- Cell culture--grow the cells in a Petri dish, look at them under a microscope. Length: a matter of days. Easiness: if you can handle a cotton swab without putting it in your ear, you can do this. Reliability: only for those organisms that can be cultured--there's a good chance that we can culture only about 2% (some say more) of the bacteria we know about; some just don't grow outside their native environs. Price: very cheap, as long as you have a decent microscope and a bit of agar.
- Looking at molecules--take some DNA from the patient's sputum (or whatever the organism is likely to inhabit), compare it with DNA from known bugs, make a diagnosis. Length: several hours. Easiness: difficult because of the technology involved. Reliability: "Able to detect specific strains of organisms, so treatment options are more effective." 'Nuff said. Price: Very 'spensive.
- Immunoassay--test for antibodies. Length: minutes, usually. Easiness: It's in home pregnancy tests, among other things, so 'even a woman can do it.' Reliability: "Generally not as sensitive as DNA-based tests." Price: fairly cheap.
Tuesday, February 5, 2008
As I mentioned in a previous post, scientists are very eager to develop tests that detect MRSA faster. It looks like there may be some coming up after all (D1, subscription required). Surveyed in the article are three types of tests; here they are in order of increasing quickness (but not necessarily easiness, reliability, or price):