Rapid test helps fight killer bug

By AINSLEY THOMSON

Waikato hospitals are using a new blood test to screen for the deadly meningococcal disease and say it could save lives by producing results in 30 minutes.

This is 24 hours quicker than conventional tests.

The test, which costs $25, is being used to help doctors rule out blood poisoning caused by meningococcus bacteria in patients under 40 arriving at hospital with fevers.

Meningococcal disease is difficult to diagnose because its symptoms are similar to those of influenza.

It has caused more than 200 deaths in the past 10 years, four of them within the past month.

One of these was Wellington woman Nileema Sharan, 25, who died after being wrongly diagnosed and sent home.

Waikato Hospital infectious diseases physician Dr Graham Mills said the blood test made it easier for doctors to determine if a patient had the disease.

The test has sparked interest at the Ministry of Health, and Director of Public Health Dr Colin Tukuitonga says its progress will be watched with interest.

It is about to be evaluated nationally in a six-month trial.

Dr Mills hopes the trial will produce evidence to support the test being used nationally.

He said staff examining patients might miss early meningococcal disease in between 20 per cent and 40 per cent of patients.

"This test will hopefully reduce the misdiagnosis rate to less than 1 per cent."

The conventional test takes 24 hours because cultures from the patients' blood have to be grown.

"And the problem is patients die within 12 hours because the bugs grow faster in their bodies than in the laboratory," Dr Mills said.

The speed at which the disease spreads and the difficulty of diagnosing it have resulted in patient deaths around the country.

One patient whose symptoms were picked up just in time is Te Marena Richards, from Huntly.

By the time the 12-year-old arrived at hospital she had multiple organ failure and was not expected to live.

Two weeks later she is still in hospital on kidney dialysis, but against the odds she is expected to make a full recovery.

Dr Mills said that if she had had the test when she first became ill it would have helped the doctor realise she had far more than the flu.

The technique, known as the PCT test, has been used to check for other bacterial infections.

In June last year it was decided to conduct a trial to see if it could discriminate between patients with meningococcal disease and those with a viral illness.

"We discovered that it was positive for every person with meningococcal disease, and for most people without meningococcal disease it was negative," Dr Mills said.

"If the results are confirmed, it will mean we have a 99 per cent rule-out test - it will be accurate in 99 per cent of individuals."

Dr Mills said the PCT test had enabled the hospital to reduce the amount of antibiotics being given to patients with symptoms of the disease.

This reduced the potential of antibiotic resistance developing.

Like all tests, the PCT process had limitations because it might return positive results when there was no disease, and vice versa.

"But the aim of the test is to aid the doctor.

"It is another piece in the puzzle to continue to lower our death rate as much as possible."

The Associate Professor of Infectious Diseases at Auckland Medical School, Dr Mark Thomas, said Waikato experience showed the PCT test was a useful tool, but it was not the only way to diagnose the disease.

The Waikato research has been submitted to the publication by the Australasian College of Emergency Medicine.