Lab Exam 2 Flashcards

1
Q

What equipment is needed for a safe venipuncture?

A

Gloves, sterile needles, blood collection tubes, needle holder, tourniquet

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2
Q

Veins for venipuncture procedure

A

medial cubital, cephalic (lateral), basillic (medial)

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3
Q

Identify additives, their functions, their volume, and specimen considerations for the color coded tubes

A

LIght blue top:
- sodium citrate
- coagulation
- 2.7 ml

Red top:
- No additives, used for serum separation
- 5-10 ml

Green top:
- Heparin
- 4-8 ml
- electrolytes

Gray top:
- sodium fluoride
- 2-4 ml
- glucose

Lavender top:
- EDTA
- 3-5 ml
- used for CBC

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4
Q

What is the order for drawing proper specimen collection?

A

coagulation, heparin, complete blood count (CBC)

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5
Q

What areas should you avoid when performing venipuncture and why?

A

visible veins, previous IV sites, areas close to major arteries or nerves

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6
Q

Given a set of “out of control” values, calculate the dilution necessary to obtain a value within the analyte assay range and calculate the final result

A

Dilution factor = initial concentration / desired target concentration

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7
Q

What are the parts of a hemocytometer?

A

2 counting chambers

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8
Q

Identify the parts of the 3 dimensions of the counting chamber

A
  1. Length = 1 dimension
    in mm
  2. Area = 2 dimensions in
    mm (L x W = mm2)
  3. Volume = 3 dimensions
    in mm
    (L x W x H = mm3)
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9
Q

Serpentine pattern

A

Allows for continuity

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10
Q

Which border lines count when cells are touching them?

A

top or left. never bottom or right

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11
Q

Proper counting pattern for WBC

A

left, right, down, left

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12
Q

Proper counting pattern for RBC

A

left, right, down, left, middle

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13
Q

How to calculate a WBC and RBC count using the universal formula

A

cells/mm3 = (Average # of cells x depth factor x dilution factor) / area (mm2)

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14
Q

Normal ranges for Manual WBC count

A

Adult - 5.0-10.0 x 10^3 / mm^3
Children - 4.5-12.0 x 10^3/mm^3
Newborn - 9.0-30.0 x 10^3 / mm^3

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15
Q

Name the diluting fluid for WBC count

A

Ammonium oxalate with 100 dilution factor

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16
Q

Normal ranges for manual RBC count

A

Adult male :
4.5-6.0 x 10^12 / L
Adult female:
4.0-5.5 x 10^12/L
Newborn:
5.0-6.3 x 10^6/mm^3

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17
Q

Diluting fluid for RBC count

A

Isotonic saline with 200 dilution factor

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18
Q

Components of hemoglobin molecule

A

Heme (iron containing portion)
Globin (the protein portion)

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19
Q

What do hemoglobin variants contain?

A

Amino acid chains: alpha, beta, gamma, and delta

Alpha chain has 141 amino acids
Beta chain has 146 amino acids

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20
Q

Normal HbA and HbA2 Variants

A

HbA has 2 alpha and 2 beta chains

HbA2 has alpha chains that are paired with 2 delta polypeptide chains

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21
Q

Normal HbF Variant

A

2 alpha chains are paired with 2 gamma chains

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22
Q

Abnormal variants

A

Hb C & S because both of them have amino acid substituions in the beta chain

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23
Q

Hemoglobin derivatives

A

Carboxyhemoglobin (usually bc of smokers), methemoglobin (unable to bind with O2) sulfhemoglobin (from ingesting oxidizing drugs)

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24
Q

Cyanmethemoglobin method for hemoglobin measurement

A

mixing Drabkin’s reagent to a sample of blood forming cyanmethemoglobin. This oxidized blood is read in a
spectrophotometer

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25
Q

Cyanmethemoglobin Method Procedure

A
  1. Pipet 5mL of Drabkin’s
  2. Add 20uL of whole blood
  3. Cover the test tube with parafilm, invert and allow to stand at RT for 10 minutes
  4. Turn on the spec and set the λ to 540
  5. Set the blank curvette that only has Drabkin’s to read 0 abs 100%T.
  6. Read the absorbance of the prepared standards, then the patients and control
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26
Q

Cyanmethemoglobin Reaction

A

RBCs are lysed; the Fe2+ of the released HgB is oxidized to Fe3+ to form methemoglobin. This reacts with the cyanide of K+ cyanide to form cyanmethemoglobin, read by spec at 540λ

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27
Q

What does Drabkin’s reagent contain?

