Automation hematology Flashcards

1
Q

BASIC COMPONENTS OF MOST HEMA ANALYZERS

A

Hydraulics, Pneumatics, Electrical systems

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2
Q

Aspirating unit, dispensers, dilutors, mixing chambers, aperture baths, flow cells, hemoglobinometer

A

Hydraulics in HEMA analyzers

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3
Q

Vacuum and pressure systems for operating valves and moving samples

A

Pneumatics in HEMA analyzers

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4
Q

Electrical systems in HEMA analyzers

A

Electronic analyzers, computing circuitry for data processing

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5
Q

ELECTRICAL IMPEDANCE principle

A

Cell counting

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6
Q

Origin of Electrical Impedance

A

Developed by Coulter in the 1950s

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7
Q

Most common methodology for cell counting

A

Electrical Impedance (Coulter Principle)

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8
Q

Radiofrequency (RF) in electrical impedance

A

Modification of DC impedance, measures conductivity, AKA alternating current

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9
Q

Cell counting in electrical impedance is based on the detection and measurement of changes in electrical impedance (resistance) produced by a particle as it passes through

A

Aperture

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10
Q

Impedance change during cell passage

A

Caused by non-conductive particles (cells) in an electrically conductive diluent

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11
Q

Pulse generation in electrical impedance

A

Proportional to the number of cells passing through the aperture

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12
Q

Pulse amplitude in electrical impedance

A

Indicates the cell’s volume

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13
Q

Radiofrequency (RF) in electrical impedance

A

Measures conductivity and changes in RF signal reflect cell interior density

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14
Q

Two-dimensional distribution cytogram

A

Plots RF conductivity and DC impedance of cells

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15
Q

Scatterplot in electrical impedance

A

Displays clusters of cells, representing concentration of a specific cell type

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16
Q

Also known as Electronic Resistance or Coulter Principle

A

Electrical impedance

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17
Q

Instrumental Error: Most common problem in cell counting, produces POSITIVE (+) ERROR

A

Aperture plugs

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18
Q

Instrumental Error: Caused by too vigorous mixing, produces POSITIVE (+) ERROR

A

Bubbles in the sample

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19
Q

Instrumental Error: Produces POSITIVE (+) ERROR

A

Extraneous electrical pulses

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20
Q

Instrumental Error: Produces NEGATIVE (-) ERROR

A

Excessive lysing of RBCs

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21
Q

Instrumental Error: Incorrect aperture current/threshold settings, may cause POSITIVE (+) or NEGATIVE (-) ERROR

A

Improper settings of aperture current/threshold

22
Q

Specimen Error: May be counted as RBCs or WBCs

A

Giant platelets

23
Q

Specimen Error: May be counted as platelets or RBCs, seen in leukemia therapy

A

Fragments of WBC cytoplasm

24
Q

Specimen Error: May cause falsely elevated (↑) WBC counts

A

Some abnormal RBCs (e.g., sickle cells, hypochromic cells, target cells)

25
Q

RBC histogram: RBC count range in fL

A

36 fL to 360 fL

26
Q

RBC histogram curve shift right

A

RBCs larger than normal

27
Q

RBC histogram curve shift left

A

RBCs smaller than normal

28
Q

Bimodal RBC histogram curve indicates

A

Two populations of RBCs (e.g., post-transfusion, cold agglutinin disease, hemolytic anemia with schistocytes, mixed anemias)

29
Q

RBC histogram: Minimum cell size measurable

A

24 fL

30
Q

Cells between 24 to 36 fL in RBC histogram

A

Rejected as RBCs, not included in RBC count

31
Q

Leukocytes in diluted RBC fluid

A

Statistically insignificant, unless leukocyte count is elevated

32
Q

Instrument calibration for leukocytes in RBC histogram

A

Compensates for leukocytes’ presence

33
Q

Effect of significantly elevated leukocyte count

A

Affects the erythrocyte histogram

34
Q

Blood cell histograms y-axis

A

Approximate number of cells

35
Q

Blood cell histograms x-axis

A

Cell size

36
Q

Provide size distribution of the different cell populations

A

Blood cell histogram

37
Q

Provide a count and plot of cells larger than 45 fL in aperture bath

A

WBC histograms

38
Q

Normal first peak (45-90 fL) in WBC histogram

A

Small mononuclear cells (e.g., lymphocytes)

39
Q

Normal second peak (90-160 fL) in WBC histogram

A

Minor population of large mononuclear cells (e.g., monocytes); may indicate abnormal cells in leukemia

40
Q

Normal third peak (160-450 fL) in WBC histogram

A

Normal mature granulocytes

41
Q

Region code (R) flags in WBC histogram

A

Signal irregularities in WBC distribution, appear next to error differential parameters

42
Q

R1 region warning in WBC histogram

A

Increased interference left of lymphocyte peak (approx. 35 fL); caused by sickled RBCs, nucleated RBCs, or giant/clumped platelets

43
Q

R2 region warning in WBC histogram

A

Excessive overlap of cell populations at lymphocyte/mononuclear boundary (approx. 90 fL); caused by atypical lymphocytes, blasts, or plasma cells

44
Q

R3 region warning in WBC histogram

A

Excessive overlap at mononuclear/granulocyte boundary (approx. 160 fL); caused by immature granulocytes (bands, metamyelocytes)

45
Q

R4 region warning in WBC histogram

A

Extension of cell distribution past the upper end of the WBC threshold (approx. 450 fL); caused by very high granulocyte population

46
Q

RM error code in WBC histogram

A

Indicates multiple region overlap

47
Q

H flag in histograms

A

Parameter value is higher than the set normal limit

48
Q

L flag in histograms

A

Parameter value is lower than the set normal limit

49
Q

Platelet histograms derived from electrical impedance method

A

Obtained from volume sizes of 2 to 20 fL

50
Q

Platelet counting in platelet histograms

A

Occurs in the RBC aperture