MIDTERMS: L1 - HEMOGLOBIN AND HEMATOCRIT DETERMINATION Flashcards

1
Q

Estimation or measurement of hemoglobin concentration of a blood sample

A

HEMOGLOBINOMETRY

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2
Q

Per gram of Hb:
O2 -
Fe2 -

A
  1. 34 mL O2

3. 47 mg Fe2+

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3
Q

MOTF
Chemical method
- Indirect estimation
of the hemoglobin based on the oxygen concentration of the blood
Gasometric method
- Indirect estimation
of the hemoglobin based on the concentration of iron

A

BOTH F
Gasometric method
- Indirect estimation
of the hemoglobin based on the oxygen concentration of the blood
Chemical method
- Indirect estimation
of the hemoglobin based on the concentration of iron

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4
Q

Normal Hemoglobins

A
  • Oxygenated Hb

- Reduced/Deoxygenated Hb

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5
Q

3 Hemoglobin Derivates

A
  1. Methemoglobin/Hemiglobin (Hi)
  2. Sulfhemoglobin (SHb)
  3. Carboxyhemoglobin (COHb)
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6
Q

The iron part of the hemoglobin has

been oxidized to ferric state

A

Methemoglobin/Hemiglobin (Hi)

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7
Q

Color of blood in Methemoglobin/Hemiglobin (Hi)

A

Chocolate brown color

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8
Q

Color of blood in Sulfhemoglobin (SHb) and Carboxyhemoglobin (COHb)

A

Sulfhemoglobin (SHb) - Mauve lavander color

Carboxyhemoglobin (COHb) - Cherry red color

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9
Q

Methods of Hemoglobin determination:

A
  1. Physical: Gravimetric
  2. Colorimetric
  3. Spectrophotometric 4. Automated
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10
Q

MOTF
Physical Method
1. Qualitative - not give value what hb level is, just indicate hb concentration if adequate or not
2. Commonly used to screen blood donors

A

Both T

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11
Q

SG of Blood

A

1.045-1.065 (average 1.055)

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12
Q

Reagent used in Physical Method

A

Copper sulfate of a particular density

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13
Q
MOTF
Physical Method
1. Sink - Blood Hb is >12.5 g/dL (patient passed)
2.  Suspended - blood HB is < 12.5 g/dL
(patient failed)
A

Both T

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14
Q

MOTF
Physical Method
1. Blood floats: SG of blood < SG of CuSO4 - Fail the potential donor

  1. Blood sinks: SG of blood > SG of CuSO4 - Accept the potential donor
A

Both T

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15
Q

T or F
Male: SG 1.055 = 13 g/dL of Hb

Female: SG 1.053 = 12 g/dL of Hb

A

T

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16
Q

Other term for Colorimetric Method

A

Acid Hematin Method

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17
Q

COLORIMETRIC METHOD
1. Quantitative estimation
2. Based on the conversion of the hemoglobin into acid hematin with the addition of:
Reagents: 0.1N Hydrochloric acid, dH2O

A

Both T

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18
Q

Reagents used in Colorimetric Method

A

0.1N Hydrochloric acid, dH2O

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19
Q

0.1N Hydrochloric acid will oxidize the hemoglobin into acid hematin which will have a _____ color

A

Brown

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20
Q

Used to adjust the sample until it matches the color comparator

A

Distilled H20

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21
Q

Where we put in blood samples and than add our reagent 0.1N Hydrochloric acid to convert hemoglobin to acid hematin

A

Hemometer tube

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22
Q

Where reagent is stored ( 0.1N Hydrochloric acid/ dH20)

A

Amber bottle

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23
Q

Reagents used for cleaning

different pipettes regardless if WBC or Sahli pipette (In correct order, with their purpose0

A
  1. Bleach (zonrox) - to remove the blood in the
    pipette, should be dispensed
  2. Water - make sure that no blood sample is left
    in the pipette
  3. Acetone - used to dry the pipette
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24
Q

