Veterinary Clinical Medicine-I (General and Systemic)

PHYSICAL EVALUATION OF URINE

Urine volume

• hydration status and renal concentrating ability; it is inversely related to the specific gravity

Urine color

• Normally yellow to amber. Urine concentration will affect the depth of the color.
• Cloudy red urine that clears after centrifugation -hematuria.
• Dark red to brown color -hemoglobinuria or myoglobinuria;
• Yellow-brown, greenish-yellow, or dark brown urine -- bilirubinuria;
• Bilirubinuria also causes yellow-green foam to form when the urine is shaken.
• Pink, blue, or other urine colors may result from some drug therapy.

Urine transparency 

• Clear.
• Semen, mucus, and lipid -turbidity in normal urine.
• Increased numbers of cells, crystals, casts, or organisms -- increase the turbidity of urine in disease conditions.

Urine odor.

• Putrid or ammonia odors -sepsis.
• An acetone odor - ketosis/ ketoacidosis.

Urine specific gravity

• Done using refractometry
• Turbidity of the urine can artifactually affect the specific gravity 
• Normal specific gravity -usually between 1.015 and 1.045, up to 1.065+ in cats
• Specific gravity must be evaluated in light of BUN/creatinine values and hydration status.
• Abnormal substances such as glucose and proteins --- falsely increase the specific gravity.