Prealbumin

Introduction

As a nurse practitioner in autonomous practice in Florida, I often encounter patients eager to understand the significance of various biomarkers and how they impact health. One such biomarker that plays a crucial role in nutritional assessments is prealbumin. In this article, we will explore the background, clinical implications, interpretation, and factors affecting prealbumin levels, providing a thorough understanding of its importance in healthcare.

What is Prealbumin?

Prealbumin, also known as transthyretin, is a protein predominantly synthesized by the liver. Unlike albumin, which has a longer half-life of about 21 days, prealbumin has a relatively short half-life of 2 to 3 days. This characteristic makes prealbumin a sensitive marker for detecting acute changes in protein-energy status. It serves important functions, such as transporting thyroid hormones (primarily T4 and to a lesser extent T3) and carrying retinol-binding protein (RBP) bound to vitamin A.

The Role of Prealbumin in Nutritional Assessment

Due to its rapid turnover, prealbumin is often utilized in nutritional assessments to evaluate a patient’s protein status. A decline in prealbumin levels can occur within days if a patient is not consuming adequate protein or total calories. Conversely, levels can rebound quickly when nutritional support is improved. Therefore, prealbumin serves as a reliable indicator of short-term changes in nutritional status, making it a valuable tool in clinical practice.

Understanding Prealbumin Ranges

Prealbumin levels are measured in mg/dL or g/L, with standard ranges as follows:

• U.S. Units Standard Range: 17.00 – 34.00 mg/dL
  
• International Units Standard Range: 170.00 – 340.00 g/L
  
  

It is crucial to interpret these values within the context of clinical findings, dietary history, and other laboratory values, as prealbumin levels can fluctuate due to various factors.

Clinical Implications of Low Prealbumin Levels

Low prealbumin levels can indicate several underlying issues:

Malnutrition or Protein Deficiency

Insufficient intake of protein or total calories can lead to decreased prealbumin levels. This is especially important to monitor in patients who are critically ill, elderly, or have conditions that affect their ability to consume adequate nutrition.

Hepatic Dysfunction

Liver diseases such as Liver Cirrhosis or hepatitis can impair protein synthesis, resulting in lower prealbumin levels. Since prealbumin is produced in the liver, any compromise in hepatic function can have a direct impact on its production.

Chronic Illness or Inflammation

Systemic inflammatory states, such as infections or autoimmune disorders, can reduce prealbumin production or increase its catabolism. As a negative acute-phase reactant, prealbumin levels may fall in response to systemic inflammation or infection.

Renal Insufficiency

In conditions like nephrotic syndrome or other kidney disorders with proteinuria, prealbumin can be lost in the urine, complicating the interpretation of low levels. In some cases of renal failure without significant proteinuria, prealbumin might remain within normal or slightly elevated ranges.

Clinical Implications of High Prealbumin Levels

Although less common, elevated prealbumin levels can also occur and have specific implications:

Rapid Nutritional Repletion

Prealbumin levels can rise quickly in response to improved dietary intake or supplementation. This is often seen in patients receiving nutritional support or those recovering from a period of malnutrition.

Dehydration or Hemoconcentration

Reduced plasma volume due to dehydration can concentrate circulating proteins, including prealbumin, leading to elevated levels.

Corticosteroid Therapy

Exogenous steroids may elevate prealbumin by reducing its breakdown or influencing protein metabolism. This is an important consideration for patients receiving corticosteroid therapy.

Interfering Factors and Drug Associations

Various factors can interfere with prealbumin levels, complicating their interpretation:

Inflammation and Infection

As mentioned, systemic inflammation or infection can significantly impact prealbumin levels. It is essential to correlate prealbumin measurements with inflammatory markers like C-Reactive Protein or ESR.

Hepatic and Renal Function

Given prealbumin’s hepatic origin and potential renal losses, evaluating liver function tests and renal markers (e.g., BUN and Creatinine) is crucial for accurate interpretation.

Drug Associations

Several medications can influence prealbumin levels. For instance, corticosteroids can elevate levels, while other drugs might reduce them. Therefore, a comprehensive medication review is necessary when evaluating prealbumin results.

Conclusion

Prealbumin is a valuable biomarker with significant implications in assessing nutritional status and understanding metabolic changes. Its short half-life makes it uniquely useful for tracking rapid changes, but it also requires careful interpretation in the context of clinical findings, dietary history, and other laboratory values.

As a functional medicine telehealth provider, I integrate evidence-based therapies with IV Therapy to support nutritional optimization and metabolic resilience. Call (904) 799-2531 or schedule online to arrange your personalized assessment.

Further Reading

1. Transthyretin: Its Response to Malnutrition and Stress Injury
   Bernstein LH, Ingenbleek Y. Clinical Chemistry and Laboratory Medicine. 2002;40(12):1344–1348.
   https://pubmed.ncbi.nlm.nih.gov/12556444/
   
2. Prealbumin, Mortality, and Cause-Specific Hospitalization in Hemodialysis Patients
   Chertow GM et al. Kidney International. 2005;68(6):2794–2800.
   https://pubmed.ncbi.nlm.nih.gov/16232252/
3. Plasma Transthyretin as a Biomarker of Sarcopenia in Elderly Subjects
   Ingenbleek Y. Nutrients. 2019;11(4):895.
   https://pubmed.ncbi.nlm.nih.gov/30909154/