T OR F

Acid hematin method will able to measure our different derivatives

A

False (Cannot measure diff derivatives)

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25
Q

MOTF

  1. More accurate than photometric
  2. Routinely used in bigger hospital
  3. Has low specificity and accuracy
A

Only 3 is correct

  1. False - photometric is more accurate
  2. False - Not routinely used in big hospitals, can use in small labs
  3. True
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26
Q

Visual method that utilizes the Drabkin’s reagent

A

PHOTOMETRIC METHOD

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27
Q

Photometric method (a reference method) recommended by

A

International

committee on standardization in hematology as well as CLSI

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28
Q

Photometric Method - able to measure all types of hemoglobin except _______

A

Sulfhemoglobin

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29
Q

Photometric Method is also known as

A

Cyanmethemoglobin/Methemoglobin cyanide method

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30
Q

Drabkin’s reagent components - enumerate and its functions

A
  1. Potassium cyanide -
    oxidizes Hb to methemoglobin
  2. Potassium ferricyanide - donates cyanide ions to form Cyanmethemoglobin or Hemiglobincyanide (HiCN)
  3. Dihydrogen potassium phosphate - prevents precipitation of globulins = maintains pH 7.0-7.4
  4. Non-ionic detergent/ surfactant (saponin) - enhances red cell lysis and lessens turbidity (caused by the presence of proteins in the sample)
31
Q

MOTF
1. Potassium cyanide - Iron to ferric form to produce methemoglobin which is a reversible process

  1. Potassium ferricyanide - donates cyanide ions to form Cyanmethemoglobin or Hemiglobincyanide (HiCN) - irreversible process
A

BOTH T
PC - REVERSIBLE
PF - IRREVERSIBLE

32
Q

MOTF

  1. Photometric method use Spectrophotometer with 540nm
  2. Wavelength used is to measure red color using green filter
A

BOTH TRUE

540nm - for red solution

33
Q

Spectrophotometer read absorbance of:

A

Blank
Standard
Qc materials
Patient Samples

34
Q

Known concentration of substance

A

Standard

35
Q

T OR F
Hemoglobin standard is the
only available standard used for Routine Hematologic Procedures

A

TRUE

36
Q
MOTF
1. Regardless of the method of determination as long as it is qualitative with the exception of the gravimetric method which is quantitative, the reference values for hemoglobinometry is the same
2. RV:
Female - 13.5-18.0 g/dL (135-180 g/L0
Male - 12.0-15.0 g/dL (120-150 g/L)
A
BOTH F
1. False - GM is qualitative
2. False - 
Male - 13.5-18.0 g/dL (135-180 g/L0
Female - 12.0-15.0 g/dL (120-150 g/L)
37
Q

Enumerate comments and sources of errors in Photometric method

A
  1. Drabkin’s rgt = photosensitive
  2. Turbidity can falsely increase result:
    3.COHb or Carboxyhemoglobin in heavy smokers takes 1 hour
    to be converted to HiCN (hemoglobin cyanide)
    4.Acidification of cyanide in the rgt releases toxic hydrogen cyanide gas
38
Q

Storage or drabkin’s reagent

A

Amber bottle, stored in dark area, must still be clear and yellow

39
Q

T or F
Any contamination that may cause any level of
turbidity in the solution can affect the result of
the sample since this is an optical method

A

True

40
Q

Correction of Leukocytosis (WBC ct > 20 x 109/L)

A

Correction: centrifuge sx, measure Hb in supernatant fluid to remove WBCs from the solution

41
Q

Blood sx has high concentration of triglycerides that can lead to turbidity

A

Lipemia

42
Q

Correction of Lipemia

A

Correction: 10 uL px plasma + 5 mL of Drabkin’s rgt, use as rgt blank

43
Q

Adds to the optical density of the solution

A

Hb variants (ex. HbS and HbC

44
Q

Correction of Hb variants (ex. HbS and HbC

A

Correction: 1:2 dilution with dH2O and multiply result from the std curve by 2

45
Q

Correction of abnormal globulins

A

Correction: add Sodium carbonate/

KH2PO4 (Dihydrogen Potassium Phosphate0

46
Q

MOTF

  1. Reagent should not be discarded into the sink
  2. Licensed waste disposal service should be contracted
A

BOTH T

47
Q

These are required to be printed on the packaging of the reagents to alert the user of the hazards posed by these chemical substances

