Section 14

Question 1

What diluent is used for cyanmethemoglobin method of hgb determination

Answer 1

Drabkins reagent : potassium ferricyanide & potassium cyanide

Question 2

What is the oxidizer in the cyanmethemoglobin method and what does it oxidize

Answer 2

Potassium ferricyanide
Hgb -> methemoglobin

Question 3

What is the purpose of potassium cyanide in the oxidizing process

Answer 3

Ox methemoglobin to cyanmethemoglobin

Question 4

How is hgb determined using cyanmethemoglobin method

Answer 4

Absorbance of cyanmethemoglobin at 540 nm is directly proportional to concentration of hgb

Question 5

How is concentration hgb calculated (equation)

Answer 5

([unknown])/([known])=(abs unknown)/(abs known)

Concentration* dilution factor
Abs known = 45 standard

Question 6

What are sources of error using cyanmethemoglobin method

Answer 6

• Drabkins is sensitive to light,
• high WBC, PLT, or lipemia can interfere with abs measured
• Intravascular hemolysis (hemoglobin not incorporated in cells -> not desired measurement)
• abnormal hgb S or C resists lysis
• abnormal Igs interfere
• carboxyhemoglobin needs to convert before measured

Question 7

What is an alternative method to cyanmethemoglobin method

Answer 7

Sodium laurel sulphate method

Question 8

How does SLS differ from cyanmethemoglobin method

Answer 8

• lyses RBCs and WBCs
• oxidizes iron to ferric state (Fe3)
• become SLS-hgb hemachrome
• absorbs light at 555nm

Question 9

What are the advantages of SLS of cyanmethemoglobin

Answer 9

• lysis of RBC and WBC removes absorbance interference from high WBC count
• removes excess oils from blood, reduces lipemia interaction
• not light sensitive

Question 10

What is hematocrit (hct)

Answer 10

% of whole blood occupied by red cells
Varies with: sex, altitude, age, nutrition and smoking

Question 11

What are the female and male reference ranges for hct

Answer 11

Male: 41.0-53.0%
Female: 36.0-46.0%

Question 12

What is the rule of 3 and when is it used

Answer 12

As a general check calculations match NOT to calculate real values
RBC3= hgb
Hgb3= hct

Question 13

What is mean cell volume (MCV)

Answer 13

Average size of red cells (micro/macro indicator)
MCV=(hct*10)/RBC
RBC= in millions, drop scientific notation

Question 14

MCV reference ranges for females and males

Answer 14

M&F: 80-96 fL

Question 15

What is mean cell hemoglobin (MCH)

Answer 15

Average weight of hgb per RBC (NOT an indicator of chromia, no size correlation)
MCH= (hgb*10)/RBC in millions

Question 16

What is the reference range for females and males for MCH

Answer 16

M&F: 29.0-32.0 pg

Question 17

What is mean cell hemoglobin concentration (MCHC)

Answer 17

Avg amount of red cell vol occupied by hgb (indicator of chromia)
MCHC%= (hgb/hct)*100

Question 18

What is the reference ranges for MCHC

Answer 18

M&F: 33.4-35.5%

Question 19

When can MCHC % be considered lab error (cannot occur)

Answer 19

> 36(except for Sphreocytes)
<30

Question 20

What can cause MCHC to be >36

Answer 20

Cold agglutination
Lipemia
Hemolysis
Icterus

Question 21

Define RDW

Answer 21

Red cell distribution width, amount of red cell size variation
Quantifies anisocytosis

Question 22

What is the RDW reference range

Answer 22

11.5-15 g/L or %

Question 23

How long does it take for reticulocytes to mature

Answer 23

3 total: 2 days in bone marrow, 1 in peripheral blood

Question 24

Why are reticulocyte counts done

Answer 24

To measure the erythropoietic activity of the bone marrow

Question 25

What method is used to count retics

Answer 25

Miller disk Count only retincs in A square Count all cells in B square Count until B=111 A/10 = %retics

Question 26

What stain is used to count retics

Answer 26

Supravital stain with new methylene blue Precipitates RNA from cell to highlight retics

Question 27

What are sources of error in retic counting

Answer 27

Mixing of blood and stain Moisture (refractile cells are NOT retics) Other RBC inclusions

Question 28

When and how to correct retic count for abnormal hct

Answer 28

Correct if hct<45 Corrected= raw retic% *(pt hct/normal hct) Normal = 45

Question 29

What is RPI

Answer 29

Retic production index - retics produced on a daily basis

Question 30

RPI equation

Answer 30

RPI= (corrected retic)/(# days to mature)

Question 31

How to calculate increased # days to mature for retics

Answer 31

Days increase =((pt hct- normal hct)/2)*0.1 1+Days increase= total days to mature in blood

Question 32

Reference range for all retics

Answer 32

Raw, corrected and RPI= 0.5-1%

Question 33

What is a normal bone marrow response for anemia

Answer 33

3% increase

Question 34

What does ESR represent

Answer 34

Erythrocyte sedimentation rate (mm/hr) Amount of rbcs settling in 1 hour Directly proportional to RBC mass Monitor for inflammation

Question 35

List 6 abnormal clinical conditions that increase ESR

Answer 35

- MM - inflammatory disease - RA and collagen diseases - chronic infections - tissue damage or necrosis - autoimmune diseases

Question 36

What are the ESR reference ranges

Answer 36

Male: 0-20 mm/hr Female: 0-30 mm/hr

Question 37

What is the hgb reference range for male and female

Answer 37

Male: 13.5-17.5 g/dL Female: 12-16 g/dL

Question 38

What is the male and female reference range for RBC

Answer 38

Male: 4.5-5.9 Female: 4.0-5.2

Question 39

lipemia affects which red cell indice

Answer 39

MCHC