Ebola testing

What tests are hospitals using to diagnose ebola? How long do they take? What is their accuracy? Are they in-house? I wanted to focus on what test will be deployed in developed world on suspect cases.

Sorry posted this before I read your second post, so you may be looking   for more specific information on time frames in your region of US. No matter what the testing method is the same.

Diagnosis is done by PCR and if a lab has primers can be completed in approx 2 hrs. However waiting times can be greatly increased as follows.

1) Time to get sample to testing centre. Delays when testing centres are far from patients. There are only 3 in Liberia. In UK most testing is done at Porton Down military lab, though Glasgow and London also have licences lab. As in US and rest of Europe the transportation of such biological samples is really complex,so in West Africa rural roads are the problem, in Europe and US it is paperwork.

2)Cost counts. If finances are short they have to wait to batch samples which is more cost effective. ( like waiting on a fairground ride they won't start the ride until there are X amount of people on the seats). Biotech companies put up prices of primers etc when demand is high. This won't be of concern in US.

3)Need to retest. In UK if someone were to be tested and it came back negative, they have to wait 4 days in isolation to be retested. Just incase viral load in blood was too low at initial presentation.

4) I am sorry I do not know the false positive and false negative rates. It depends on affinity of primers, concentration of virus in blood, control sample purity etc. Perhaps someone else knows this data, sorry.

Two other points. A recent nature article by a Dr J D Kelly urges the need to make diagnostic centres a priority for Ebola crisis

Quote:
Bottlenecks in testing samples for Ebola leave patients stranded for days in isolation wards and raise fears of seeking treatment.

Heres his account of before and after.

Quote: The evening the curled man arrived at Connaught, there was no nursing staff to oversee patient care. The Sierra Leonean doctor who had supervised the ward had died, and no Sierra Leonean doctor had taken his place. The man was locked in this terrifying environment until someone could draw his blood for testing. Blood samples and sick patients were sent to Kenema by ambulance only at the end of each day. Even after the man’s blood sample arrived in Kenema, it was not tested until the next day.

Then later in the article he says

Quote:
Take Freetown, for example. A four-person team from South Africa arrived there on the same flight that I did. They came with a machine for analysing viral RNA and created a diagnostic site in the outskirts of Freetown at the National Laboratory of Sierra Leone. Within a week, the team was sending Ebola test results to the isolation ward twice a day. Some patients did not even have to stay overnight. That kind of experience feels less daunting and more acceptable

The last point to mention is that there is a rush on to make rapid tests that are able to be used in more rural places. This is one developed in Japan this month.


Ebola Outbreak: Japan Develops 30-Minute 'Simpler' Test To Quickly Diagnose Deadly Virus

Japanese scientists said Tuesday that they have developed a Ebola test that could detect the Ebola virus in 30 minutes, with the help of a technology they claim is faster and cheaper than the current method being used in West Africa. More than 1,550 people have so far died from the current Ebola outbreak and over 3,000 have been infected.

Eiken Chemical Co., along with researchers at Nagasaki University, reportedly created the new testing method, which can be conducted with a “small, battery-powered warmer,” making it ideal for use in places without an adequate power source, the scientists claimed. The current test requires “dedicated equipment and a stable supply of electricity,” according to a local report.

"The new method is simpler than the current one and can be used in countries where expensive testing equipment is not available," Jiro Yasuda, a professor at Nagasaki University, told Agence France-Presse, or AFP. "We have yet to receive any questions or requests, but we are pleased to offer the system, which is ready to go," he reportedly said.

Yasuda and his team at the university have reportedly created what they called a "primer,” which magnifies only those genes specific to Ebola found in a blood sample or any other fluid in the body. If Ebola is present, the action of the primers distinguishes DNA specific to the deadly virus in 30 minutes.

Currently, a technique called polymerase chain reaction, or PCR, is being used to detect the Ebola virus. The PCR method takes up to two hours as doctors need to heat and cool the blood samples repeatedly to complete the procedure.

"The new method only needs a small, battery-powered warmer and the entire system costs just tens of thousands of yen [hundreds of dollars], which developing countries should be able to afford," Yasuda said.

http://www.ibtimes.com/ebola-outbreak-japan-develops-30-minute-simpler-test-quickly-diagnose-deadly-virus-1675502

Anyway hope this answers something.

Hzx

2 to 3 hours once in lab, depending on annealing temperatures of primers.

However even within hospitals you not allowed to send samples by the tube systems, which are often used ( samples can break in pipes). Also not allowed routine porters to handle Cat4 samples ( samples go missing all the time). So even getting sample across a hospital full of public to the site of lab can be delayed. Lastly reporting of such important results won't be by testers, head of department would have to sign off and issue results.

Guess this can delay results. They may also want to repeat, or do further testing.

Even if negative they would still deep clean room, as patients can turn positive the next day or so.

Hzx

Testing results on Marine Phoenix sailers seemed to be released pretty quickly as well. I have been curious what time frames were reasonable. At some hospitals reporting such testing taking much longer.

I thought that seemed fast for a test. As it appears a test was not done.

http://www.cbc.ca/m/touch/canada/story/1.2774676

The ward was later reopened after a closer look at the itinerary showed the patient was not in the same region as the outbreak. Health officials will not be testing the patient for the virus.

So why haven't they released test results on Dallas County Sherrif Dept. Employee???