Responsibility of Accurate Testing

[oldman]

The Responsibility of Accurate Testing - Who is responsible for the testing kits for H1N1, or any other flu for that matter? Time after time, we have all seen reports where the tests came up negative, but a few days later, a child lays dead, a child who was dependent on adults and the medical and scientific community to take care of them. Are the obviously flawed tests a matter of economics? What is the life of a child worth now? How many children must die before someone steps up and says "Hey, these tests do not work so well."? Do we place economics above a child's life now? If so, I want out!!!

oldman

 

[Evelyn]

Re: Responsibility of Accurate Testing

I can't vouch for the ethics of any testing kit manufacturer, but there appears to be genuine extra difficulty in detecting this novel virus. It's not a perfect fit for existing tests, which themselves aren't that great. Could rapid influenza tests be better without raising the cost to prohibitive levels? I don't know. But detecting the presence of a specific virus is a harder task than measuring blood glucose levels, etc. I don't think this is a simple matter of greed or callousness. There are folks here who know a lot more than I do--comments?

 

[Zac]

Re: Responsibility of Accurate Testing

I think the problem with the rapid flu tests is they aren't very sensitive and require high virus titers to ensure detection. The PCR based tests are much more sensitive.

Under the current circumstances, it seems it would be more prudent to dispense anti-virals to anyone presenting with ILI symptoms unless it is contraindicated for some reason. From what I've read, many clinics are only dispensing after a positive on a rapid flu test. With their low sensitivity (average 50%, range 18-69% according to cdc data) and the narrow therapeutic time window of the anti-virals, any delay could be fatal.

 

[Lizw]

Re: Responsibility of Accurate Testing

I can't vouch for the ethics of any testing kit manufacturer, but there appears to be genuine extra difficulty in detecting this novel virus. It's not a perfect fit for existing tests, which themselves aren't that great. Could rapid influenza tests be better without raising the cost to prohibitive levels? I don't know. But detecting the presence of a specific virus is a harder task than measuring blood glucose levels, etc. I don't think this is a simple matter of greed or callousness. There are folks here who know a lot more than I do--comments?

I know very little about how the rapid tests work, so I can't comment on that, but I think the rage here is just as much about what appears to be callous indifference to the patient's condition. The test is negative? Oh, well, there must not really be anything wrong with the child (the child with the 102 deg fever, a hacking cough and severe joint pain). Tell the paranoid mommy to give him some tylenol and send him home. More effective tests may reduce the number of times that happens, but they won't eliminate the attitude that swine flu isn't dangerous, so there's really nothing to worry about.

 

[Zac]

Re: Responsibility of Accurate Testing

CDC rapid flu tests sensitivity data:
(excerpt from CDC director's brief 7/14/09)

 

[Lizw]

Re: Responsibility of Accurate Testing

CDC rapid flu tests sensitivity data:
(excerpt from CDC director's brief 7/14/09)

I see one thing right away--the H3N2 tests have a much higher ratio of correct results than either the seasonal H1N1 or the pandemic H1N1.

 

[AlaskaDenise]

Re: Responsibility of Accurate Testing

..... many clinics are only dispensing after a positive on a rapid flu test. ......

That was my recent experience. They wouldn't prescribe antivirals unless I tested positive. The clinic was completely unaware of the high false-negative rates.

I'll be FAXing them Zac's information.

Are there any new tests on the horizon that have a better sensitivity level?

That would be a best seller.

.

 

[Zac]

Re: Responsibility of Accurate Testing

That was my recent experience. They wouldn't prescribe antivirals unless I tested positive. The clinic was completely unaware of the high false-negative rates.

I'll be FAXing them Zac's information.

Are there any new tests on the horizon that have a better sensitivity level?

That would be a best seller.

.

PCR amplifies (replicates) the virus so it is much more sensitive than the rapid tests. The variations of PCR I'm familiar with use temperature cycling to perform the amplification with each cycle doubling the amount of viral material in the test sample. There are some portable PCR machines, but they're currently still too expensive to be used in a typical clinic. That's unfortunate since the actual cost to build the machines is not that much. (I designed the thermal cycling electronics in the esensor 4800 system when it was made by a division of Motorola--since sold to Osmetech.)

 

[AlaskaDenise]

Re: Responsibility of Accurate Testing

It is so frustrating when a solution exists, but is not at the right place at the right time.

I wonder how the cost of one portable PCR machine compares to the cost of staying in ICU for several days?

.

 

[AlaskaDenise]

Re: Responsibility of Accurate Testing

Here's a portable hand-held PCR machine: http://www.bolinfonet.org/pdf/PortablePCR[2].pdf

the larger version is the size of a laptop computer.

I haven't found the price yet.

here's another one: http://nanofab.caltech.edu/Recent Work/Recent Work Pictures/web-pcr [Compatibility Mode].pdf

It's been tested in Thailand & they claim (slide 14) to have zero false positives and zero false negatives.!!!

.

 

[AlaskaDenise]

Re: Responsibility of Accurate Testing

Here's one with a price!

this does 12 samples, weighs 9 pounds, is 7"W X 14"D X 5" H and.....

It only costs $12,495 - clearly cheaper than an ICU stay.

http://www.spartanbio.com/products/spartan-dx-12/pricing/

Prices calculated in 2005 for an ICU stay were: day 1 on ventilator = $10,794, day 2= $4796, day 3 = $3968.

http://www.ncbi.nlm.nih.gov/pubmed/15942342

.

 

[somebodyoutthere]

Re: Responsibility of Accurate Testing

I thought the CDC said to assume that anyone who presents with ILI has H1N1 at this point.

 

[Zac]

Re: Responsibility of Accurate Testing

There also the cost of supplies. As I recall, a cartridge and reagents for the system I worked on were in the range of $30-70 depending on the type of cartridge and number of active sites. That was nearly 10 years ago. I don't now how this compares with the rRT-PCR used for swine flu testing. The cost of the supplies for each test might be about the same or even more than a course of tamiflu/relenza though.

 

[AlaskaDenise]

Re: Responsibility of Accurate Testing

I thought the CDC said to assume that anyone who presents with ILI has H1N1 at this point.

Depending on which country you're in, the stockpile of Tamiflu varies considerably. I believe the US is on the low end of that scale. Relenza supplies aren't high either. So at some point, they may want to reserve antiviral supplies for known positives, hence the need for reliable testing.

The last I read, Alaska's tamiflu stockpile can only treat (2 pills/day for 10 days) 2% of the population.

If the serious case load gets high enough, there must be rationing, so a good PCR test would make sure the scarce resouces are only used where needed.

.