1. ABG Instrumentation Analytical Errors

2. Levy-Jennings Chart In Control
+2SD X
-2SD
All values vary about the mean in a regular manner

3. Random Error +2SD X -2SD Only one point fell out of the + range.
Causes:
Statistical probability: rerun control
Sample contamination: repeat analysis on different machine
Sample mishandeling:

4. Random Errors Contributing Factors Corrective Actions
Statistical probability
Contamination of the sample
Improper handling of the sample
Corrective Actions
Reanalyze control sample after performing a 2-point calibration
If this works no further action is needed
If this does not work, follow manufacturer recommendations

5. Systematic or Bias Error Trend
+2SD X
-2SD
Causes:
Contaminated buffers: Perform function check of suspected problem area
Incorrect gas concentrations
Incorrect procedures
Component failure: replace, repair failed component

6. Systematic or Bias Error Shift
+2SD X
-2SD
The plotted points all fall with in the + 2SD range, but the mean value has shifted from where it was at the onset of data accumulation

7. Bias errors Contributing Factors Corrective Actions
Contaminated buffer solutions
Incorrect gas concentrations
Component degradation/ failure
Incorrect procedure
Corrective Actions
Troubleshoot suspected problems
Repair or replace problematic components
Re-run 2 point calibration