Routine and Point of Care Testing

Question 1

Hemoglobin

Answer 1

• Protein in RBC which carries oxygen to tissues and CO2 the lungs.
• males have a higher normal value than women

FYI
Normal values:
Male adult: 13.5 - 17.5 g/dL
Female adult: 12.0 - 16.0 g/dL

Question 2

Hemoglobin Measurement

Answer 2

• Whole blood mixed with Drabkins Reagent.
• Ferricyanide converts ferrous (++) to the ferric (+++) = methemoglobin.
• methemoglobin + potassium cyanide = stable pigment cyanmethemoglobin.
• read on spectrophotometer at 540 nm.
• Incorporates all types of hemoglobin except sulfhemoglobin

Question 3

Hematocrit

Answer 3

• Percent of RBC volume in whole blood (RBC, WBC, platelets, and plasma/serum)
• Requires centrifugation
• RBC / Total = %

Question 4

What does the Hematocrit test evaluate?

Answer 4

• Anemia (decrease of red blood cells),
• Polycythemia (increase in red blood cells),
• Dehydration (Higher hematocrit due to low plasma)
• Blood transfusion decisions and the effectiveness of those transfusions.

Question 5

Rule of Three

Answer 5

Hgb (g/dL) x 3 = Hct (%) +/- 3

Question 6

Mean Cell Volume (MCV)

Answer 6

• average volume of the RBC

MCV(fL) = Hct(%)/RBC x 10

Normal = 80 - 100 fL (normocytic)
Increased—macrocytic
Decreased—microcytic

Question 7

What can the RDW be used to tell?

Answer 7

Anisocytosis

RDW = Coefficient of variation (SD/Mean)

Question 8

Mean Cell Hemoglobin

Answer 8

• average weight of hemoglobin in the RBC

MCH(pg) = Hgb(g/dL)/RBC x 10

Normal = 27 - 31 pg
Increased—macrocytic anemias and some spherocytoses
Decreased—microcytic anemia and normocytic, hypochromic anemia

Question 9

Mean Cell Hemoglobin Concentration

Answer 9

• average expression of hemoglobin per RBC

MCHC(%) = Hgb(g/dL)/Hct(%) x 100

Normal = 32 - 36%
Increased—hyperchromia (spherocytes)
Decreased—hypochromia

Question 10

Automated Cell Counting

Answer 10

Impedance = the coulter principle

• Break in electrical current causes a “blip”
• Counts WBC, RBC, and platelets (Size and Amount)

Flow cytometry

• a break in the light= a cell
• amount of reflection/scattered light = size of cell, inclusions in cell, nucleus morphology

Question 11

Hemocytometer

Answer 11

Volume = (1 x 1 x 0.1)

• used for counting WBC and RBCs
• Acetic acid is used to break up RBC when looking at WBCs
• WBCs counted under 10x objective
• RBCs counted under 40x objective

Question 12

Body Fluids used in Blood Cell Counting

Answer 12

• Spinal fluid
• Pleural fluid
• Synovial fluid
• Some are thicker than others and can clog automated instruments

Question 13

Dilutions

• WBC
• Platelets
• Body Sample

Answer 13

• WBC: usually 1:10 or 1:20
• Platelets: usually 1:100 or 1:10
• Body fluids: determined by sample appearance

Question 14

WBC Count Formula

Answer 14

= # of WBC counted * 1/(volume*# squares counted) * dilution

Question 15

Point of Care Testing

Answer 15

• Diagnostic testing at or near the site of patient care
• Rarely performed by trained lab personnel
• Quality assurance remains the responsibility of the laboratory
• Tests are all FDA approved

Question 16

CLIA Classification of Point of Care Testing

Answer 16

Waived tests - simple tests with little risk of error

Examples- Hematocrit, Hemoglobin, Cell and Platelet Counts

Other tests:
Moderately complex & Complex

Question 17

Point of Care Program requires:

Answer 17

• Clear administrative responsibility
• Well-written procedures
• Training
• Quality control
• Proficiency testing
• Equipment maintenance