Visual features


Urine color

The color of the urine sample is assessed subjectively and reported as red, brown, yellow, etc, or combination thereof, along with a modifier for the depth of color, eg, light yellow, dark red/brown, etc. Some examples of various urine colors and corresponding common causes are shown below (this is not an exhaustive list – there are many other substances, including drugs, which can influence urine color).

Color Possible causes
light to medium yellow normal
colorless very dilute urine
very dark yellow very concentrated; bilirubinuria
red to brownish-red hematuria; hemoglobuinuria; myoglobinuria
reddish-brown to brown myoglobinuria, hemoglobinuria, methemoglobin
greenish tint bilirubinuria


Urine turbidity

The turbidity of the urine sample is gauged subjectively and reported using the descriptors: clear, slightly cloudy, cloudy, opaque, or flocculent.

Normally, fresh urine is clear to very slightly cloudy. Excess turbidity results from the presence of suspended particles in the urine. The cause can usually be determined based on the results of a microscopic urine sediment examination.

A sample of turbid urine

A sample of turbid urine

Common causes of abnormal turbidity

  • increased cells (RBC, WBC)
  • numerous crystals
  • bacteria
  • lipiduria (lipids often rise to the surface)
  • mucus (especially in horses)
  • semen
  • fecal contamination