The nurse should obtain the specimen from the catheter.
One of the tests from urinalysis that frequently got contaminated is about infection. The area near the orificium of uretra is near the skin, so there will be microbes around it that can contaminate the sample. The contaminated sample will give a false positive and the result will show the urine are infected.
Taking the specimen from catheter will prevent that contamination, thus giving a better sample.
It's depends on the size of molecule. big ones cannot pass the membrane while smaller molecules can.
B.
H in HF is slightly positive while O in H2O is slightly negative. So they attract in a polar bond. Btw I thought this is chemistry.
<span>Francesco Redi was an Italian scientist, physician, academician and poet. He was the first person to prove that spontaneous generation did not cause the growth of maggots in decaying meat, but they appeared from eggs deposited by flies.</span>
