Major lab discloses problem with vitamin D testing

The nation's largest medical lab company says it recently discovered and fixed a problem that led to inaccuracies in a small number of tests for vitamin D deficiency.

Quest Diagnostics of Madison, N.J., notified thousands of doctors in the fall that it had found the problem and then offered free tests for patients whose results were deemed questionable, said Gary Samuels, the company's vice president for communications.

Blood tests to check levels of vitamin D are on the rise because of research showing a possible link between too little of the "sunshine vitamin" and a higher risk of cancer or heart disease.

People normally get vitamin D from exposure to the sun or from fortified milk, orange juice and cereals. It helps build strong bones. But recent research, which still is being debated, suggests it also may play a broader role in protecting against a number of diseases.

"Last year, we did have an issue in a few of our labs that affected a small minority of tests in those labs," Samuels said in an interview this week. "We identified the problem ourselves. We corrected the problem. We notified doctors and other customers and offered free retesting."

Quest, which reported more than $6 billion in sales last year, is the largest provider of medical laboratory tests in the U.S. The company has reported double-digit sales growth for its vitamin D tests in recent quarters. Quest collects medical samples from hospitals, doctors' offices and clinics for tests to diagnose medical conditions. It employs more than 43,000 people worldwide.

Dr. Wael Salameh, a senior medical official with Quest, said internal monitoring picked up hints of a problem during the summer — an "upward trend" in the vitamin D levels being registered by some of its tests.

"That tipped us off," Salameh said.

Eventually, the company flagged about 7 percent of vitamin D testing results from 2007-2008 as questionable, although it believes the problem was much smaller. Generally, the readings obtained on the questionable tests were higher than they should have been, Salameh said. In some cases, though, it was hard to discern a pattern.

Salameh said he doubted that patients would have suffered any harm from the problem. People with serious vitamin D deficiency have physical symptoms such as fractures that their doctors would have noticed. "A good doctor would question the test," Salameh said. "For the few vulnerable patients, other indicators would have flagged the situation to their physician."

Quest officials said the cause of the problem turned out to be the way some of the company's labs were mixing chemicals used in the tests. But the company also is using a new testing technology, which is the subject of sharp debate within the industry. Critics say the method tends to produce vitamin D readings that are higher than warranted.

Aetna, the insurer, said it was notified by Quest about the problem on Oct. 8.

"We did not, however, see any immediate health issues ... that would have required additional action or intervention on our part," spokeswoman Wendy Morphew said in a statement. "We have not received any significant member inquiries on this matter."

New therapy helps boy with rare disease

A drug used to suppress the immune system in cancer and rheumatoid arthritis has helped extend the life of a Minnesota boy struggling with a rare and deadly form of the genetic disorder Pompe disease.

A team of researchers led by Dr. Nancy Mendelsohn of Children's Hospitals and Clinics of Minnesota used a novel treatment plan using Rituxan, or rituximab, a drug used for non-Hodgkin's lymphoma and rheumatoid arthritis made by Genentech Inc and Biogen Idec.

Rituxan is a monoclonal antibody, a genetically engineered immune system molecule. The team used Rituxan in combination with the rheumatoid arthritis drug methotrexate and intravenous gamma globulin, in a bid to damp down the child's immune response.

"It seems to have worked," said Mendelsohn, who chronicled the child's case in the New England Journal of Medicine on Wednesday.

Pompe is an enzyme disease, and many of its youngest victims lack a gene that makes alpha-glucosidase or GAA, which is needed to break down glycogen, a stored form of sugar.

The resulting build up of glycogen damages the muscles, especially the heart and skeletal muscles.

Older Pompe patients often respond to enzyme replacement therapy, but many infants with the "CRIM negative" form of the disease quickly make antibodies to the enzyme and rarely see their first birthday.

Not so for Ira Brown of Minneapolis, whose symptoms first appeared at around five weeks of age.

Stymied by the poor prognosis of infants who develop the genetic disorder, Mendelsohn and colleagues decided to try suppress the child's immune system to allow him to respond to the enzyme replacement treatment.

At 2-1/2, Brown is now the oldest survivor of the CRIM negative form of the disease.

Mendelsohn is hopeful the treatment will induce tolerance to enzyme-replacement therapy, so the Rituxan may one day be discontinued.

She said the treatment approach is being tried on other children and thinks it may work for other diseases, including hemophilia A and B, Gaucher's disease and Fabry's disease.

More 'Screen Time' Linked to Poor Fitness in Girls

Teenage girls who spend more than two hours of "screen time" a day watching TV, surfing the Web or text-messaging are less likely to be physically fit, a new Australian study finds.

Interestingly, boys who were part of the same study were more likely to be able to "sit and be fit," said lead author Louise Hardy, a postdoctoral fellow at the New South Wales Centre for Overweight and Obesity at the University of Sydney.

Boys, particularly older teenage boys, may be less affected by the time they spend watching TV, playing computer games, and other small-screen activities because their growth spurts have led to sufficient muscle mass to maintain fitness and still engage in a large amount of sedentary behavior, the study suggested.

Boys are also more likely to play sports as well as computer games, said Dr. Goutham Rao, clinical director of the Weight Management and Wellness Center at the Children's Hospital of Pittsburgh. An adolescent boy who's on the swim team, for instance, may also spend a lot of time playing a video game like "World of Warcraft," he said.

"There is a culture of physical fitness among boys, and there also is a culture of sedentary activity," he added.

From his experience, Rao said, "there is only a small subset of teenage girls who engage in physical activity regularly." He added that he finds that adolescent girls at his center are more interested in small-screen communication devices, such as texting, than they are in video games.

The Australian researchers said their study may be the first to associate "sedentariness" -- a measure of cardio-respiratory fitness -- with the widely accepted American Academy of Pediatrics' guidelines that children from 2 to 18 years old not spend more than two hours a day on small-screen recreation.

"This is important because ensuring that one has good cardio-respiratory fitness reduces the risk of developing cardiovascular disease," Hardy said. For the study, the researchers measured cardio-respiratory fitness based on the number of laps run at a set pace.

The study, which relied on data collected in 2004, defined small screen activity as watching TV, videos and recreational computer use. The data came from a survey of a representative sample of 2,750 Australian students in sixth, eighth, and 10th grades.

More current data might be even more striking because of the growth of new screen technologies such as XBoxes, PSPs, and Wiis, Hardy suggested. The impact of new small-screen technology may show up in a repeat of the research scheduled for 2010, she said.

The findings will be published in the February issue of the American Journal of Preventive Medicine.

The researchers said the study was limited in its ability to make a cause-and-effect relationship between more small-screen time and less physical activity because other factors might be involved.

The question of whether less physically fit girls are more likely to engage in sedentary activities is one that Rao said he'd like to see pursued in future research.