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Improved controls, accurate diagnoses


Bessem Bejjani, MD (left) and Todd Christensen.
Bessem Bejjani, MD (left)
and Todd Christensen.
In today’s advanced health care environment, it’s easy to assume treatments for certain conditions will be available. We even take it for granted that someone will know how to test for a disease in the first place … and give even less thought to the fact that someone first has to figure out how to test the test for the condition we want treated.

Thankfully, lab experts are studying cell mutation, predicting what changes influence what outcomes and determining how the results may or may not point to an accurate diagnosis—all so we can rest assured that our care providers have the necessary information to provide the right treatment.

At Sacred Heart Medical Center & Children’s Hospital, the quality of laboratory tests is taken seriously. With high standards and effective quality control measures in mind, Bassem Bejjani, MD, and Todd Christensen (members of the Molecular Diagnostics laboratory) have pioneered a new way to monitor molecular tests. Their novel approach has captured the attention of laboratories around the world.


Genetic testing at its best
Testing for a particular genetic disorder requires proven controls to be in place. Some disorders may only require looking at one or two cell mutations, but others, like Cystic Fibrosis, can involve testing for dozens.

“That has proved to be a real problem for genetic labs,” explains Todd. “It requires running a control for every mutation. It is really difficult—and really expensive—to find all those mutations and run 32 control samples.”

Todd and Dr. Bejjani came up with a solution. They designed synthetic pieces of DNA for each mutation and put all the mutations into a single control mix.

“It resolves all the mutations in a single reaction—which is really cost effective to run—and gets us back to where we really want to be with every genetic test we want to do,” Todd says.

It may sound simple, but it required months of design work and extensive testing. They started with tapping into public molecular diagnostic databases, querying the system for specific genetic makeup and then designing a sequence that matches the Cystic Fibrosis mutations. Other labs have used similar methods that chop out a piece of a gene and insert it in a vector (a carrier). “That’s really cumbersome,” comments Todd.

What he and his team did that’s novel was synthesizing the DNA sequences with primer binding regions to amplify a gene or specific region for evaluation and end up with millions of segments to look at.

Todd says, “It’s really simple and straightforward, but no one has thought about doing it in terms of creating controls.”

He and Dr. Bejjani were really surprised to discover this technique wasn’t being used anywhere. That has led them to seek a patent for their general methodology.

Going through the long patent process will ultimately protect them from other companies who might re-invent the same thing and then prevent them from using it, says Dr. Bejjani. “Plus, it allows us to generate a cash return to be used for investing in expanded research options.”

The technique they’ve discovered can be applied to evaluating many different types of molecular tests. While Cystic Fibrosis is the most commonly tested, Sacred Heart’s lab also uses the same process for other projects, including the Ashkenazi Jewish panel, which tests for several conditions found primarily in people of Ashkenazi Jewish descent. Their work in this area has attracted the attention of labs in North Carolina, Utah and Toronto.

“We’ve been trying to manage the growth of our control project as much as possible with existing resources,” Dr. Bejjani explains, “but it’s clear we’re going to need funding and more staff.” That, he says, would help them achieve their goal of developing a more systematic approach to quality control that doesn’t exist for molecular testing.

In the meantime, they are well on their way to becoming a primary resource for other labs. They’ve published an article in the Journal of Molecular Diagnostics; and Todd has presented at two national meetings of the Association for Molecular Pathology, plus the EuroGentest symposium on reference materials in Ireland as well.

Despite the complexity of their work, we can all understand that better controls ultimately mean improved care for patients. After all, the more certain physicians are that the lab work is accurate, the more confidence they have in the diagnoses. And of course, better-informed patients are better empowered to face the decisions that lie ahead.


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