Levey - Jennings Plot

Question 1

Suggests a systematic drift or error

Answer 1

Trend

Question 2

Values move continuously away from the mean in just one direction

Answer 2

Trend

Question 3

Causes of trend

Answer 3

deteriorating reagents, changes in standard concentration or failing instrument

Question 4

Also suggests systematic error

Answer 4

Shift

Question 5

Seen as an abrupt change from the established mean and continues in a linear fashion parallel to the mean.

Answer 5

Shift

Question 6

Suggests random error.

Answer 6

Increased dispersion

Question 7

High or low outliers are frequently observed

Answer 7

Increased dispersion

Question 8

Causes of increased dispersion

Answer 8

variations in operation of instrument,
interfering substances,
electronic fluctuations, and
clerical errors.

Question 9

One control observation exceeds the control limit set at
M土2SD

Answer 9

1:2s

Question 10

1:2s suggests

Answer 10

Warning rule

Question 11

Reject when one observation exceeds M土3SD;

Answer 11

1:3s

Question 12

1:3s suggests

Answer 12

Random error

Question 13

Reject when two consecutive observations exceed the same M+2SD or the same M-2SD

Answer 13

2:2s

Question 14

2:2s suggests

Answer 14

Systematic error

Question 15

Reject when one control observation in the run exceeds its M+2SD and another exceeds M-2SD

Answer 15

R:4s

Question 16

R:4s suggests

Answer 16

Random error

Question 17

Reject when four consecutive control conversations exceeds the same M+1SD limit or the same M-1SD limit

Answer 17

4:1s

Question 18

4:1s suggests

Answer 18

Systematic error

Question 19

Reject when 10 consecutive control observations fall on one side of the mean

Answer 19

10:Mean

Question 20

10:Mean suggests

Answer 20

Systematic error