Manufacturers of tests used to determine if a patient has the flu say the current outbreak has strained their ability to meet demand from hospitals, medical laboratories and doctors' offices.
Jack Kraeutler, president of test kit distributor based Meridian Bioscience Inc., said the company is running about a week behind in filling orders.
"I don't think that there's a manufacturer or a health professional who hasn't been overwhelmed with how quickly it's moved," Kraeutler said.
The number of states hit hard by the flu has doubled to 24 over the past week and now includes most of the western half of the country. Nationwide, at least 20 children have died in what could become the worst flu season in years.
The diagnosis test involves swabbing a patient's throat and exposing the sample to flu antibodies. If the antibodies attack the sample, a color or pattern shows up to indicate the person has the flu.
The tests are considered a reliable way of detecting which strain of flu a patient has, said Kristopher Weiss, spokesman for the Ohio Department of Health. Determining the strain helps doctors figure out the appropriate treatment, he said.
An early diagnosis can help a doctor determine whether to recommend that the patient stay home and avoid spreading the flu to others in offices or schools, churches and day care centers, Kraeutler said.
"If you've got a definitive diagnosis, it's good for controlling spread of the infection in the population," he said.
The Baltimore-based BD Diagnostics Systems, which also manufactures the kits, said it already has received as many orders as the company got last year for the entire flu season. The season, which generally begins in late December and ends in March, started earlier this year.
"We are working around the clock right now, 24 hours a day, seven days a week," said Michael Meehan, president of BD Diagnostics Systems. "As fast as we can make them, they're being ordered and shipped. There's a lot of testing going on out there."
About two million flu tests are done nationwide during a typical flu season, but that number could be exceeded in this season, Meehan said.
Quidel Corp., which is based in San Diego, has increased its production of flu test kits to 24 hours a day, seven days a week to accommodate the heavy demand, said S. Wayne Kay, president and chief executive officer. He declined to say how many flu tests his company sells.