Albumin
What it measures, and what changes the number.
Albumin is the most abundant protein in blood plasma. It is made by the liver and helps hold fluid inside blood vessels while carrying hormones, calcium, bilirubin, fatty acids and many medications. The test measures its concentration in serum or plasma.
It is usually reported with total protein, from which globulins and the albumin/globulin ratio are calculated, and with protein electrophoresis fractions such as albumin %. Total calcium is often read with it because much calcium travels bound to albumin. It also appears on liver and kidney panels.
Hydration affects the number, as does posture and how long a tourniquet stays on, which can concentrate the sample. Labs use different dye-binding methods (bromocresol green or bromocresol purple), and these can give somewhat different results. Units differ too, with some labs reporting g/L and others g/dL. Reports may print Albúmina or serum albumin.
Usually reported in g/L or g/dL.
Often read alongside: Total protein, Albumin/globulin ratio, Albumin %, Calcium (total), ALT
Calculators that use it: Free testosterone calculator