Hot Topic

Specimen Source Required for Microbiology Tests


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Published: January 2012

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Proper specimen collection is a critical step in laboratory testing success. However, when a specimen arrives without the specimen source, it's impossible to determine if the specimen is correctly collected, if the test ordered is appropriate, or if the results are logical and accurate.

Presenter: Robin Patel, MD

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Welcome to Mayo Medical Laboratories' Hot Topics. These presentations provide short discussions of current topics and may be helpful to you in your practice.

Our presenter for this program is Dr. Robin Patel, the Chair of the Division of Clinical Microbiology and a Professor of Laboratory Medicine and Pathology at Mayo Clinic in Rochester, Minnesota. Dr. Patel discusses the importance of identifying the source of the specimen and upcoming changes to the testing protocol. Thank you, Dr. Patel

Thank you, Sharon, for that introduction. This presentation is on why the specimen source is required for microbiology tests.

Specimen Source

The specimen source is required for preanalytic, analytic, and postanalytic or reporting processes.

Why is this important?

Why is this important? For cultures, the specimen source helps us determine whether the specimen is acceptable for the requested culture. We look at the location from which it was collected, whether it is of sufficient volume, whether the correct transport media and temperature were used, for example. It is also important because it helps us determine which culture media are required, which organisms should be identified and reported, and finally how the report will be issued including whether the results would qualify as critical/semi-urgent or reportable diseases.

This is also important for PCR testing. For PCR, the specimen source is used to determine whether the test is validated for the specimen source, whether the specimen received is acceptable for testing (for example, whether it is of correct volume, whether it is in the correct transport media, and whether it was transported at the correct temperature), and also whether preprocessing is required.

Consequences of Specimens Arriving without Specimen Source

There are consequences of specimens arriving without a specimen source. These include delayed results, specimen degradation resulting in poor quality results, the potential for the specimen to be misplaced while awaiting additional information regarding the specimen source, specimen rejection when the specimen is beyond its validated time limit for testing, and finally, provider, client, patient dissatisfaction.

Unacceptable Specimen Sources

Some of the types of unacceptable specimen sources that we receive include specimens labeled as other, unknown, SNS, or I don't know. In addition, if specimens such as fluids, wounds, swabs, or tissues are submitted, we request that the anatomic location from which they were collected be specified.