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MIDTERMS > HEMA LAB EVAL > Flashcards

HEMA LAB EVAL Flashcards

1
Q

Hemoglobin Determination
Hemoglobin Methods

A
  1. Copper Sulfate or Specific Gravity Method
  2. Gasometric Method (Oxygen Capacity
    Method)
  3. Chemical Method (Iron Content Method)
  4. Colorimetric Methods
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2
Q

Principle:
Hb will combine and liberate a fixed quantity of O₂. The blood is hemolyzed with ___ and the gas is collected and measured in a ____.

A

Gasometric Method (Oxygen Capacity
Method)
- saponin
- Van Slyke apparatus

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3
Q

Colorimetric Methods

A

A. Visual
1. Direct Matching
2. Acid Hematin
3. Alkali Hematin
B. Photoelectric
1. Oxyhemoglobin Method
2. Cyanmethemoglobin or HiCN method

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4
Q
  • measures plasma hemoglobin
A

Oxyhemoglobin Method

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5
Q

standard and reference method use to
measure hemoglobin
-____ is not converted to ____ and cannot be measured by this method

A

.Cyanmethemoglobin or HiCN method
-Sulfhemoglobin
- cyanmethemoglobin

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6
Q

➢ Blood is diluted in a solution of ___and
___. The hemoglobin is oxidized to ____
by the ____. The ____ then
converts the ___ to ____. The
absorbance is measured spectrophotometrically at ___.

A

Principle of Hemoglobin Det.
- potassium ferricyanide
- potassium cyanide
- methemoglobin
- potassium ferricyanide
- postassium cyanide
-methemoglobin
- cyanmethemoglobin
- 540 nm

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7
Q

-reagent used in hemoglobin determination
- pale and yellow with a pH of ___

A

Modified drabkin’s reagent
7.2 +0.2

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8
Q

Hemoglobin det Specimen:

A
  • whole blood (EDTA)
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9
Q

Reference Range pf Hemoglobin det

A

M: 14-18 g/dL
F: 12-15 g/dL

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10
Q

Factors That Affect Hemoglobin/ Hct/ RBC count Results

A
  1. age
  2. sex
  3. altitude of locality
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11
Q

Modified drabkin’s reagent composition:

A

composition:
Sodium bicarbonate 1 gram
Potassium cyanide 52 mg
Potassium ferricyanide 198 mg
Distilled water 1000 mL

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12
Q

increased hemoglobin level
found in ___, ___, ___

A

Hyperchromia
a. polycythemia
b. dehydration
c. changing from high to low altitudes

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13
Q

– decreased hemoglobin level
found in __

A

Oligochromia
anemias

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14
Q

Sources of Error Correction____
1. Drabkin’s reagent is sensitive to light
2. WBC Count (>20 x 10 ⁹/L)
Platelet Count (>700 x 10⁹/L)
>can cause turbidity and a falsely high result
3. Lipemic sample can interfere and can give a false result
4. Hb S and Hb C maybe resistant to
hemolysis causing turbidity
5. Abnormal globulins found in multiple
myeloma or Waldenstrom
macroglobulinemia may precipitate

A

Correction
1. Store in a brown bottle or in a dark place
2. Centrifuge the solution and measure the supernatant
3. Add 0.01 mL of the patient’s plasma to 5 mL of drabkin’s reagent and used the solution as reagent blank
4. Dilution with distilled water (1:2)
5. Add 0.1 g of potassium carbonate to
drabkin’s reagent

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15
Q

Correction -> Sources of Error??
1. Store in a brown bottle or in a dark place
2. Centrifuge the solution and measure the supernatant
3. Add 0.01 mL of the patient’s plasma to 5 mL of drabkin’s reagent and used the solution as reagent blank
4. Dilution with distilled water (1:2)
5. Add 0.1 g of potassium carbonate to
drabkin’s reagent

A

Correction-> Sources of Error___
1. Drabkin’s reagent is sensitive to light
2. WBC Count (>20 x 10 ⁹/L)
Platelet Count (>700 x 10⁹/L)
>can cause turbidity and a falsely high result
3. Lipemic sample can interfere and can give a false result
4. Hb S and Hb C maybe resistant to
hemolysis causing turbidity
5. Abnormal globulins found in multiple
myeloma or Waldenstrom
macroglobulinemia may precipitate

