Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Hematology MLT > Blood Smears, Automated Hematology, ans Manual Cell Counts > Flashcards

Blood Smears, Automated Hematology, ans Manual Cell Counts Flashcards

1
Q

Automated hematology analyzers can electronically (directly) measure (6)?

A
  • RBC
  • WBC
  • PLT
  • MPV
  • Hgb
  • MCV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

From the directly measured paramaters, these quantities can be indirectly calculated (4)?

A
  • Hct
  • MCH
  • MCHC
  • RDW
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What WBCs are in a Three-part WBC Differential?

A
  • Granulocytes
  • Lymphocytes
  • Monocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What WBCs are in a Five-part WBC Differential?

A
  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Newer hematology analyzers may also include what other parameters? (4)

A
  • Relative (%) WBC Count number
  • Absolute WBC count number
  • Reticulocyte analysis
  • Enumeration of nucleated nRBCs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a Delta check?

A

Reviews past patient results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some of the instrument flags?

A
  • R flags
  • Population flags
  • Suspect flags
  • Definitive flags
  • Quantitative flags
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Coulter Principle?

A

“electrical impedence principle” of counting cells

cells are sized and counted by detecting and measuring changes in electrical resistance when a particle passes through an aperture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the electrical impedence methodology?

A
  • Blood sample diluted in saline (good conductor)
  • Two electrodes: negative external electrode located in blood cell suspension. Posistive internal electrode located in glass hollow tube containing aperture.
  • Low frequency DC applied between electrodes
  • Electrical impedence (resistance) occurs as cells pass through sensing aperture causing a change in voltage that generates a pulse.
  • Pulse is measured
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In electrical impedence:

  • The number of pulses = _________
  • SIze of pulse = ____________
A
  1. Number of cells
  2. Cell volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

True/ False

Electrical Impedence - the number of pulses is proportional to the number of cells counted.

&

The size of the voltage is directly proportional to the volume/ Size of the cell.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two counting chambers in the coulter counter?

How is Hgb measured?

A
  • RBC bath - used for RBC and PLT count
  • WBC bath - used for WBC and Hgb determination.
    • RBCs are lysed and Hbg converted to cyanmethhemoglobin. Hgb measured colorimetrically at 540 nm.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Radio Frequency (RF)?

A

RF resistance is a high-volatage electromagetic current flowing between electrodes that detects cell size based in cell density.

Cell wall acts as a conductor, when exposed to high freq. current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What information about the cell do conductivity or RF meansurements provide?

A

Internal characteristics of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What uses a high-frequency pulsating sine wave?

A

Radio Frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The cell interior, or nuclear volume is directly proportional to pulse size or change in _____ _____ resitance.

A

Radio Frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe Optical Light Scatter methodology?

A
  • Blood sample diltuted w/ isotonic diluent.
  • Cells passed through quartz flow cell on which a beam of light (laser) is focused.
  • Light scatters as cells pass through sensing zone.
  • Photodetectors sense and and collect scattered light and convert them into electrical pulse.
  • Number of pulses are directly proportional to number of cells passing through sensing zone.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What cell information is determined from Optical light scatter? (5)

A
  1. Cell count
  2. Size
  3. Cell structure
  4. shape
  5. reflectivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the advantages of automated lab methods?

A
  • Reducted lab cost
  • Faster turnaround time
  • Improved accuracy and precision
  • Fewer manual smears
  • Measurements, counts and differentials done at same time
  • Calculated corrections done by newer analyzers
  • Delta checks
  • Flagging system
  • Numerical and graphical recording
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the three types of histograms used?

A
  • RBC
  • WBC
  • PLT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do RBC Histograms show? What does this coincide with?

A

Normal size (anisocytocis) or any other particles in the RBC size range.

Coincides directly with MCV.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Particles with cell volumes greater than 36 fL are identified as?

A

RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Whay is on the X - and Y - axis of an RBC Histogram?

A
  • X - axis is relative size
  • Y - axis is relative number
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does a normal RBC Histogram look like?

A
  • Almost symmetrical
  • Bell curve with single peak
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Abnormal RBC Histogram:

Shift to the left?

Shift to the right?

A

Left shift = average RBC cell size is below normal (microcytic anemia)

Right shift = average RBC size is above normal (macrocytic anemia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the normal (refrence) range for RBCs?

A

MCV = 80 - 100 fL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does a WBC Histogram enable you to compare?

A
  • A way to compare size and population of patients WBCs with normal population.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

A WBC Histogram is used as a screening tool for what?

A

Used as screening tool to detect hematologic diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

A normal WBC Histrogram will show how many distinct poulations of WBCs?

A

3

  • Lymphocytes
  • Mononuclear cells
  • Granulocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the reference ranges on normal WBC Histrogram for the distinct poulations of WBCs?

