Genetic testing emerges

June 1, 2003

Genetic testing is a powerful medical technology that has emerged since the beginning of the mapping of the human genome in 1990. About 50 genetic tests for some 450 genetic diseases are currently available for clinical use. These tests are typically performed on the cells in a blood sample, from which DNA is extracted, and examined for some anomaly that indicates a disease or disorder. Genetic testing is used primarily to:

  • determine if a person is a carrier for a certain disease;
  • determine if a person is genetically susceptible to a certain disease, such as various cancers or heart disease;
  • help predict if an unborn child will have a genetic disease;
  • confirm diagnosis of certain genetic disorders, such as Alzheimers disease.

This month we present a variety of assay, analysis and screening products available for genetic testing.

Genetic image analysis

The Ariol SL-50 system quantifies genetic markers and protein expression through automated image analysis, which characterizes labeled cells through color and morphometric analysis. The system features the companys Ariol software and the SL-50 slide loader, which offers the pathologist high throughput and automated slide scanning for objective and accurate quantification of stained cells. The SL-50 provides system features for case handling, analysis and includes Slide-Link, which enables on-screen viewing and management of multiple sections. The efficiency, communication and productivity of the Ariol SL-50 are appropriate for local and large-scale clinical laboratories, as well as pharmaceutical and proteomic institutions.

Ariol SL-50
Applied Imaging

Gene detection and analysis

The Smart Cycler II enables real-time gene detection with results in as few as 20 minutes. Comprised of 16 independently controlled reaction sites, the Smart Cycler II is a real-time PCR (polymerase chain reaction) system capable of random access. With this capability, end-users can now perform and analyze multiple tests with different experimental protocols and threshold criteria simultaneously or at random intervals on a single instrument. Proprietary microelectronics and optical components enable rapid thermal cycling and real-time fluorometric detection of up to four gene targets in a single reaction tube.

Smart Cycler II

Molecular diagnostic assays

Starfruit GeneTell LIMS (laboratory information management system) features software and database for molecular pathology labs and genetic clinical labs. The system allows labs to manage databases of clinics, hospitals, physicians, samples, tests, inventory, equipment, vendors and reports; track samples from receiving to check-in and -out from storage vault; and order tests and document clinical indications. GeneTell uses a configurable database that records test, disease, interpretation standard templates and cost-per-test data. The system also provides an editor that allows modification of suggestive reports; performs billing, inventory control and equipment maintenance; and documents lab analysis by monitoring PCR from extraction, amplification, genotyping, gel evaluation and restriction enzyme digestion setup. A barcode tracks samples, and a smart card signs electronically.

Starfruit GeneTell LIMS 
Data Unlimited Inaternational

Hybrid capture technology

The Hybrid Capture 2 High-Risk HPV DNA Test (hc2) is an FDA-approved HPV test for primary screening with the Pap test for cervical cancer and its precursors in women age 30 and older, called DNAwithPap. Approved for HPV testing as a follow-up for abnormal Paps in women of all ages, the hc2 is a DNA-based, signal-amplified test with optimized clinical sensitivity, less contamination and is performed in a single work area. RNA probes hybridize to denatured HPV DNA and then are captured onto an antibody-coated 96-well plate. Antibodies conjugated with multiple enzymes bind to the hybrids, producing an amplified chemiluminescent signal when substrate is added. Results are standardized, objective and reproducible. Other hc2 products include DNA tests for chlamydia, gonorrhea and blood viruses.

Hybrid Capture 2 DNA test 
Digene Corp.

Gene expression measurements

GenePaint is a part of the modular Gene Expression Suite designed to automate the study of the function of large numbers of genes simultaneously. GenePaint technology includes all the steps required for performing in situ hybridization (ISH) analysis in cells or tissue samples on microscope slide formats. Automation and liquid handling are combined with a new flow chamber technology to produce a high-throughput system capable of performing all fixing, staining, washing and hybridization processes in a tightly temperature-controlled manner. The system is designed to deliver increased reproducibility for a wide range of gene expression measurements. GenePaint users work in histopathology, cancer research, neurobiology, and cell and developmental biology, with customers working in the areas related to genome projects, expression analysis, functional genomics and current large-scale ISH users.


Nucleic acid diagnostics

The Trugene HIV-1 Genotyping Kit, which runs on the OpenGene DNA Sequencing System, both developed by Visible Genetics, identifies HIV genomic mutations that confer resistance to antiretroviral drugs. Using an algorithm based on expert opinion and clinical research, the Trugene HIV-1 Resistance Report clearly details and interprets the status of a patients resistance to PIs, NRTIs and nNRTIs. The system enables labs to quickly deliver accurate resistance information to physicians, providing them with an important therapeutic management tool. The Trugene HIV-1 system is part of the Nucleic Acid Diagnostics line, which also includes the Versant HIV-1 RNA 3.0 Assay (bDNA) for viral load testing.

Trugene HIV-1 Genotyping kit 
Bayer Diagnostics


A first-generation real-time PCR (polymerase chain reaction) test designed to detect the presence of the SARS (severe acute respiratory syndrome) coronavirus has been developed. The company has begun performing SARS-associated testing to help clinicians diagnose the disease in suspected patients. The detection of the genomic RNA from the SARS coronavirus is based on RT (reverse transcription) of specific viral genomic RNA sequences followed by PCR amplification. A positive RT-PCR result should be interpreted in combination with a patients clinical presentation, along with other diagnostic test results prior to establishing a diagnosis. The company is also offering viral culture test methods capable of growing the SARS coronavirus.

PCR SARS test 
Focus Technologies

HIV-1 fusion inhibitor genotype

To keep pace with the evolution of the HIV drug-resistance challenges, a new test offering for diagnosing Fuzeon drug resistance helps clinicians spot resistance to the newest category of anti-viral targets called fusion inhibitors. The HIV-1 gp41 envelope genotype assay detects and reports all of the major gp41 gene mutations contributing to Fuzeon resistance as reported in the latest scientific and medical literature. The gp41 envelope genotype assay complements the companys current offerings of HIV-1 Genotype and VirtualPhenotype for antiretroviral drug resistance.

HIV-1 Fusion Inhibitor Genotype
Quest Diagnostics

Brad Fitzgerald is associate editor of MLO.
Dr. Robert Nakamura, chairman of the Dept. of Pathology at Scripps Clinic and Research Foundation in La Jolla, CA, assisted with this article.

June 2003: Vol. 35, No. 6

© 2003 Nelson Publishing, Inc. All rights reserved.

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