Considering Common Factors on Multitest Systems

If a multi test system is in use, there may be a problem with a single test or with several tests.

• One test involved

  Apply the first two steps (for example, determine the type of error and relate it to possible causes).

• Several tests involved

  Consider what, if anything, the tests have in common. Ask the following questions:

  • Do all the tests have small or large sample sizes?
  • Do all the tests use the same filter?
  • Do all the tests with the problem use the same lamp and tests without the problem use a different lamp?
  • Do all the tests use the same mode of detection (for example, endpoint versus rate, MEIA versus FPIA)?
  • Do all the tests have certain mechanical components in common or certain optical components in common?