A

Pictograms

48
Q

T OR F

1. The hemoglobin in the automated method is part of our complete blood count

A

True

49
Q

3 levels of QC

A

Low, normal, high

50
Q

Potassium cyanide is replaced by:

A

a. Sodium azide (POCTs)
b. Sodium lauryl sulphate (SLS) (autoanalyzers
ex: Sysmex) - can be dispose in sink with added water

51
Q

Clinical significance of Hemoglobinometry:

A
  1. Determine presence and severity of anemia
  2. Assess response to treatment of anemia
  3. Monitor blood loss post-operation
  4. Blood donor screening
  5. Calculation of Red Cell indices
52
Q

Increased Hb is due to - enumerate

A
  1. Polycythemia - increased cellular elements in the blood
  2. Lung disease
  3. VCD
  4. Dehydration
  5. High altitude
53
Q

Decreased Hb is due to - enumerate

A
  1. Anemia

2. Renal diseases

54
Q

Measure the packing of RBCs against the plasma volume

A

Packed Cell Volume (PCV)

55
Q

Unit for reporting hematocrit determination

A

L/L or percentage

56
Q

T OR F

The manual hct method has a very high precision, which has the margin of error of +/- 1%

A

True

57
Q

Manual Hct determination:

A
  1. Macrohematocrit (Wintrobe mtd)

2. Microhematocrit

58
Q

Separation of the formed elements of blood from the plasma through centrifugation

A

Microhematocrit method

59
Q
MOTF
After microhematocrit centrifugation:
1. Red cells packed at bottom
2. Plasma at middle
3. White cells and platelets at top
A

Only 1 true
2 - False (White cells and platelets/Buffy coat at middle)
3 - False (Plasma at top)

60
Q

MOTF

  1. Red cap capillary tube - plain tube
  2. Blue cap capillary tube - heparinized contains heparin
A

BOTH F

  1. Red cap - heparinized
  2. Blue cap - plain, non-anticoagulated
61
Q

MOTF

  1. Open part of tube placed against rubber gasket (at centrifuge)
  2. Closed part placed towards center
A

BOTH F

  1. Open ends - toward center
  2. Closed - agaisnt rubber gasket
62
Q

GRAVITY AND RPM used in centrifugation

A

Gravity: 10,000-15,000g

Rpm: 10,000-12,000 rpm

63
Q

T or F

Do not include the buffy coat in the reading of the value since it would falsely increase the result

A

True

64
Q

Falsely increase or decrease:

Improper sealing

A

Falsely decrease

65
Q

Falsely increase or decrease:

Short draws lead to cell shrinkage

A

Falsely decrease

66
Q

Falsely increase or decrease: Insufficient spining

A

Falsely increase

67
Q

Falsely increase or decrease: Delay

A

Falsely increase

68
Q

Falsely increase or decrease: inclusion of buffy coat

A

Falsely increase

69
Q

Depending on the angle on how you would read the value of your results, that could also affect on how you would interpret the measurement - also known as

A

Parallax effect

70
Q

Variation in size and shape of RBCS

A

Anisopoikilocytosis

71
Q

T OR F

Anisopoikilocytosis can increase trapped plasma (1-3% higher than automated results)

A

True

72
Q

Manual micro Hct will always be lower compared to automated result values because of the trapped plasma phenomenon.

A

False - Manual micro Hct will always be higher compared to automated result

73
Q

Falsely increase or decrease: Dehydration

A

Falsely elevate - plasma volume is lower making packed RBC appear more

74
Q

Reference values for automated method+

A

Male = 40-54% (0.40-0.54 L/L)

Female = 35-49% (0.35-0.49 L/L)