Porphyrins, Quantitative, Urine
Method Description Describes how the test is performed and provides a method-specific reference
An aliquot of urine is acidified and mesoporphyrin is added as an internal standard. Porphyrins in the acidified urine are separated by HPLC and the eluted porphyrins and internal standard are quantified by comparison of their fluorescence intensity to that of known porphyrin standards. (Ford RE, Ou C-N, Ellefson RD: Liquid chromatographic analysis for urinary porphyrins. Clin Chem 1981;27:397)
Porphobilinogen (PBG) in urine is quantified by liquid chromatography-tandem mass spectrometry after addition of stable isotope-labeled PBG internal standard and solid phase extraction. (Ford RE, Magera MJ, Kloke KM, et al: Quantitative measurement of porphobilinogen in urine by stable-isotope dilution liquid chromatography-tandem mass spectrometry. Clin Chem 2001 September;47:1627-1632)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 7 a.m.