Luminex (Austin, Texas) reported that it has received FDA 510(k) clearance for a new cystic fibrosis (CF) test: the xTAG Cystic Fibrosis 39 Kit v2, which is designed to detect the 39 CF-causing gene mutations. It is used to screen potential parents to determine if they are carriers of CF mutations, as an aid in newborn screening and in confirmatory diagnostic testing in newborns and children.

This test is actually a new, improved version for Luminex. The first iteration was cleared by the FDA in 2005.

"Compared to the previous version, this is faster and requires less labor," Jeremy Bridge-Cook, PhD, senior VP, Assay Group at Luminex, told Medical Device Daily. "The previous version took about 6.5 hours and this version takes about 4.5-5 hours depending on the model of thermocycler used. And the labor time goes down from one hour and 20 minutes to 50 minutes. The second difference is that the previous versions of the product recommended which enzymes to use, but didn't provide them. In this version, all of the reagents needed are incorporated in the kit."

There are about 70,000 people worldwide who have the disease with 30,000 in the U.S. There is no cure and the median predicted age of survival is 37.4 years, according to the Cystic Fibrosis Foundation (CFF; Bethesda, Maryland).

CF is inherited from parents who carry the mutated genes but are not sick with the disease. It causes mucus to build up and clog the lungs, making it difficult to breathe. That sticky overproduction of mucus can also cause bacteria to stick to airways, leading to infections and lung damage. But the problems with CF don't stop in the lungs. Mucus can also affect the digestive tract and pancreas, wreaking havoc on the body's ability to digest nutrients.

It is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. More than 1,500 such mutations have been identified to date.

Carrier screening is recommended for couples planning a pregnancy as it is possible for a person to carry a CF-causing gene mutation and have no symptoms of the disease. CFF reports that more than 10 million Americans are symptomless carriers of a CFTR gene mutation. Early diagnosis of CF in babies allows for earlier treatment intervention and can help improve a child's long-term health and quality of life.

With no cure in sight, the value of a test can be put to question. But Bridge-Cook said that prospective parents should be tested because, "If both parents have a CF mutation, there's a one in four chance that a baby would have CF. The utility of information in that context is that it enables people to make more informed choices from a reproductive standpoint.

"The other intended indication for the tests is as an aid in diagnosis of newborns," he said. "Babies who are diagnosed early do better and live longer than kids who are diagnosed later. One of the other aspects of CF is pancreatic insufficiency. That condition means babies or young children with CF start to have digestive problems. If its diagnosed early, dietary measures can be taken that lead to much better outcomes and longer survival."

The xTAG Cystic Fibrosis 39 Kit v2 screens for the 23 CFTR gene mutations and four variants (polymorphisms) recommended by the American College of Medical Genetics (ACMG) and American College of Obstetricians and Gynecologists (ACOG), and 16 additional CFTR gene mutations from human blood specimens in a few hours.

The xTAG Cystic Fibrosis 39 Kit v2 offers physicians the ability to select the CFTR gene mutations for which they want to test. Doctors can choose to test a patient for the 23 ACMG/ACOG-recommended gene mutations or the entire panel of 39 CFTR gene mutations.

This newer version of the xTAG Cystic Fibrosis 39 Kit v2 will allow labs to avoid having different platforms for various testing purposes and save time and resources. And like the first generation xTAG CF test, the new xTAG Cystic Fibrosis 39 Kit v2 does not require reflex testing. All results are revealed and available for analysis at each run, if necessary.

Although Bridge-Cook would not discuss the cost of the test, he did say that CPT coding for reimbursement is well established and that the cost of the tests is less than the current reimbursement level, making it "fairly attractive."

Earlier this year Luminex launched the xTAG Cystic Fibrosis 39 Kit v2 and xTAG Cystic Fibrosis 71 Kit v2, as CE-marked in vitro diagnostics under the European Directive on In Vitro Diagnostic Medical Devices. According to the European Cystic Fibrosis Society, as many as one in 30 Europeans are carriers of a CF-causing gene mutation. The xTAG Cystic Fibrosis 71 Kit v2 can screen for all of the genetic mutations in the xTAG Cystic Fibrosis 39 Kit v2 plus an additional 32 mutations including those that are typically found in specific ethnic populations (MDD, June 11, 2009).

Bridge-Cook said a version of the xTAG Cystic Fibrosis 71 Kit is on the way for FDA review and U.S. launch.

Lynn Yoffee, 770-361-4789;