Purple Urine: A Medical Phenomenon

Apr 24, 2025

Purple Urine:
A Medical Phenomenon

Patient Cases

Click the arrow to see the urine samples.

Upon examination, many patients have presented with what appears to be purple urine in their urinary drainage bag.

Of note, the urine is yellow when the bag is emptied.

What is the cause of this urine color?

Patient Cases

Patient Case

Purple Urine Bag Syndrome (PUBS)

Diagnosis

For more on PUBS, visit Figure 1

PUBS is associated with urinary tract infections often occurring in catheterized patients. These patients are generally older adult women with significant comorbidities and constipation.

The urine is usually alkaline. Gram-negative bacteria that produce sulfatase and phosphatase lead to indigo urine staining.