HEMA LAB EVAL Flashcards by Queenie Mae

Hemoglobin Determination
Hemoglobin Methods

Copper Sulfate or Specific Gravity Method
Gasometric Method (Oxygen Capacity
Method)
Chemical Method (Iron Content Method)
Colorimetric Methods

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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 ____.

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

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Colorimetric Methods

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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measures plasma hemoglobin

Oxyhemoglobin Method

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

.Cyanmethemoglobin or HiCN method
-Sulfhemoglobin
- cyanmethemoglobin

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➢ 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 ___.

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

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

Modified drabkin’s reagent
7.2 +0.2

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Hemoglobin det Specimen:

whole blood (EDTA)

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Reference Range pf Hemoglobin det

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

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Factors That Affect Hemoglobin/ Hct/ RBC count Results

age
sex
altitude of locality

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Modified drabkin’s reagent composition:

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

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increased hemoglobin level
found in ___, ___, ___

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

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– decreased hemoglobin level
found in __

Oligochromia
anemias

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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

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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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

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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Decreased Hgb levels

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

Screen for disease associated with anemia
Determine the severity of anemia
Follow the response to treatment for anemia
Evaluate polycythemia

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

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

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Variation in Hb levels
a.___
b_____

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

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Interfering Factors of Hgb det

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People living at high altitudes have
increased Hb values, as well as inc. Hct and RBC.
Excessive fluid intake cause a decreased Hb.
Normally , the Hb is higher in infants
Drugs
Hb is normally dec during pregnancy

The panic Hb is ____ a conditions that leads to ___ and ___
A value ____ leads to clogging of the capillaries as a result of ____.

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

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

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Hematocrit (Hct)

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

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Hct/PCV
- percentage or a decimal fraction

Methods of Hematocrit Determination

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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

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

•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

Hematocrit Normal value :

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

Decreased values are indicator of anemia

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

Increased Hct values occur in:

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

HCT Interfering Factors

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

Sources of Error in Hematocrit Determination

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.

- the process of enumerating blood cells 1 2 3

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

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

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

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____

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

Hemocytometer Calculations: General Formula:

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)

- represents the number of WBCs in ____ of whole blood Formula for calculation: variables: dilution factor= ____ area counted = ____ depth correction factor= ___ SI unit =_____

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

WBC Diluting Fluid

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

Criteria of Good WBC Diluting Fluid Reference Range:

1. should be hypotonic 2. should color/stain the nuclei of white blood cells 4.5-11.5 x 10⁹/L

- 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:

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

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

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

RBC count Reference Range:

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

RBC Diluting Fluids

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

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

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

Hayem’s Diluting Fluid

Mercuric chloride 1.0 gram Sodium Sulfate Anhydrous 4.4 grams

- prevents rouleaux formation

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

high specific gravity and stains the WBC.

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

- used in emergency cases, used in the presence of ___ and ____

Normal Saline Solution rouleaux formation and autoagglutination of cells. Na chloride- 0.85 grams Dist Water - 100 ml

3.8 % Sodium Citrate

Sodium Citrate 3.8 grams distilled water 100 ml

Criteria of Good RBC Diluting Fluid

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

- the value of the ____ should be ___ the value of ___ - This rule applies only to specimens that have ____ and ____ Example: Hb = 12 g/dL Hct = ___

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

HEMA LAB EVAL Flashcards

(49 cards)