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Hands, urine and stools.
Bacterial contamination will cause no effects if the sample is tested directly after collection. However, if the sample is allowed to sit, bacteria will multiply and raise the urine pH. Urine pH above 8 is abnormal.
Catheter urine is more "sanitary" than regular urine. Because it is collected from the bladder, and doesn't "touch" the external skin, it is less prone to skin contamination.
contamination
Dehydration
what causes inflamation to be in ones urine
The earth's waters continue to see increasing levels of contamination. The main three causes of this contamination is runoff from farms and industry, bacteria, and excess soil.
Insulin affects the concentration of glucose in the urine.
The chemicals in the urine
The most usual cause of blood in the urine is a kidney stone.
Contamination from the genital tract. Another sample should be taken.