What is the main purpose of testing for serum prealbumin?

Testing for serum prealbumin primarily serves to indicate compromised nutritional status. Prealbumin, also known as transthyretin, is a protein synthesized by the liver and is involved in the transport of thyroid hormones and retinol. Its levels in the serum can reflect a person's nutritional state more sensitively than other proteins, such as albumin, because it has a shorter half-life and responds more quickly to changes in dietary protein intake.

When an individual has a compromised nutritional status, prealbumin levels tend to decrease. This makes serum prealbumin an important biomarker in clinical settings for assessing nutritional issues, especially in patients at risk of malnutrition, such as those with chronic illness, post-surgery, or in critical care settings.

The other options may involve testing for different reasons: liver disease would be assessed using other liver function tests and specific enzymes; infections would typically require different markers such as CRP or specific pathogen tests; and kidney function is usually assessed through creatinine and blood urea nitrogen (BUN) levels, rather than prealbumin. Thus, while the other options are important for different clinical assessments, they do not utilize serum prealbumin as the main indicator.