Clinical Chemistry 1.2

Question 1

All steps done PRIOR to sample analysis. From test requisition to patient preparation, patient identification, specimen collection, labelling and transport, reception, handling, preparation of processing.

Answer 1

Pre-analytical

Question 2

What are the 5 components in analytical phase?

Answer 2

reagents, preventive maintenance of equipment, calibrator, quality control, and sample analysis

Question 3

Special aspect of analytical testing or laboratory testing

Answer 3

Quality Control

Question 4

include verification of calculations and reference ranges, flagging and not of panic/critical values, delta checks, reporting of results

Answer 4

Post-analytical

Question 5

an algorithm in which a current laboratory result is compared with results on a previous specimen from the same patient

Answer 5

Delta check

Question 6

What is the goal of quality control?

Answer 6

To maintain reliability, accuracy, and precision.

Question 7

Ability to maintain accuracy and precision over an extended period of
time during which equipment, reagents, and personnel may change

Answer 7

Reliability

Question 8

closeness of the result to the true or actual value.

Answer 8

Accuracy

Question 9

the ability to produce a series of results that agree closely with each
other; commonly expressed in terms of coefficient of variation; also
called repeatability or reproducibility

Answer 9

Precision

Question 10

→ Also called Intralab
→ Involves the analysis of at least 2 levels of control every 24 hours
→ Initial control limits are established by analyzing control materials for at
least 20 consecutive days or runs
→ Important for the daily monitoring of accuracy and precision of analytical
methods

Answer 10

Internal QC

Question 11

→ Also called Interlab - Proficiency testing
→ Involves testing blind samples (unknown concentration of analytes) sent
periodically by regulatory agencies to participating laboratories
→ Important for maintaining the long-term accuracy of analytical methods
→ SDI = (Lab Result – Group Mean)/Group SD

Answer 11

External QC

Question 12

the regulatory agency administered by National Representatives (NRs)

Answer 12

National External Quality Assessment Scheme (NEQAS)

Question 13

national reference laboratory for clinical chemistry or biochemistry

Answer 13

Lung Center of the Philippines

Question 14

SDI >2 indicates ______

Answer 14

poor performance

Question 15

An error that is due to chance or an unpredictable cause; does not recur in regular pattern.

Answer 15

Random Error

Question 16

Recurring error inherent in test
procedure; influences observations
in one direction; Recurring error with a predictable
pattern

Answer 16

Systematic Error

Question 17

Random error affects ______; indicated by violation of the 1(2s), 1(3)s, R4s Westgard rules.

Answer 17

precision

Question 18

Affects _____; indicated by shift,
trend, or violation of the 2(2)s, 4(1)s, 8(1)s,
and 10x Westgard rules

Answer 18

accuracy

Question 19

Causes of random error

Answer 19

instrument instability (e.g.
temperature and voltage
fluctuations), dirty glassware,
sampling error, improper mixing of
sample and reagent, operator
variability (e.g. pipetting error),
anticoagulant or drug interference

Question 20

Causes of systematic error

Answer 20

deterioration of reagents,
change in reagent lot, unstable
reagent blanks, calibration error,
changes in standard concentration,
contaminated control solutions,
diminishing lamp power, dirty
photometer, faulty ISE, and pipettor
maintenance error

Question 21

abrupt change in the distribution of control values such that they accumulate on one side or either side of the mean for 6 consecutive days; major cause calibration error/error in standard preparation.

Answer 21

Shift

Question 22

gradual change in the distribution of control values such that they
continue to increase or decrease over a period of 6 consecutive days passing
through the mean; major cause deterioration of reagents.

Answer 22

Trend

Question 23

highly deviating control values caused by random or systematic
errors

Answer 23

Outliers

Question 24

What is the most commonly used QC chart?

Answer 24

Shewhart Levey-Jennings chart (LJ Chart)