This is taken from the textbook “Urinalysis and Body Fluids” Edition 3 by Susan King Strasinger, D.A., M.T. (A.S.C.P.), published by F.A. Davis Company, Philadelphia, in 1989.
Normal urine gets its color from a pigment called urochrome that is secreted from the body at a constant rate (amount depends on individual metabolism). Because the rate does not change, the intensity in color of the urine can be used for a rough estimate of urine concentration. Very intense yellow color indicates concentrated urine (less water) and very pale or colorless urine is diluted (lots of water). You may notice that your first piss of the day is very yellow, while later pisses are much lighter. This is because your kidneys have been busily excreting all that stuff they usually excrete while you’ve been sleeping and not pissing, so that stuff has built up in your urine (including urochrome), so the first-piss urine is concentrated. While awake you piss regularly, so this concentration doesn’t occur and the urine is diluted and therefore lighter in color. Some urinalyses actually require first-piss samples for accuracy.
Abnormally concentrated or diluted urine can be a sign of a variety of problems, including kidney disease and diabetes insipidus (not the kind that requires insulin).
A dark yellow urine that produces a yellowish foam when shaken may indicate liver problems (normal foam is white). Bright or dark yellow or yellowish-orange urine may also be caused by certain drugs or by eating lots and lots of carrots.
Red or pink urine may be caused by the presence of red blood cells, hemoglobin, myoglobin, or porphyrins. This may also be caused by certain drugs, or, in genetically susceptible persons, by eating beets!
Green or blue-green urine can indicate a Pseudomonas infection, can be caused by certain drugs, or by eating Clorets.
Brown or black urine may be seen in specimens that are left standing for some time if the sample contains red blood cells, denatured hemoglobin, or melanin. Also seen in a condition called alkaptonuria, which basically means ‘alkaline urine’. And, of course, certain drugs can causse the urine to darken after standing.
“Many abnormal urine colors are of a nonpathogenic nature and are caused by the ingestion of highly pigmented foods, medications and vitamins.”
Basically, CowGod, if the above was too much to swallow, if you’re urine is very yellow when you first get out of bed but lighter during the day, you are probably normal (or as normal as a CowGod can be). If your urine stays dark all day long, try drinking more water. Drinking lots of coffee, tea, and dark sodas can also cause your urine to be darker. If you don’t see an improvement after the water increase, see a doctor.
Also, if your urine is colorless or near colorless ALL of the time, see a doctor. It should be darker when you first wake up, unless you piss regularly during your sleeping period. There are several conditions that will result in your kidneys not concentrating your urine, and you should check it out just to be safe.
The woods would be very silent if no birds sang there except those that sang best. - Henry Van Dyke