Question

You are a lawyer in the courtroom defending your client who was accused of driving under the influence of methamphetamines. A forensic scientist testified in court with the urine analysis of your client post performing a carefully executed ELISA. The scientist explains that the absorbance measured by the experiment is 680 nm and the test was positive because the color of the final solution observed was red. Use your knowledge of science to successfully defend your client.

Answer 1

Firstly before we go ahead and discuss how our client is not guilty we need to understand what is ELISA

ELISA is a test kit which gives preliminary information about the presence of methamphetamine in blood or urine or other body fluids. This system is not completely reliable like GC technique.

In this test the sample from the suspect is taken and entered in the kit and for methamphetamine the absorbance is measured at nearly 450 nm and if the absorbance value is less than the laboratory standard then the sample Is said to be methamphetamine present and if the absorbance is more than the laboratory standard then methamphetamine is absent.

As we can see from the given information that the absorbance was measured at 680 nm which is not ideal for measuring it's absorbance or we can say it's not it's lambda max value.

So this results does not give proper information about the methamphetamine present and hence the client cannot be called guilty untill the test has been performed with more reliable technique like GC or same test with right conditions.

I hope this helps. If you have any query or want more detailed explanation, feel free to ask in the comments section below.