QNS is the abbreviation for Quantity Not Sufficient or Quality Not Sufficient. When referring to molecular testing, i.e. nucleic acid or DNA based tests; a final result of QNS is given when the laboratory cannot amplify the submitted sample acceptably.
In the case of insufficient Quantity, this typically means that not enough human cells were collected or submitted in the sample to amplify the internal control for at least a negative test result. The internal control monitors sample collection, as well as sample processing in the lab, to ensure that a false negative report is not issued.
Insufficient Quality can result from inadequate storage or shipping conditions, or inhibitory substances (drugs taken by patient, mouthwash, blood, or other actions taken just prior to collection) which are not removed in routine sample processing, i.e. DNA extraction steps.
Before our laboratory releases a ‘QNS’ report, additional steps are taken to deduce from sample clues what may be preventing adequate amplification of the sample. Steps are taken to remove the potential cause, and the sample is re-tested 1 or 2 times more. If the sample still does not pass the re-test criteria, then a ‘QNS’ report is released.
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