Title

When equipment appears to be defective, determine and correct the potential negative influence on previous testing results

Why

Equipment that is defective may produce results that are incorrect. When this defect goes unnoticed the laboratory may report incorrect test results without knowing it. E.g. when the filter of a spectrophotometer is defective, the machine could still produce an optical density value. It can take a while before it is noticed that the filter is defective. Hence, all the examinations done in the period in which the filter was broken may be incorrect. It is crucial that the patients for which wrong results may have been reported are traced for retesting.

What

Write a procedure on determining and correcting the potential negative influence on previous test results when a piece of equipment has been functioning incorrectly. Include this procedure in the SOP for Equipment Repair. In general, the following steps have to be undertaken:

  • When a piece of equipment appears to be defective, take it out of service and arrange for repair (see activity on developing the SOP for Equipment Repair).
  • Estimate to what extent the defect could have influenced the outcome of testing.
  • Determine whether it is necessary to retest the samples that have been analyzed using the defective piece of equipment.
  • If retesting is needed: attempt to determine since when the piece of equipment started to function incorrectly.
  • Trace the samples that have been analyzed using the defective piece of equipment in the laboratory.
  • If the samples are not stored in the laboratory, try to contact the clinicians/patients for which these samples were tested. Determine whether the condition of the patient necessitates retesting. If the patient has not recovered from disease, ask him/her to supply a new sample to the laboratory for retesting.


Including a form in the SOP for Equipment Repair can be convenient. This form can for example be routinely used to report defective equipment to the Equipment Officer. Guidelines should be printed on the form that direct the Equipment Officer to start the procedure of determining and correcting the negative influence of defective equipment on laboratory testing.

How & who

Laboratory Manager:

  1. Write the procedure for determining and correcting the negative influence of defective equipment on test results and add this to the SOP for Equipment Repair.
  2. Review and authorize the SOP in accordance with the SOP for Document Control.
  3. Include the SOP in the Read and Understand List and indicate the staff members who have to read the SOP (those for who this SOP is relevant).
  4. Present the SOP to all the staff members and explain the reason why it is important to determine the potential negative influence of defective equipment on laboratory testing. Indicate which staff members have to read the SOP and explain that they have to sign the Read and Understand List when they have read the SOP.

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This activity belongs to the QSE Equipment

 

ISO15189:2007: 5.3.7
ISO15189:2012: 5.3.1.5
ISO15190:2003: