Prealbumin

Normal: 16 to 40 mg/dL

Physiology:

Thyroxine binding prealbumin, also known as transthyretin, is synthesized by the liver.   Hepatic synthesis is down regulated during critical illness.

Prealbumin has a much shorter half-life than albumin (2 versus 20 days), an attribute that makes it a sensitive marker of acute changes in nutritional status.  When malnourished patients are fed, prealbumin concentrations rise before albumin concentrations do.  Prealbumin is the lab measure of choice for nutritional deficiency screening and for monitoring the efficacy and adequacy of nutritional support.

Low prealbumin levels: Less than 16 mg/dL

Causes:

Prealbumin is relatively unaffected by non-nutritional factors, only severe nephrotic syndrome and high dose corticosteroids can affect reliability.

Assessment:

Hypoprealbuminemia is not associated with specific symptoms or signs.

Labs:

Mild deficit:                12 to 16 mg/dL

Moderate deficit:        7 to 11.9 mg/dL

Severe deficit:                Less than 7 mg/dL (poor prognosis)

TPN correction:

Optimal re-feeding leads to increases of greater than 1 mg/dL/day.  After maintenance rates of TPN are reached, a goal for nutritional support is an increase of at least 3 to 5 mg/dL/week until 20 mg/dL is achieved.

TPN relevance:

Biochemical test that assist the clinician in determining the nutritional  status of the patients,useful for patient assessment and monitoring.It is an indicator of short-term visceral protein status.