Multiplex testing through Biochip Array Technology

Biochip Array Technology adds an extra option to diagnostic testing, whether for routine immunoassays, research, clinical trials or DNA screening. Before the introduction of Biochip Array Technology in 2004, diagnostic tests were always performed individually, even though patients usually need a number of different diagnostic tests. Biochip Array Technology allows up to 23 tests to be performed simultaneously using a single biochip, a single sample and a single set of reagents. Randox Laboratories Ltd. has developed Biochip Array Technology from first principles to provide multiple results for the same amount of work as a single diagnostic test.

Biochip Array Technology is a novel technology that is revolutionising diagnostic testing in laboratories worldwide. It is an immunoassay testing platform for the simultaneous multi-analyte assessment of a panel of tests.

Biochip Array Technology combines a panel of related tests on to a single biochip with a single set of reagents, controls and calibrators.

All the tests on the biochip are performed simultaneously in a single procedure using a single undivided sample.

A CCD camera and customised image-processing software simultaneously read the results for the entire panel of tests.

How does Biochip Array Technology work?
Biochip Array Technology is based on proven ELISA principles, a simple and well-established methodology. The innovation of Biochip Array Technology is in simultaneous multi-analyte testing. Each biochip is divided into 25 Discrete Test Regions (DTRs). Each DTR holds an individual test, allowing up to 23 tests to be combined on a single biochip. Two DTRs are reserved for internal quality control, a unique feature of Biochip Array Technology.

A sandwich assay uses antibodies as the capture agents. The antibodies are covalently bound to the Discrete Test Region (DTR) in the correct orientation. Analytes in the patient sample are bound by the complementary antibodies on the surface of the biochip. The enzyme-labelled detection agent binds to the analytes, producing a chemiluminescent reaction that is used to quantify the amount of analyte present in the sample.

Who uses Biochip Array Technology?
There are Biochip Array Technology analysers and biochips for a diverse range of applications including:

• Routine immunoassays with simultaneous multi-analyte testing
• Clinical research such as investigating cytokine levels in inflammatory disease
• Drugs of Abuse tests for forensic toxicology or employee screening
• DNA screening for mutations associated with colorectal cancer

What are the advantages of Biochip Array Technology?

• Accurate results fast, through simultaneous multi-analyte testing
• Provides a “snapshot” of test results from the same sample, reducing biological variation
• Reduced sample and reagent volumes
• Simple sample preparation for the majority of tests
• All the tests on the biochip are performed allowing retrospective analysis

What advantages does Biochip Array Technology have over competitor systems?

• Single analyte systems are generally time-intensive and/or labour-intensive
• Other multi-analyte systems tend to suffer from poor reproducibility or bleeding of DTRs

How many Biochip Array Technology analysers are available?
Evidence is a fully automated analyser designed for high-throughput laboratories. The number of tests on the biochip determines the test throughput.

Evidence Investigator is a semi-automated analyser designed for low-throughput laboratories and research. The Evidence Investigator can also use DNA biochips, for example the RanplexCRC Colorectal Cancer screening test.

Evidence MultiStat provides laboratory-quality patient test results at the point of application in less than 20 minutes. It is an innovation that takes diagnostics out of the laboratory and into areas such as Accident and Emergency, doctors’ surgeries and clinics. Evidence MultiStat will be available in early 2009.

How many biochips are available?
Clinical and research biochips include the Cytokine Arrays, Adhesion Molecules Array, Drugs of Abuse Arrays, Cardiac Array, Fertility Array and Thyroid Arrays. In addition there are biochips for Anti-Microbials, Growth Promoters and Synthetic Steroids. Cancer biochips include the Tumour Monitoring and Tumour PSA Arrays and the RanplexCRC Array for colorectal cancer screening.

Each biochip contains a carefully selected array of tests arranged into disease-orientated test panels, for example the Cardiac Array, or related groups of tests, for example the Drugs of Abuse Arrays.

Can you give an example of a Biochip Array Technology application?
The current test used in the diagnosis of heart attack is a single test, troponin. The latest research indicates that a multi-analyte approach combining two to four tests, including troponin, may have greater clinical utility than troponin alone. Randox’s Cardiac Array combines troponin with other tests such as FABP on a single biochip. This multi-analyte approach is designed to improve the sensitivity and specificity of diagnostic testing for myocardial infarction and acute coronary syndrome. In addition, the Cardiac Array can identify patients with heart attack symptoms that have not actually had a heart attack, enabling Emergency Departments to begin the correct treatment at an earlier stage.

What is in store for the future?
At present each biochip has 25 Discrete Test Regions (DTRs) enabling up to 23 tests to be combined on a single biochip. The size of the DTRs is so small that it is possible to have 100 per biochip, greatly expanding the number of tests performed per sample.

Randox are currently exploring the potential for DNA testing, and the colorectal cancer screening DNA biochip is only the first of many, as DNA testing becomes more commonplace in clinical practice.

Can you summarise Biochip Array Technology in less than 50 words?
Biochip Array Technology is an innovative technology for biochip-based simultaneous multi-analyte diagnostic testing with applications including clinical testing, research, Drugs of Abuse screening and DNA analysis. Biochip Array Technology offers benefits through improving laboratory productivity, reducing costs, improving patient diagnostic information and optimising treatment.

For more information e-mail marketing@randox.com or visit www.randox.com.