A

iron,potassium, cyanide and sodium bicarbonate (this is a corrosive reagent)

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28
Q

How to find concentration of Hb?

A

Conc = amount / vol g/dl

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29
Q

Hgb Concentration reference ranges

A

Adult males: 13-18 g/dL
Adult females: 11-16 g/dL
Infant :10-14 g/dL

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30
Q

Formula for Hct

A

Volume of RBC / Volume of blood

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31
Q

Reference ranges for Hct

A

Adult males: 40-54%
Adult females: 37-47%

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32
Q

Give 3 reasons for erroneous (wrong) hemoglobin values due to patient considerations

A

Hemodilution: if pt has IV
Dehydration: concentration changes
Hemolysis: shaking tube

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33
Q

Extruded

A

being released from the cell

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34
Q

What are some factors that can affect hemoglobin levels?

A

Age, altitude, gender, and diet

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35
Q

Preparation of a Standard curve

A

x axis - concentration of Hb (g/dL)
y axis - Aborsbance hgb values

straight line

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36
Q

Hemoglobin absorbance values in men

A

14.0-17.5 g/dL

37
Q

Hemoglobin absorbance values in women

A

12.3-15.3g/dL

38
Q

Hemoglobin absorbance values in children

A

16.5 g/dL - 14.0 g/dL

39
Q

Hematocrit definition

A

a measure for the volume % of RBCs in WB commonly used as an indirect method to assess packed cell volume (PCV) = hematocrit value. PCV refers to the volume occupied by packed red blood cells in a given volume of blood after centrifugation.

40
Q

What is the hematocrit’s role in assessing packed cell volume?

A

It provides important information about the concentration of RBCs in the blood and aids in the diagnosis and monitoring of various hematological conditions.

41
Q

What is shown in a microhematocrit tube after centrifugation?

A

Plasma, buffy coat (WBC and platelets) , RBCs, sealant

42
Q

What could low hematocrit values mean?

A
  • Anemia
  • Bleeding/Hemorrhage
  • Cancer/Leukemia
  • Chronic illness
  • Increased RBC destruction
  • Not enough folate, iron, B6 and B12 in
    diet
  • Bone marrow problems
43
Q

What could high hematocrit values mean?

A
  • Polycythemia vera
  • Heart Disease
  • High altitude
  • Hemochromatosis
44
Q

Hematocrit Normal Values

A

Reference Values
* - Adult male 40 - 54%
* - Adult female 37 - 47%
* - Newborn 41 – 61%
* - Infant 32 – 42%

45
Q

Micro-pipetting technique

A
  1. Mix the EDTA tube
  2. Micro-pipette 2 tubes with 3/4 of the blood sample
  3. seal the tube with crip-o-seal
  4. Unscrew top of micro-hematocrit centrifuge
  5. load micros to centrifuge, screw the top back on tight and set for 5 minutes
46
Q

How to measure microhematocrit tube post-centrifuged?

A

Load micro on reader with blood facing center, set bottom wheel to 100, move top wheel until curve hits top of plasma. Move both wheels until curve hits intersection of blood and plasma, read results of both tubes

The results should range +/-2% and the average is reported

47
Q

Sources of error in hemoglobin testing

A

Improper pipetting, dirty or scratched curvettes, Drabkin’s solution deterioration (must be kept in dark bottle to prevent exposure to light)

48
Q

Sources of error due to condition of pt and how

A

Lipemic samples: high lipids are cloudy,
interfering with light absorption
Increased WBC levels: interfere with light absorption
Presence of HgB C or HgB S: resistant to
cyanide lysing of the RBCs, causing decreased HgB levels
Increased protein levels: Light
absorption issues

49
Q

Sources of error in hematocrit testing

A

Incorrect Centrifugation Speed or Time, Overfilling or Underfilling of Hematocrit Tubes, Air Bubbles, Equipment Calibration

50
Q

Reference range for MCH

A

27-33 pg

51
Q

MCH

A

Mean Corpuscular Hbg (pg) = Hgb concentration / RBC count x 10

52
Q

MCV

A

Mean Corpuscular Volume (fL) = Hct/RBC count x 10

53
Q

MCHC

A

Mean Corpuscular Hemoglobin Concentration (g/dL) = Hgb concentration / HCT (RBC volume) x 10

