Antibiogramm

An Antibiogramm comes second. The laboratory first identifies the pathogen in the sample, and only then tests that pathogen against a panel of antibiotics to see which of them still stop it. The identification answers what the infection is. The Antibiogramm answers what is likely to work against it, and those are two different questions that arrive at two different times.

Resistance is the reason the second step exists at all. The obvious substance is no longer reliably the working substance, and for a given isolate the only way to find out is to put the candidates against it and read what happens. That is also why the answer cannot be looked up in advance from the name of the organism alone.

The timing follows from the method. Something has to grow before anything can be read, so an Antibiogramm takes days rather than minutes and it can never be a Point-of-Care-Test. When a customer asks at the counter why the result is not back, the honest answer is that a culture has to grow first and that no amount of pressure shortens it.

Everything before the laboratory still decides the outcome. A urine sample kept warm grows the wrong organisms and a swab that dries out grows nothing, which puts the result in the hands of Präanalytik and Probenlogistik rather than of the analysis. The akkreditiertes Labor states the container, the temperature and the transport window for each sample type, and those instructions are not open to local improvisation.

The boundary here is unusually clean. An Antibiogramm describes what happened in a laboratory dish under laboratory conditions. Which antibiotic a person should take, at what dose and for how long, is a prescribing decision that also depends on the person in front of the prescriber, so the report belongs to the prescriber. A pharmacy team can explain what the report is for and why the wait was necessary. Reading a recommendation out of it is somebody else's work.