Ordering an add-on test

An "Add-on Test" is a request to add an additional test to a previously tested patient specimen. 

Sample sufficiency

In some cases, CTGT may not have enough DNA remaining from the previously tested specimen to perform the add-on test. CTGT highly recommends contacting us to confirm that there is a sufficient amount of DNA prior to ordering an add-on test. If an add-on test request is received and there is not enough DNA to perform the test, phone and/or email notification will be provided within 24 hours of receipt of the add-on request. For cases with an insufficient amount of DNA, a new sample is required in order to perform the test.  Add-on tests may be requested for all specimen types, including prenatal specimens.

Requisition form

CTGT does not provide a separate requisition form for add-on tests. To order an add-on test, complete our standard requisition form, including payment information, and note in the “Special Test Instructions” section on the last page of the requisition form that the order is for an add-on test.  Fax the completed requisition form to CTGT at 484-244-2904. 

For institutional billing, CTGT highly recommends that the add-on test is requested through the institutional Sendout Department, which initially sent the patient sample. An add-on test CANNOT be properly processed, if the Sendout Department has not been notified. CTGT will begin testing when a requisition form is received from the Sendout Department. 

Turnaround time

Our standard turnaround times (approximately 1-2 weeks for Sanger sequencing, approximately 2-3 weeks for deletion/duplication tests and 2-4 weeks for NextGen sequencing) also apply to add-on tests.

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