Which albumin should we measure?

Albumin circulates in the blood as a single homogeneous protein. During passage to the urine it can undergo configuration and digestive change, producing moieties not equally detected by the various methods currently routinely used for quantifying albuminuria. In normal urine, albumin is not the most common protein. In microalbuminuric states, detection techniques of great sensitively and specificity are required, looking for the whole molecule, immunoreactive moieties, peptide fragments, or all of these. We are unsure of the most accurate technique in terms of patient prognosis; accordingly, we must now ask "Which albumin should we measure?"