ESR in men?

A

Men: 0-9 mm/hr

69
Q

Stages of ESR?

A
  1. Initial rouleaux formation/lag phase (10 minutes) – sedimentation rate is slight
  2. Rapid settling of RBCs/Rapid packing of cells/decantation (40 minutes) - sedimentation is more rapid and constant
  3. Final sedimentation of RBCs (10 minutes) – sedimentation rate is slow because of the accumulation of RBCs at the bottom of the tube
70
Q

Standard/Original Westergren dimensions?

A

300.5 mm long (± 0.5 mm), tube bore 2.65 mm (± 0.15 mm)

71
Q

Wintrobe and Landsberg tube dimensions?

A

115 mm long, tube bore 3 mm

72
Q

If the concentration of EDTA is greater than recommended, the ESR will be?

A

falsely low

73
Q

If the ESR stands for more than 60 minutes, the results will be?

A

falsely elevated

74
Q

If it is timed for less than 60 minutes, ESR will be?

75
Q

A marked increase in temperature causes ESR to?

76
Q

A marked decrease in temperature causes ESR to?

77
Q

True or false: Tilting increases sedimentation rate.

78
Q

In ESR, bubbles cause?

A

invalid results

79
Q

In ESR, fibrin clots?

A

invalidate results

HEMA (13 decks)

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