Many times we find ourselves dealing with a level of control that just won’t come in, I would like to share some steps that I have applied for many years and is also accepted by regulatory agencies.
Let’s start by asking ourselves, is the control lyophilized?
A. Are we using the correct pipette needed to reconstitute the control?
Serological pipette vs a transfer pipette (it does make a difference). Always check your package insert to ensure you are using the correct pipette. It is necessary to follow manufacturers recommendations.
If the answer to the above question is no then;
B. Ensure that the control is very well mixed prior to use. Testing a sample from an inadequately mixed control will not only give an inaccurate QC result but will also compromise the remaining control in the vial (just because the control is at 2SD does not mean it is in, this is another topic for later on).
Is your control out the first time?
C. Repeat with the same vial of control.
If your control is still out;
D. Open a new vial of control (same lot number) and retest the control. At this point, this is where we are crossing our fingers and hoping for the best.
If QC does not fall with the expected range, there could be;
1. A problem with the lot number if new.
2. Check to see if your lot # is about to expire, or if it has already expired.
3. Check to see if your reagent is at the bottom of the barrel if it is, change it and then repeat control.
4. Review the Levey-Jennings (QC) graphs. Are there any shifts or trends occurring? If yes, the instrument may need to be calibrated. Check the date of the last calibration if due, calibrate.
If not, review the data from the last calibration.
Call your instrument’s technical support to help you review the calibration data, if necessary.
5. Make sure all required maintenance has been performed.
You will be surprised how a simple maintenance, if not performed as scheduled, eventually comes back to bite us.
6. Call the manufacturer if your problem continues, there may be something wrong with the instrument.
7. If no problems are found with the instrument, contact the Quality Control manufacturer or supplier. They may be aware of laboratories having the same problem or they may need to send replacement controls. Be aware, this could mean a different Lot number.
Document all corrective actions taken and communication with suppliers or technical support. Always maintain all your records. You will be surprised how well you will look in your next inspection.
More to come on Quality control. Don’t hesitate to write any questions you may have, we are here to help.