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16
Q

Decreased Hgb levels

A

Anemia-
Iron defeciency , thalassemia , pernicious anemia
Liver ds , hypothyroidism
Hemorrhage
Hemolytic anemia caused by
o Transfusion of incompatible blood
o Rxn to chemical or drugs
o Rxn to infectious reagent
Various Systemic ds
o Hodgkins ds
o Leukemia
o Lymphoma
o SLE

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17
Q

Explanation of the Test
The hemoglobin determination test is used to :

A
  1. Screen for disease associated with anemia
  2. Determine the severity of anemia
  3. Follow the response to treatment for anemia
  4. Evaluate polycythemia
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18
Q

Increased Hgb levels are found in:
___, __,___

A

a. Polycythemia vera
b. CHF Congestive Hear Failure
c. COPD Chronic obstructive pulmonary disease (COPD)

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19
Q

Variation in Hb levels
a.___
b_____

A

a. Occurs after transfusion, hemorrhages, burns
b. The H and H provide valuable information in an emergency
situation

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20
Q

Interfering Factors of Hgb det

A
  1. People living at high altitudes have
    increased Hb values, as well as inc. Hct and RBC.
  2. Excessive fluid intake cause a decreased Hb.
  3. Normally , the Hb is higher in infants
  4. Drugs
  5. Hb is normally dec during pregnancy
21
Q
  • The panic Hb is ____ a conditions that leads to ___ and ___
  • A value ____ leads to clogging of the capillaries as a result of ____.
A

Clinical Alert
- less than 5.0 g/dl
- heart failure and death
- more than 20 g/dl
- hemoconcentration

22
Q

Packed Cell Volume (PCV)
- is the volume of packed RBCs that occupies a given volume of whole blood.

A

Hematocrit (Hct)

23
Q

Principle:
Anticoagulated whole blood is centrifuged, and the total volume of the red cell mass is expressed as a ___ or ___.

A

Hct/PCV
- percentage or a decimal fraction

24
Q

Methods of Hematocrit Determination

A

A. Macromethods:
1. Wintrobe Method
Double oxalate
2. Haden’s Modification Method
1.1% Na citrate
3. Van Allen’s Method
1.6% Na citrate
4. Sanford – Magath Method
1.3% NA citrate
5. Bray’s Method
Heparin

25
Q

Difference Between • Macro and -Micro Hematocrit Methods
1. Method of blood collection
2. Amount of blood
3. RCF
4. Time of centrifugation
5. Simplicity of technique
Difference Between Micro and Macro Hematocrit Methods
6. ESR
7. Spilling/leakage
8. Breakage of buffy coat
9. Separation of buffy coat
10. Cost of apparatus

A

•Venipuncture
-Skin puncture or venipuncture

•Larger
-smaller

•2,000-2,300 rpm
-10,000-12,000 rpm

•Longer (30 minutes)
-Shorter (3-5 minutes)

•Not simple
-simple

•can be performed
-cannot be performed

•not common
-common

•not common
-common

•complete
- not complete

•expensive
-cheaper

26
Q

Hematocrit Normal value :

A

Women : 35 % - 49 %
Men : 42 % - 54 %

27
Q

Decreased values are indicator of anemia

A

Leukemia , lymphomas
Adrenal insufficiency
Chronic disease
Acute and chronic blood loss

28
Q

Increased Hct values occur in:

A

 Erythrocytosis
 Polycythemia vera
 Shock , when hemocentration rise considererably

29
Q

HCT Interfering Factors

A

High altitude
NV vary with age and gender
Lower value in men and women older than 60 y/o
Severe dehydration from any cause falsely raises the hct

30
Q

Sources of Error in Hematocrit Determination

A
  1. Speed and duration of centrifugation
    >Decrease in centrifugal force will result in more trapped plasma in
    between red cells.
  2. Type and amount of anticoagulant
    Excess anticoagulant causes shrinkage of cells
  3. Integrity in the length and diameter of the tube
  4. Errors in the sample, improper techniques in the collection of venous and capillary blood.
  5. Failure to mix the blood properly before sampling
  6. Leakage of blood in the case of micro hematocrit.
  7. Errors in taking the reading and calculating the result.
31
Q
  • the process of enumerating blood cells
    1
    2
    3
A

Hemocytometry
1. RBC Count
2. WBC Count
3. Platelet Count

32
Q

composed of two raised surfaces each in the shape of a ____ separated by an ____
Total ruled area =___

A

Properties of Hemacytometer/Counting Chamber
Macroscopically:
3-mm x 3-mm square
H-shaped moat
9 sq mm