A
  • Lymphocytes 35 - 90 fL
  • Mononuclear cells 90 - 160 fL
  • Granulocytes 160 - 450 fL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What other cells may be included in a WBC histogram?

A
  • Blasts
  • other immature cells - promyelocytes and myelocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What information is obtained from a PLT Histogram?

A
  • Size of PLTs
  • Helps identify giant PLTs and thrombocytopenia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What particles are 2 - 20 fL?

A

PLTs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What must be obtained for a valid count in a PLT Histogram?

What are the criteria for a fitted curve?

A

a fitted curve, 0 - 70 fL

  • PLT count above 20,000 microliter
  • Log-normal distribution
  • No PLT count vote-out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What must be done when a fitted curve is not obtainted for a PLT Histogram?

A

A manual PLT determination.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the reference range for RDW?

A

11.5 - 14.5 %

37
Q

What is and how do Cold Agglutinins affect automated cell counting?

A
  • antibodies produced by a person’s immune system that mistakenly target red blood cells (RBCs). They cause RBCs to clump together in cold temperatures.
  • Falsely decrease RBC count and increase MCH (average weight)
38
Q

What is and how does Lipemia affect automated cell counting?

A
  • Excess fat in blood
  • Causes turbidity and falsely elevated Hgb and MCH (average weight)
39
Q

What is and how does Icterus affect automated cell counting?

A
  • Yellow pigentation of body fluids caused by jaundice
  • Causes turbidity and falsely elevated Hgb and MCH (average weight)
40
Q

Where are instrument limitations defined?

A

operations manuals and SOPs

41
Q

What is a common method limitation?

A

Inability to distinguish cells from particles or cells fragments of the same size.

42
Q

Interfering subtances: Variant Hgb / Lysis resistant RBCs

(Variant Hgb can make RBCs resistant to lysis and counted as WBCs)

Affected results?

Indicator?

Corrective action?

A
  • Increase WBC and decrease Hgb
  • Interference with WBC count on histogram
  • Manual dilutions allowing incubation to assist lysis
43
Q

Interfering subtances: Microcytes and schistocytes

What results are affected?

Indicator?

Corrective action?

A
  • Increase PLTs and decrease RBCs
  • Left shift on RBC histogram
  • Examine peripheral blood smear for prescence of abnormal cells and determine correct counts.
44
Q

Interfering subtances: Cold Agglutinins

Affected results?

Indicator?

Corrective action?

A
  • Decrease RBC, Increase MCV, MCH, MCHC
  • Right Shift on RBC histogram
  • Warm blood to 37 degrees if cold agglutinin present
45
Q

Interfering subtances: Significantly increased WBCs (leukemia)

Affected results?

Indicators?

Corrective action?

A
  • Increase Hgb and RBC. HCT incorrect
  • Rule of three violated. WBC count above normal
  • Dilute and do manual cell count
46
Q

Interfering subtances: PLT Clumps

Affected results?

Indicators?

Corrective actions?

A
  • Decrease PLTs and Increase RBCs
  • PLT flag, abnormal histogram
  • Review slide to confirm clumps, warm and agitate specimen to disperse PLTs. Recollect w/ sodium citrate (correct for diltion for multiplying by 1.1)
47
Q

Interfering subtances: Agglutinated RBCs

Affected results?

Corrective action?

A
  • Decrease RBC
  • Review slide for confirmation of giant PLTs. perform manual cell count.
48
Q

Interfering subtances: Giant PLTs

Larger than normal PLT counted as WBC

Results affected?

Indicator?

A
  • Decrease PLT and increase WBC
  • PLT Flag, abnormal histogram
49
Q

Interfering subtances: PLT Satelitetism

PLTs adhere to and surround neutrophils. Caused by PLT cold agglutinins in prescence of EDTA.

Affected results?

Indicator?

Corrective action?

A
  • Decreased PLTs
  • PLT Flag, abnotma histogram.
  • Recollect w/ sodium citrate to rule out reactivity to EDTA
50
Q

Interfering subtances: Increased or abnormal plasma proteins

Lysing reagens precipitate plasma proteins. Precipitates may be counted as WBCs

  • Affected results?
  • Corrective action?
A
  • Increased WBC
  • Hgb x 3 NOT equal th Hct +/- 3
  • Replace plasma with normal saline or perform manual cell count.
51
Q

Interfering subtances: Lipemia and Icterus

Tubidity causes interference with colorimetric reading

  • Affected results?
  • Indicator?
  • Corrective action?
A
  • Increased WBC
  • Hgb x 3 NOT equal th Hct +/- 3, Abnormal histogram
  • Replace plasma with normal saline or perform manual cell count. Cyanmethemoglobin analysis with patient’s plasma as blank.
52
Q

Interfering subtances: Hemolysis

Red blood cells lysed

  • Affected results?
  • Indicator?
  • Corrective action?
A
  • Decreased RBC and decreased Hct
  • Hgb x 3 NOT equal th Hct +/- 3, Abnormal histogram
  • Obtain new specimen
53
Q

What is Reflex testing?

