DrBaboon
11-24-05, 14:34
I have reminded myself that there is a lot of bootstrapping in laboratory medicine, and that while immunology/serology has become pretty sophisticated and user-friendly, there are old ways of doing things. AFAIK, these old ways are still taught to medical students and laboratory technology students, but my hunch is that they are not given much thought after training.
Major drawbacks of trying to deal with today's typical serologic kits include: 1) rapidly using them up, and not have anything left to work with; 2) shelf-life; 3) completely dependant on state-of-the-art manufacturing. This next consideration may be more of a US concern, but it's important, too. That is, if you're not working with CLIA waived tests of at most CLIA moderately complex tests, you get into the most heavily regulated laboratory categories to use these technologies.
So where does that leave us in a prolonged austere situation? I suspect that for many of us, the answer has been (and may continue to be) that we won't include serologic/immunologic testing in our repertoire.
Here's where I think this can go, at least as a consideration.
http://web.indstate.edu/thcme/PSP/labtests/precip.htm This is a short & sweet overview that is pretty simplified.
What you're able to say from agar immunodiffusion is that you either have a reaction between antigen in a serum sample and antibody in an anti-serum or you don't. You can also say if you have the same reaction (identity, non-identity, partial identity) between 2 or more serum samples (antigen) tested against an anti-serum (containing antibody).
All you need is agar in a petri dish (or reasonable fascimile), an appropriate anti-serum, and then your serum samples from your patients.
Since we can't obtain specific & identified anti-serum from a manufacturer, we're not going to have a "library" of anti-serums -- IOW what we have won't be a "known" anti-serum that comes with a name of a clinical entity.
However, what I picture doing in the right set of circumstances (such as an epidemic or sufficiently common ongoing illnesses in a community), is obtaining serum samples from people who have either survived/recovered, or are living for a reasonable time after the illness. Those serum samples would be expected to have elevated levels of antibodies directed against the offending antigen.
Our new patients would potentially have antigen in their serum or fluids.
This would probably turn into information that would allow confirmation that the new patient(s) have what the earlier patient(s) had, even if it never gets to the point of giving a name to the exact clinical entity.
Why do this in the first place?
Diagnosis and prognosis are likely uses. It's also conceivable that recognizing that someone does not have the same illness (in spite of possibly similar symptoms) would lead us to treat someone differently. Whether that might lead to changes in general principles of care (precautions, isolation, quarantine, etc) or decisions to use medications (such as committing to use a diminishing supply of antibiotics) is going to depend on the sum of the circumstances.
Whether this could also be used creatively to re-develop serologic testing for syphilis, or potentially such things as rheumatoid factor, is a separate discussion.
The mechanics of doing this test are simple. The mental gymnastics of working through the information and putting it to use are a different matter, and are where I think the challenge lies.
Major drawbacks of trying to deal with today's typical serologic kits include: 1) rapidly using them up, and not have anything left to work with; 2) shelf-life; 3) completely dependant on state-of-the-art manufacturing. This next consideration may be more of a US concern, but it's important, too. That is, if you're not working with CLIA waived tests of at most CLIA moderately complex tests, you get into the most heavily regulated laboratory categories to use these technologies.
So where does that leave us in a prolonged austere situation? I suspect that for many of us, the answer has been (and may continue to be) that we won't include serologic/immunologic testing in our repertoire.
Here's where I think this can go, at least as a consideration.
http://web.indstate.edu/thcme/PSP/labtests/precip.htm This is a short & sweet overview that is pretty simplified.
What you're able to say from agar immunodiffusion is that you either have a reaction between antigen in a serum sample and antibody in an anti-serum or you don't. You can also say if you have the same reaction (identity, non-identity, partial identity) between 2 or more serum samples (antigen) tested against an anti-serum (containing antibody).
All you need is agar in a petri dish (or reasonable fascimile), an appropriate anti-serum, and then your serum samples from your patients.
Since we can't obtain specific & identified anti-serum from a manufacturer, we're not going to have a "library" of anti-serums -- IOW what we have won't be a "known" anti-serum that comes with a name of a clinical entity.
However, what I picture doing in the right set of circumstances (such as an epidemic or sufficiently common ongoing illnesses in a community), is obtaining serum samples from people who have either survived/recovered, or are living for a reasonable time after the illness. Those serum samples would be expected to have elevated levels of antibodies directed against the offending antigen.
Our new patients would potentially have antigen in their serum or fluids.
This would probably turn into information that would allow confirmation that the new patient(s) have what the earlier patient(s) had, even if it never gets to the point of giving a name to the exact clinical entity.
Why do this in the first place?
Diagnosis and prognosis are likely uses. It's also conceivable that recognizing that someone does not have the same illness (in spite of possibly similar symptoms) would lead us to treat someone differently. Whether that might lead to changes in general principles of care (precautions, isolation, quarantine, etc) or decisions to use medications (such as committing to use a diminishing supply of antibiotics) is going to depend on the sum of the circumstances.
Whether this could also be used creatively to re-develop serologic testing for syphilis, or potentially such things as rheumatoid factor, is a separate discussion.
The mechanics of doing this test are simple. The mental gymnastics of working through the information and putting it to use are a different matter, and are where I think the challenge lies.