Creating a Molecular Atmosphere, Phase 5

Abstract

As mentioned in previous articles in this series, product inserts are available with most FDA-approved assays. These product inserts contain information about the product as well as explain processes and procedures approved by the manufacturer of the assay. Included in these procedures are quality control (QC) recommendations. Some FDA-approved assays have QC material included in the packaging of test materials; others suggest from whom to purchase the quality control material and provide recommendations on how to use it. For all of the assays that we perform on the Infinity (Thermo Fisher Scientific, Waltham, MA) instrument, we routinely perform external QC on new lots and new shipments. All of these assays are FDA-approved, qualitative, and include a built-in internal control for every patient test that is performed. Because the internal control is present, we are not required to perform external QC procedures with every patient specimen. The external controls used for these assays are purchased from a manufacturer and can be used directly or after a simple dilution is made. The assays we perform on the SmartCycler (Cepheid, Sunnyvale, CA) are laboratory developed; therefore, control materials are not commercially available in ready-to-use form. Clinical Laboratory Standards Institute (CLSI) and College of American Pathologist (CAP) guidelines suggest that laboratorians ensure that a control is present throughout the entirety of a patient testing procedure. If an internal control cannot be present from start to finish, external-control material must be included in every patient-testing procedure. For herpes simplex virus (HSV) external control, we purchase stock virus from a manufacturer. We grow the virus in shell vials, in a similar manner that we would use for controls when setting up HSV cultures. This growth of virus in shell vials takes anywhere from 3 to 5 days to yield a 90% or greater cytopathic effect (CPE). … [↵][1]* To whom correspondence should be addressed. E-mail: stephanie.e.wallace{at}osfhealthcare.org [1]: #xref-corresp-1-1