33
Q

one large square is made up of ____
-each of WBC squares is divided further to_____
-the center square for RBC is subdivided into ____
- the distance between each counting surface and coverslip (depth) is ____
- the total volume is____

A

Properties of Hemacytometer/Counting Chamber
Microscopically:
- nine 1-mm x 1-mm squares
- 16 squares
- 25 smaller squares
- 0.10 mm
- 9 cu mm

34
Q

Hemocytometer Calculations:
General Formula:

A

Total Count = cells counted x dilution factor / area (mm²) x depth (0.1) or
Total Count = cells counted x dilution factor x 10/ area (mm²)

35
Q
  • represents the number of WBCs in ____ of whole blood
    Formula for calculation:
    variables:
    dilution factor= ____
    area counted = ____
    depth correction factor= ___

SI unit =_____

A

White Blood Cell Count
- 1 liter of whole blood
Formula for calculation:
WBC Count = # of cells counted x dilution factor / area counted (mm²) x depth c.f.
variables:
1:20
4
0.1
WBC Count = # of cells counted x 20/ 4 x 0.1
no. x 10⁹/L

36
Q

WBC Diluting Fluid

A
  1. 2-3% glacial acetic acid
  2. 1% HCl added with 1 drop of methyl violet or crystal violet
37
Q

Criteria of Good WBC Diluting Fluid

Reference Range:

A
  1. should be hypotonic
  2. should color/stain the nuclei of white blood cells

4.5-11.5 x 10⁹/L

38
Q
  • WBC Count must be corrected if ____ are counted on___ since ___ present in the sample are not lysed by the diluting fluid and counted as WBC
    Formula:
A

Corrected WBC Count Rule
- 5 or more NRBCs
- differential count
- NRBCs

Corrected WBC Count = uncorrected WBC count x 100/ # of NRBCs per 100 WBC + 100

39
Q

Red Blood Cell Count
General formula:
Variables:
area correction factor = _
depth correction factor = __
dilution factor = ___

SI unit: ___

A

RBC Count = # of cells counted x area c.f. x depth c.f. x dilution factor

area correction factor = 5
depth correction factor = 10
dilution factor = 1:200

RBC Count = # of cells counted x 5 x 10 x 200 or
RBC Count = # of cells counted X 10,000
SI unit = no. x 10¹²/L

40
Q

RBC count Reference Range:

A

Male: 4.6-6.0 x 10ˈ²/L
Female: 4.0-5.4 x 10ˈ²/L

41
Q

RBC Diluting Fluids

A
  1. Hayem’s Fluid
  2. Gower’s Solution
  3. Toisson’s Fluid
  4. Dacie’s or Formol Citrate Solution
  5. Bethel’s Fluid
  6. NSS or Physiologic Salt Solution
  7. 3.8% Sodium Citrate
42
Q

❖ this is considered the best diluent .
❖ It keeps for a long time and does not alter the shape of the cells.

A

Dacies Fluid ( Formol Citrate)
40 % formaldehyde 10 ml
3% w/v disodium citrate 990 ml

43
Q

Hayem’s Diluting Fluid

A

Mercuric chloride 1.0 gram
Sodium Sulfate Anhydrous 4.4 grams

44
Q
  • prevents rouleaux formation
A

Gower’s Solution
- Sodium sulfate anhydrous 12.5 grams
- Glacial acetic acid 33.3 ml
- Distilled water 200 ml

45
Q

high specific gravity and stains the
WBC.

A

Toisson’s Fluid
Na chloride 1.0 gram
NaSo4 8.0 grams
Glycerin 30.0 grams
Methyl violet 0.25 grams
Distilled Water 180 ml

46
Q
  • used in emergency cases,
    used in the presence of ___ and ____
A

Normal Saline Solution
rouleaux formation and autoagglutination of cells.

Na chloride- 0.85 grams
Dist Water - 100 ml

47
Q

3.8 % Sodium Citrate

A

Sodium Citrate 3.8 grams
distilled water 100 ml

48
Q

Criteria of Good RBC Diluting Fluid

A
  1. Must be an isotonic solution
  2. Has a good preservative
  3. Does not initiate the growth of molds and yeast
  4. With a high specific gravity
  5. With buffer action
  6. Cheap and easy to prepare
49
Q
  • the value of the ____ should be ___ the value of ___
  • This rule applies only to specimens that have ____ and ____
    Example:
    Hb = 12 g/dL
    Hct = ___
A

Rule of Three
hematocrit
three times
hemoglobin (+3)
normocytic
normochromic erythrocytes
36%

MIDTERMS (19 decks)

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