FUN:BUN RATIO (FILTERED BUN)

Message

Collect venous blood in the serum gel tube. Filtrate specimen should be collected by the nurse at the same time and placed in a sterile tube. Clearly label the filtrate sample as "filtrate. "Additional Information: Both specimens should be sent to the lab together. If both specimens are not collected and sent together the tests will be cancelled.

Test Code

LAB16562 FUN

Alias/See Also

FUN

CPT Codes
84520

Includes

Testing requires both Serum AND Filtrate sample to be submitted to the laboratory at the same time.

Instructions

Processing Instructions (Lab use only): Both specimens should be sent to the lab together.If both specimens are not collected and sent together the tests will be cancelled. Minimum Testing Volume: 0.25mL Serum 0.25mL Filtrate Transport Temperature: Refrigerated Stability: SERUMAmbient: 7 daysRefrigerated : 7 daysFrozen: 1 yearFILTRATEAmbient: N/A Refrigerated : 5 daysFrozen: N/A Causes for Rejection: Unlabeled, mislabeled, wrong tube type, QNS, exceeds specimen stability requirements, one of the two samples are missing/not collected

Clinical Significance

1230130132

Last Updated: May 18, 2026

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.