A
  • Machine flags abnormal results
  • Additional testing may be required
54
Q

What are Multivariate checks?

What does it include?

A
  • Interrelations between different tests and the measurements within a test are compared to established limits
    • Review of peripheral blood smear
    • Rule of three
    • correlate erythrocyte indices with automated blood count.
55
Q

Pre-analytical factors?

A
  • specimen identification
  • proper collection methods
  • time
  • specimen integrity
56
Q

Analytical factors?

A
  • Reagents
  • Equipment
57
Q

Post-analytical factors?

A
  • Documentations
  • calculations
58
Q

What are Standards / calibrators?

A

Solutions with a known amount of analyte and used to calibrate a method.

Ex: Hgb standars is 12g/100mL

59
Q

What are Controls used for?

A

Monitor the performance of a method after calibration

60
Q

Who provides performance goals and standards for hematology analyzers?

A

Clinical Laboratory Standards Institute

61
Q

What is Calibration?

A

Established by manufacturer to ensure accuracy and precision.

62
Q

When is an analyzer calibrated?

A
  • Installation
  • Every 6 months
  • Verification:
    • After part replacement
    • After instrument repair
63
Q

True or false: All laboratories must establish/ verify the manufacturer means or “true value” before using a new lot of controls?

A

True

64
Q

How are manufacturer (“true values”) verfied for a new lot of controls?

A

Running 3 control levels each shift, every 8 hours, and/or daily before patient results are reported.

65
Q

Controls must be evaluated daily for? (3)

A
  • Acceptability
  • Ensuring instrument is in good working condition
  • Validating patient results before being reported
66
Q

True or False:

If control is not within acceptable range, patient results cannot be reported?

A

True

67
Q

When would you rerun a control?

A

To verify an error has been resolved. So patient resuls can be run and reported.

68
Q

What are the important components of QC? (3)

A
  • Standards/ calibrators
  • control materials
  • statistics
69
Q

What other times would you run controls? (4)

A
  • New reagent lot #
  • after calibration
  • unusual shift/trend in patient results
  • after maintenance
70
Q

When should a Microcontainer be processed?

A

Within 1 hour of collection

71
Q

How must all microcontainers be checked for clots?

A

With an applicator stick

72
Q

Delays in speciment processing may lead to? (2)

A
  • Falsely macrocytic RBCs
  • Degeneration of WBCs and platelets
73
Q

Prolonged storage in EDTA can cause what in WBCs?

A

Small evenly distributed vacuoles

74
Q

What is the most common method for slide preparation?

What is another method?

A
  • Push-Wedge (most common)
  • Spun
75
Q

What angle is the spreader slide held at for the Push-Wedge Method?

A

30 - 45 degree angle

76
Q

What stain is used in slide preparation?

A

Wright Stain

77
Q

What objective is used to conduct an initial scan prior to performing any specific microscopic examination?

A

10X objective

78
Q

During the initial scan what must the slide be checked/observed for? (4)

A
  • Properly stained
  • even cell distribution
  • platelet clumps
  • Rouleaux formation of RBCs
79
Q

How many fields are scanned of how many cells for RBC morphology?

A

10 oil immersion fields of 200 - 250 RBCs

80
Q

RBC Morphology is evaluated for? (4)

A

Size - Anisocytosis

Shape - Poikilocytosis

Hgb conc.

immature cells (if present)

81
Q

What are the componenents of a WBC differential count? (4)

A
  • WBC Morphology
  • RBC Morphology
  • PLT estimate
  • WBC estimate
82
Q

How many cells are counted in a WBC differential?

A

100

83
Q

When would you correct the Total WBC count?

A

When more than 6 nRBCs are seen in a 100 cell differential.

84
Q

Platelet Estimate: Each PLT seen represents approximately how many PLTs?

A

20,000 PLTs/uL

Platelet Estimate (PE) =

(total # PLTs counted in 10 fields / 10) x 20,000

85
Q

What objective is used for PLT estimates?

A

100X

86
Q

When comparing PE results with automated PLT, if results are significantly different what should you check for?

How is this corrected?

A
  • PLT clumps - invalidate automated count
  • Request new speciment to repeat test
87
Q

What objective is used for WBC Estimates?

A

40X dry

50X oil, if available

88
Q

How many fields are counted in a WBC estimate?

What is the WBC estimate formula?

A

10

WBC Est = average # WBCs x 2000

Hematology MLT (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions