Question

Question: What is the significance of a lab value's half-life? How would you use that information to assess the lab value?

For example, albumin has a half life of 18-21 days, can someone explain the significance of this and how I would use that information to assess the lab value?

Answer 1

Some proteins are present in the serum are used to measure the malnutrition. The half-life of protein is inversely proportional to the protein concentration in plasma. So, the information of half life is used to assess the lab value to measure the malnutrition.

To understand the proper role of these lab values in the assessment of nutritional status has changed or not, firstly we consider some basic physiology about the protein. Serum albumin protein is the most abundant protein in human blood plasma, it is synthesized in liver and has the longest half-life at 18-21 days. It's half-life is inversely proportional to the albumin concentration present in plasma, it means a decrease albumin content result in increased half-life, and increase the concentration of albumin cause the metabolic rate to increase by upto 50%. The half-life of 18-21 days, is a indicator of dietary intake during the preceding three weeks. Low concentrations of serum albumin (<2.2 g/dl) is a marker of negative catabolic state and the prediction is the poor outcome.

During nutrients deprivation, the protein synthesis by the liver is altered, which result in low serum protein levels. Albumin protein is an important macronutrient for healing woods, supporting immune functions. So it's deprivation cause poor growth and leads to malnutrition. Therefore, serum albumin is the accurate indicator of nutritional status and adequacy of nutritional support.