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Red to brown urine: Hematuria; hemoglobinuria; myoglobinuria

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GRAPHICS

DIAGNOSTIC APPROACH

The intermittent excretion of red to brown urine can be seen in a variety of clinical settings [1,2]. The causes of different urine colors are discussed separately. (See "Urinalysis in the diagnosis of renal disease", section on 'Color'.)

The initial step in the evaluation of red to brown urine is centrifugation of the urine to see if the red color is in the urine sediment or the supernatant (algorithm 1).

  • Hematuria is responsible if the red color is seen only in the urine sediment, with the supernatant being clear.

If, on the other hand, it is the supernatant that is red, then the supernatant should be tested for heme with a urine dipstick.

  • A red or red to brown supernatant that is positive for heme is due to myoglobinuria or hemoglobinuria. Rarely, hemoglobinuria is associated with black urine [3,4].
  • A red supernatant that is negative for heme is a rare finding that can be seen in several settings (table 1). These include the use of the bladder analgesic phenazopyridine or a variety of other medications, certain food dyes, the ingestion of beets in susceptible subjects, and porphyria (picture 1). (See "Acute intermittent porphyria", section on 'Clinical findings'.)
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References Top
  1. Rose, BD. Pathophysiology of Renal Disease, 2d ed, McGraw-Hill, New York, 1987, pp. 10-11.
  2. Baran, RB, Rowles, E. Factors affecting coloration of urine and feces. J Am Pharm Assoc 1973; 13:139.
  3. Slotki, IN, MacIver, JE, Mallick, NP, Palmer, HM. Acute intravascular hemolysis with minimal renal impairment in Clostridium perfringens infection. Clin Nephrol 1976; 6:451.
  4. Massoud, OI, Yousef, WI, Mullen, KD. Hemoglobinuria with ribavirin treatment. J Clin Gastroenterol 2003; 36:367.
  5. Pimstone, NR. Renal degradation of hemoglobin. Semin Hematol 1972; 9:31.
  6. Watson, WC, Luke, RG, Inall, JA. Beeturia: Its incidence and a clue to its mechanism. Br Med J 1963; 2:971.
  7. Thompson, WG. Things that go red in the urine; and others that don't (editorial). Lancet 1996; 347:5.
  8. Tunnessen, WW, Smith, C, Oski, FA. Beeturia: A sign of iron deficiency. Am J Dis Child 1969; 117:424.
  9. Eastwood, MA, Nyhlin, H. Beeturia and colonic oxalic acid. QJM 1995; 88:711.
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