QA/QC - Biology
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Quality Control Monitoring QC Data Levey-Jennings Chart +3SD +2SD +1SD Mean -1SD -2SD -3SD 2 Levey-Jennings Chart 3 SD 2 SD 1 SD Mean 1 SD 2 SD 3 SD 3 Monitoring QC Data • Meet pre-established limits, usually 95% confidence interval • Plot Levey-Jennings each day, make decision regarding acceptability • Monitoring over time provides information about the precision and long-term accuracy of measurement • Review charts at defined intervals 4 Control Values and Decision • Consider using Westgard Control Rules • Use premise that 95.5% of control values should fall within ±2SD • Commonly applied when two levels of control are used • Use in a sequential fashion 5 Westgard Rules • 1 2s rule • 1 3s rule • 2 2s rule • R-4s rule • 4 1s rule • 10x rule 6 Westgard – 1 2s Rule • “warning rule” • One of two control results falls outside ±2SD • Alerts tech to possible problems • Not cause for rejecting a run • Must then evaluate the 1 3S rule 7 12S Rule = A warning to trigger careful inspection of the control data +3SD +2SD +1SD 12S rule violation Mean -1SD -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day 8 Westgard – 1 3s Rule • If either of the two control results falls outside of ± 3SD, rule is violated • Run must be rejected • If 1 3s not violated, check 2 2s 9 13S Rule = Reject the run when a single control measurement exceeds the +3SD or 3SD control limit +3SD +2SD +1SD Mean 13S rule violation -1SD -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day 10 Westgard – 2 2s Rule • 2 consecutive control values for the same level fall outside of ±2SD in the same direction, or • Both controls in the same run exceed ±2SD • Patient results cannot be reported • Requires corrective action 11 22S Rule = Reject the run when 2 consecutive control measurements exceed the same +2SD or -2SD control limit +3SD +2SD +1SD Mean 22S rule violation -1SD -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day 12 Westgard – R-4s Rule • One control exceeds the mean by – 2SD, and the other control exceeds the mean by +2SD • The range between the two results will therefore exceed 4 SD • Random error has occurred, test run must be rejected 13 R4S Rule = Reject the run when 1 +3SD +2SD control measurement exceed the +2SD and the other exceeds the -2SD control limit +1SD Mean R4S rule violation -1SD -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 16 17 18 19 20 21 22 23 24 Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 14 Westgard – 4 1s Rule • Requires control data from previous runs • Four consecutive QC results for one level of control are outside ±1SD, or • Both levels of control have consecutive results that are outside ±1SD 15 Control Rule Violations 4-1S 3SD 2SD 1SD Mean -1SD Glucose (Level I) -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Westgard – 10X Rule • Requires control data from previous runs • Ten consecutive QC results for one level of control are on one side of the mean, or • Both levels of control have five consecutive results that are on the same side of the mean 17 10x Rule = Reject the run when 10 consecutive control measurements fall on one side of the mean +3SD +2SD +1SD Mean -1SD 10x rule violation -2SD -3SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day 18 What to do when Control Value is out of limit? • “out of control” • Stop testing • Identify and correct problem • Repeat testing on patient samples and controls • Do not report patient results until problem is solved and controls indicate proper performance 19 Analysis of QC Data Over Time • Levey-Jennings control charts -Gives information about precision, accuracy -Ideally have control values clustered about the mean with little variation in the upward or downward direction • Need to review and document 20 Findings Over Time • Imprecision – large amount of scatter about the mean. Usually caused by errors in technique • Inaccuracy – may see as a trend or a shift, usually caused by change in the testing process, deterioration of reagents etc. • Random error – no pattern. Usually poor technique, malfunctioning equipment 21 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 22 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 23 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 24 1 2s Rule: “Warning” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 25 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 27 1 3s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 28 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 29 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 30 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 31 1 2s Rule: “Warning” Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 32 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 33 2 2s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 34 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 35 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 36 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 37 2 2s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 38 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 39 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 40 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 41 R-4s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 42 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 43 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 44 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 45 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 46 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 47 4 1s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 48 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 49 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 50 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 51 4 1s Rule: “Reject Run” +3SD +2SD +1SD Mean -1SD -2SD -3SD Urea: mg/ dl Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 52 Urea: mg/ dl +3SD +2SD +1SD Mean -1SD -2SD -3SD Level 1 36.98 35.32 33.66 32.00 30.34 28.68 27.02 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Level 2 +3SD +2SD +1SD Mean -1SD -2SD -3SD 54.56 53.04 51.52 50.00 48.48 46.96 45.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 53 Westgard Multirule QC 54
