Quality

Question 1

primary standard

Answer 1

reference material that has a known amount of analyte and is used for calibrating an instrument or preparing standard curves

Question 2

secondary standard

Answer 2

reference material in which the analyte concentration has been determined by reference to a primary standard

Question 3

calibrator

Answer 3

(in hematology)
a cell suspension whose parameters have been determined by multiple reference labs by reference methods in order to certify their assigned value

Question 4

when are calibrators used in hematology?

Answer 4

to adjust the parameters on the automated analyzer (Coulter/Sysmex)

Question 5

in Hematology, the only CBC measurement that is based on a standard is …

Answer 5

hemoglobin measurement (cyan-methemoglobin std)

Question 6

when are calibrations performed?

Answer 6

• at installation
• routine maintenance (every 6 mos min)
• after the replacement or repair of parts
• when instrumentation drift occurs
• when WC failure occurs with no obvious instrument malfunction

Question 7

how are calibrators different from controls?

Answer 7

used to adjust instrumentation or develop a std curve

Question 8

a control must be: (3)

Answer 8

• similar in composition to unknown samples
• analyzed in the same manner as unknowns going through the entire procedure like unknowns
• stable

Question 9

this is performed on hematology analyers before calibration, every six months, or as needed for troubleshooting purposes

Answer 9

precision checks
- uses a patient sample with normal CBC and diff

Question 10

what is a delta check?

Answer 10

the computer compares current results obtained on a patient with their most recent previous result
- if significantly different= failed the delta check
- check sample integrity, sample labeling, check pt history
- if everything checks, append a comment is appended, and recollection is suggested

Question 11

criticals procedure

Answer 11

1. review testing conditions = no instrument error messages
2. previous criticals?
3. check specimen (clot?)
4. confirm result, if required (ex: manual PLT estimate)
5. verbally report results

Question 12

constant systematic errors

Answer 12

in the same direction and if the same magnitude for all results

Question 13

proportional systematic errors

Answer 13

increase in magnitude as the concentration of the substance being measured increases

Question 14

these result in a loss of accuracy; with a change in mean but not SD

Answer 14

systematic errors
results in shifts or trends on the control chart

Question 15

these are accidental and indeterminate and lack any definite pattern

Answer 15

random errors
- decrease the precision of a method and are indicated by a large SD