Specimen Requirements
Creatinine may be measured using serum, plasma, or urine specimens. Additives such as fluoride and ammonium heparin should not be used due to interference with the method of measurement. Measuring creatinine clearance requires the collection of a 24-hour timed urine specimen and a plasma sample collecting within the 24-hour urine collection period.
Serum or plasma may be tested for BUN. Additives such as fluoride and citrate should not be used due interference with the method of measurement.[1]
Lab Med. 2014;45(1):e19-e20. © 2014 American Society for Clinical Pathology
