More than likely, if it was positive when given, it will stay positive even after 4 weeks. I am not sure how long the lab keeps your urine, but most don't take that long before testing.
There is no all-inclusive list of material testing labs in Virginia. Chesapeake Material Testing Labs, E-labs, NanoSafe, and Dominion Engineering are among the material testing labs operating in Virginia.
some labs keep the urine frozen for up to one year but say it depends on what drug their tesetng for. They can keep it in the fridge for 1 week before it is discarded.
WHQL- Windows Hardware Quality Labs testing
One of the most highly regarded test labs is Consumer Reports; they test a wide variety of products on consumer and corporate levels. Independent testing labs for DNA, product nutrition and safety include UL / Underwriters Laboratory, Beackon DNA Testing, Breachway Labs, ParmCo, Atlantis Testing andTestLabs
Some labs do and some labs don't. To be safe, I would assume that they do. It is very easy to distinguish male urine from female urine.
of course
if your a woman you can use male pee, but a man may use woman pee and show up poregnant
Windows Hardware Quality Labs (WHQL) testing
WHQL. Windows Hardware Quality Labs testing and have received the windows logo.
Even the labs used by the courts are private, but certified by the state. Confirm certification before testing. see link
Yes, however to test for heavy metals in the seafood - you'd have to work with a forensics laboratory. Your typical blood labs are for just that - blood (and urine, salivia, etc.), not for any non-human testing
One way is in the use of the animals as test subjects in labs/