54
Q

Reference range in normal adults for MCV

A

80-96 fL

55
Q

RBC Indices and how they classify anemias

A
  1. Normochrmoic- normocytic
  2. Macrocytic
  3. Hypochromis- microcytic
56
Q

Anisocytosis

A

variation in size of RBC

57
Q

ESR

A

the rate at which RBCs in anticoagulated whole blood descend in a standardized tube over a period of one hour

58
Q

Hematopoiesis

A

overall blood cell maturation and function that equates to blood cell production

59
Q

Hemoglobinopathies

A

Disorder in which structurally abnormal Hb is considered to play an important role pathologically

Structurally abnormal Hb has an amino acid subsitution

Usually from B chain abnormalities

60
Q

Oxyhemoglobin

A

Hb carrying O2

61
Q

Reduced Hb

A

Hb returning to the lungs with CO2 from the tissues

62
Q

Megakaryocytes

A

These cells turn into platelets

63
Q

Mononuclear phagocytic system

A

This is how worn out RBCs are removed from blood

64
Q

Poikilocytes

A

an increase in abnormal red blood cells

65
Q

Polychromasia

A

more immature red blood cells than what’s considered normal

66
Q

Polychromatophilia

A

how red blood cells look under a microscope when the cells are stained with special dyes. It means there is more staining than normal with certain dyes. The extra staining is due to an increased number of immature red blood cells (RBCs)

67
Q

What do reticulocytes % indicate and what do they look like?

A

The percentage of reticulocytes in the blood stream tells us the degree of RBC production from the bone marrow; has RNA in them

68
Q

Supravital stains

A

This stain shows us the RNA in the reticulocytes and by using cresyl blue or methylene blue

69
Q

Another name for platelets

A

thrombocytes

70
Q

What do myeloid progenitors differentiate into?

A

Erythrocytes, platelets, neutrophils and monocytes

71
Q

Stages of maturation

A

Rubriblas, prorubricyte, rubricyte, metarubricyte, reticulocyte, erythrocyte

72
Q

Oxygen Dissocation Curve

A

Trend that shows oxygen leaving the Hb to the tissues making the Hb from OxyHb to Reduced Hb

73
Q

Factors that change when there is a shift in an O2 curve

A

Temp, 2-3 DPG (a chemical), pH, Hb,

74
Q

Normal Leukocytes

A

Polymorphonuclear neutrophils, band neutrophils, lymphocytes, monocytes, eosinophils, basophils

75
Q

What do band neutrophils look like?

A

They look like an embryo and egg lol

76
Q

What do monocytes look like?

A

Deformed globs

77
Q

What do lymphocytes look like?

A

giant yolk in an egg

78
Q

What do basophils look like?

A

purple splotch with blue black granules

79
Q

What do eosinophils look like?

A

orange granules with distinct lobes

80
Q

What do polymorphonuclear neutrophils look like?

A

3 or 4 distinct lobes

81
Q

How to clean hemacytometer

A

70% alcohol with lens paper and clean before and after each use

82
Q

The Hemacytometer

A

Heavy glass slide with precise measurements as defined by the National Bureau of Standards (NBS)

83
Q

Hemacytometer Counting Area

A

WBC counting area - 4mm
RBC counting area - 0.2 mm
Depth of counting area - 10 mm
Total area - 9mm3

84
Q

Charging the hemacytometer

A

Use a micropipette to fill each chamber and then let it stand for 5 minutes

85
Q

Counting WBCs

A

Count both sides of hemacytometer, find the average, multiply by 10 (depth factor) and 10 dilution factor and divide by 9 (the area)

sides must agree +/- 20 cells

86
Q

Counting RBCs

A

count both sides of hemacytometer, find the average, multiply by 10 (depth) and dilution factor the sides must agree +/- 20 cells

87
Q

Leuk-o-tic Procedure

A
  1. Open eppendorf tube
  2. Aspirate 20uL of WB
  3. Wipe excess blood from tip
  4. Add WB to the tube and rinse/mix
  5. close tube and invert 10x
  6. Let sample sit for at least a minute
  7. Mix the tub several times
  8. Load 10uL to a clean and dry hemacytometer
  9. perform count
88
Q
A