The appearance of a dark-reddish urine is suggestive of a number of conditions, including hematuria; however, there are no red blood cells present on microscopic examination. Fuhermore, the dipstick test for blood is positive, which is suggestive of myoglobinuria. Myoglobin is a pigment that, if present in the urine, will produce a positive dipstick test, even in the absence of red blood cells. Myoglobinuria can be caused when an unconditioned individual paakes in intense physical exeion. This extreme physical activity leads to muscle cell breakdown and the release of myoglobin into the blood, which is then filtered by the kidneys and excreted into the urine. If there was hemolyzed blood in the urine , a few red blood cells should have been detected on urinalysis. Ingestion of foods that contained red dye can discolor the urine; however, it would not produce a positive dipstick test. Nephrolithiasis generally results in the appearance of blood cells in the urine. Ref: Kennelly P.J., Rodwell V.W. (2011). Chapter 6. Proteins: Myoglobin & Hemoglobin. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.