omation mbers - Society for Laboratory Automation and Screening

11:30 am Wednesday, February 4 Clinical – Molecular Diagnostic Room C1
Jeffrey Allen
Gen-Probe, Inc.
10210 Genetic Center Drive
San Diego, California 92121
jeffa@gen-probe.com
Process Control With Automated NAAT Systems
Molecular diagnostic assays entering the clinical laboratory are rapidly increasing in number. However clinical
laboratories are experiencing an ever increasing shortage of highly skilled personnel necessary to run these
molecular methods which require significant “hands-on” technique. Automation of nucleic acid amplification testing
(NAAT) offers a solution that simultaneously addresses both increasing testing volume and acute labor shortage.
Yet automation alone is insufficient to address the concerns facing the clinical lab or blood testing facility. For
many laboratories, the quality of the results, i.e., “process control” particularly for NAAT assays, has taken on
greater importance than overall sample through-put. New systems for molecular testing must not only save labor,
but have design features incorporated which provide system performance “checks” throughout the process. While
many clinical chemistry analyzers can determine if sufficient sample volume is present in the primary tube, next
generation platforms must confirm sufficient sample was transferred to the reaction vessel. Molecular techniques
compound the technical challenges in implementing process control, to help ensure quality results, due to the
extreme sensitivities inherent with NAAT and the resulting potential for contamination. Gen-Probe, Incorporated
is currently developing the TIGRIS DTS system which is the first system that not only automates NAAT
procedures, but also provides extensive process control design features (such as: “Reagent Dispense Verification”),
that confirm the assay result integrity. Both hardware and software design features will be reviewed to illustrate
how process control can be implemented with systems capable of detecting less than 100 copies of nucleic acid
target sequence in a clinical sample.
12:00 pm Wednesday, February 4 Clinical – Molecular Diagnostic Room C1
Zhili Lin
Pediatrix Screening, Inc.
90 Emerson Lane, Suite 1403
Bridgeville, Pennsylvania 15017
zlin@neogenscreening.com
113
Co-Author(s)
Joseph G. Suzow
Jamie M. Fontaine
Edwin W. Naylor
Primary DNA-based Newborn Screening of Sickle Cell Disease and Hemoglobinopathy
For a population-based newborn screening program, challenges exist in using technological advances to improve
the quality and efficiency of the existing screening program and to develop new diagnostic capabilities. A newly
developed genotyping method for screening of common mutations within the beta-globin gene is described
here. This genotyping system consists of three major components: an automation system for high throughput
DNA extraction and PCR setup, a conventional thermal cycler, and a LightTyper instrument for post-PCR melting
temperature analysis. Briefly, genomic DNA is extracted from dried blood on a filter paper using the common
chemicals methanol and Tris buffer. Genetic fragments of interest are amplified by asymmetric PCR. Fluorescent
labeled probes are added during PCR setup, which eliminates the need for any post-PCR sample handling
process. Melting temperature analysis is achieved through fluorescent resonance energy transfer (FRET) reaction
using the LightTyper instrument. The assay is designed to simultaneously detect three common beta-globin
mutations, S(A173T), C(G172A), and E(G232A), and can identify any of the eight possible genotypes in a single
reaction: AA, AE, EE, AS, SC, SS, AC, and CC (A represents wild type allele). The method was validated with a
large number of samples in both a retrospective and parallel study. Results were compared to those obtained by
isoelectric focusing electrophoresis. The accuracy of this genotyping method is greater than 99%.
PODIUM ABSTRACTS