I would suggest seeing a physician. Any time there is "dark urine" it may be suggestive of blood. The only way to tell would be to perform a urine dip or urinalysis by your physician.
Infections, such as a UTI or prostate infection, can lead to this. Various types of cancers - such as prostate cancer or bladder cancer - also should be considered.
If there is no blood in the urine, various types of kidney disorders as well as an elevation in the body's bilirubin can lead to dark urine as well.
You may wwant to discuss these options with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b