The main difference between albumin and prealbumin is that albumin has a long shelf-life whereas prealbumin has prealbumin has a shorter shelf-life.
Albumin and prealbumin are two types of serum visceral proteins. Traditionally, they are important as markers of the nutritional status of proteins.
Key Areas Covered
1. What is Albumin
– Definition, Features, Function
2. What is Prealbumin
– Definition, Features, Function
3. Similarities Between Albumin and Prealbumin
– Outline of Common Features
4. Difference Between Albumin and Prealbumin
– Comparison of Key Differences
Key Terms
Albumin, Prealbumin
What is Albumin
Albumin is a small protein that makes up more than half of the total serum protein content of the blood. It is produced in the liver. Around 30-40% of the total albumin of the body occurs in the intravascular compartment, while the rest occurs in the extravascular compartment and interstitial spaces. The diffusion of albumin from the serum does not occur freely. Therefore, albumin is critical in providing colloid osmotic or oncotic pressure, which is important in the regulation of the movement of water and solutes across the capillary walls.
Figure 1: Albumin
Inside the vascular compartment, albumin always bears a negative charge due to the presence of Na+ ions. The binding of Cl– ions into albumin increases its negative charge, which in turn, increases the ability to retain more Na+ ions. This increases the number of molecules in the serum, exerting a 50% greater osmotic pressure than it would be by protein concentration alone. In addition, albumin helps in the transport of hormones, bilirubin, vitamins, metals, and drugs. It also facilitates fat metabolism by keeping the fat soluble in the serum.
What is Prealbumin
Prealbumin is a protein made by the liver. It is important for the synthesis of other proteins. In addition to that, prealbumin always carries thyroid hormones in the blood. Moreover, screening prealbumin levels is important for checking the sufficient intake of nutrients to the body. It helps to detect chronic conditions, including infections, trauma, or inflammations. Therefore, low prealbumin indicates that the patient needs a nutritional assessment. Low albumin also reflects the presence of liver disease, tissue death, or inflammation.
Figure 2: Prealbumin
Moreover, high prealbumin reflects chronic kidney disease, alcoholism, or steroid use. Unlike the albumin test, prealbumin test does not depend on the hydration state of the body. More importantly, the shorter shelf-life of prealbumin allows the evaluation of one’s nutritional level. Additionally, prealbumin levels can be obtained from patients 1-2 times a week. Reliable protein improvement may take at least 3 weeks.
Similarities Between Albumin and Prealbumin
- Albumin and prealbumin are two types of serum visceral proteins.
- They are important as markers of the nutritional status of proteins.
Difference Between Albumin and Prealbumin
Definition
Albumin refers to a simple form of protein that is soluble in water and coagulable by heat, such as that found in egg white, milk, and (in particular) blood serum, while prealbumin refers to a protein that is made mainly by your liver.
Importance
Albumin has a longer shelf-life, while prealbumin has a shorter shelf-life.
Nutritional State
Albumin does not make rapid changes in the nutritional state, while prealbumin makes rapid changes in the nutritional state.
Serum Pool
Albumin has a greater serum pool, while prealbumin has a less serum pool.
Conclusion
In brief, albumin and prealbumin are two types of serum visceral proteins that are important as markers of the nutritional status of proteins. Generally, albumin is a simple protein soluble in water. It also occurs in the blood serum. In addition, albumin has a longer shelf-life. However, it does not make rapid changes in the nutritional state. Albumin still has a greater serum pool. In comparison, prealbumin is a protein made by the liver. Prealbumin also has a shorter shelf-life. Therefore, it makes rapid changes in the nutritional state. On the other hand, prealbumin has a less serum pool. Hence, the main difference between albumin and prealbumin is the shelf life.
References:
- Keller U. Nutritional Laboratory Markers in Malnutrition. J Clin Med. 2019 May 31;8(6):775. doi: 10.3390/jcm8060775. PMID: 31159248; PMCID: PMC6616535.
Image Courtesy:
- “PDB 1ao6 EBI” By Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute – Own work (Public Domain) via Commons Wikimedia
- “PrealbuminDimer ribbon” By Jane Richardson – Own Work (CC BY 3.0) via Commons Wikimedia
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