In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. The purpose of this article is to discuss how the structural and presumably functional integrity of albumin, as described by the concept of effective albumin concentration (eAlb), has potentially important clinical implications beyond the total albumin concentration (tAlb) routinely reported by clinical laboratories. Albumin has several functions beyond its oncotic effects, including molecule binding, substance transport, detoxification actions, and serving as an antioxidant. However, there are conformational changes that occur during or following the manufacture of albumin and during its administration to patients with various disease states, such as decompensated liver disease, that often impair these functions. Such impairments are not reflected in tAlb values reported by clinical laboratories and might explain the disconnect often seen between albumin's proposed beneficial mechanistic functions and its less-than-predicted clinical effectiveness as noted in published studies. The concept of eAlb has been introduced to describe albumin with structural and functional integrity. Limited studies have found associations between eAlb values and patient prognostic indicators, but the techniques used to decide these effective concentrations to date are complicated and require specialized equipment and experienced researchers for proper interpretation. Estimation of eAlb may provide valuable information on the functional ability of albumin beyond the tAlb reported by clinical laboratories, but more research is needed to decide how this information is best used in the clinical setting.