Virtually all patients who admitted to an intensive care unit for an extended period receive screening “nutrition labs” to assess nutritional and feeding status.
When using these values to make changes in feeding regimens, the half-life of the substance must be considered to insure sufficient time has elapsed for the result to be a true indicator. Some commonly used substances are:
Albumin – long half-life and used only for overall status and not to tailor feeding regimens on a weekly basis
Prealbumin – commonly used value: half-life is 2 days
Transferrin – 7-10 day half-life
Retinol-binding protein – 10-12 hour half-life