New flu tests will speed up detection, CDC says

* New tests will go to state health departments

* New lab will help Mexico test more quickly

WASHINGTON, April 30 (Reuters) - New tests are being shipped to U.S. states that should speed up efforts to screen for the new flu virus that threatens to start a pandemic, health officials said on Thursday.

And a lab with the new test has been set up in Mexico in the hope of finding out how many of the 2,500 suspected cases are in fact the new strain of H1N1 swine flu.

"Now there is a lab that is up and running in Mexico that is able to do diagnoses," Centers for Disease Control and Prevention acting director Dr. Richard Besser told reporters.

Before, Mexico had to send samples to the CDC in Atlanta or a World Health Organization lab in Winnipeg, Canada, meaning a lag of several days.

"This is really a big step. It is going to help us with the studies there. We will be able to confirm cases, the risk factors for those cases. It is going to be very helpful in terms of speeding up the course of those studies."

Besser said the CDC is sending out testing kits to U.S. states that will allow individual state labs to confirm their own cases of swine flu. "We are in the process of rolling out testing capability in every state," Besser said.

The new strain, a strange mix of two swine flu strains with dribblings of genetic material from avian and human flu virus, may have killed up to 176 people in Mexico and a toddler in Texas.

But the symptoms it causes are virtually identical to regular seasonal flu, as well as a host of other respiratory illnesses from the common cold to more exotic coronaviruses.


A quick on-the-spot test can tell doctors if a patient has influenza and some will tell whether it is type A. But more sophisticated tests must be done to show whether it is an H1N1, the type that includes both one of the seasonal influenza strains and the new swine flu strain.

Even further testing will show if it is the new strain, but this requires either a process called PCR, which amplifies and analyzes the genetic material of the virus, or using a test called an antibody test to see if the patient's immune system has mounted a defense against the virus.

"What is being rolled out right now by the CDC is a specific test for this new virus," said the CDC's Dr. Lyle Petersen.

It will fit onto the PCR platform used in state health departments for influenza surveillance and will produce a result in a matter of hours, Petersen said. But it is not something a doctor or clinic can do. "You need a fancy machine to do it," he said in a telephone interview.

For now, the CDC recommends only that people with flulike symptoms who have some kind of recent travel to Mexico or who have been in close contact with a known swine flu patient should get the test.

Petersen said there is a limited amount of material, called reagent, that can be used to make the PCR tests work.

And if the disease is spreading, that will become clear anyhow. "No one is going to recommend doing wholesale testing anyway. If you have a giant outbreak of flu you don't need to test every single person if you know what it is," he said.

Reporting by Maggie Fox, Editing by Sandra Maler