The key difference between albumin and microalbumin is that albumin is a protein that is made by the liver and released into the bloodstream, while microalbumin is a very small quantity of albumin that the kidney excretes.
Proteins are important for the health and growth of the cells and tissues of the human body. Measuring the levels of these proteins is very important in the disease diagnostic setup. These tests can help diagnose a number of health conditions, including kidney diseases, liver diseases, and malnutrition. Albumin and microalbumin are two proteins that can be used for the detection of liver and kidney function.
CONTENTS
1. Overview and Key Difference
2. What is Albumin
3. What is Microalbumin
4. Similarities – Albumin and Microalbumin
5. Albumin vs Microalbumin in Tabular Form
6. Summary – Albumin vs Microalbumin
What is Albumin?
Albumin is a globular protein that is produced by the cells of the liver and released into the blood plasma. Albumin has a molecular weight of approximately 66 Kda. Albumin is produced from preproalbumin in the liver cells called hepatocytes. Once the proproalbumin is modified in the Golgi apparatus to form albumin, it is transported out of the liver cells. Then, it is released into the bloodstream. The structure of albumin has several alpha helices bonded together to form the globular protein. Albumin is water soluble and moderately soluble in concentrated salt solutions. Moreover, it experiences denaturation when in contact with heat. Albumin is mainly found in blood plasma. It differs from other blood proteins as it is not glycosylated.
Figure 01: Albumin
Albumin usually carries various substances (cations, fatty acids, hormones, bilirubin, thyroxine, pharmaceuticals, vitamin D, Wnt proteins, and vitamin E) and helps keep other proteins stable. Albumin also regulates oncotic pressure and bone mineralization. Furthermore, doctors can use albumin levels in the blood to help assess liver and kidney functions. It can also be used to evaluate the nutritional status of patients. For example, the albumin level in the plasma is around 4 g/dL. In liver disease, kidney disease, malnutrition, and severe inflammation associated with health conditions like sepsis or burn injuries, this level drops in the blood.
What is Microalbumin?
Microalbumin is a very small quantity of albumin excreted by the kidney. Microalbumin is albumin present in a very small amount of urine. It is measured as part of a test of organ function. Microalbumin has the same properties and functions as albumin. Moreover, the formation of microalbumin is the same as that of albumin. However, microalbumin in urine can be used diagnostically in medicine to detect kidney function. Microalbumin levels can also be used to evaluate fluid balance.
Healthy people excrete a certain tiny amount of albumin (microalbumin) in urine. This amount is up to 30 to 300 mg for 24 hours period. A higher level of this value indicates kidney damage. On the other hand, the low level of microalbumin indicates the person has diabetes insipidus (a problem with the fluid balance in the body).
What are the Similarities Between Albumin and Microalbumin?
- Albumin and microalbumin are two proteins that can be used for the detection of liver and kidney function.
- Microalbumin is albumin that is present in a very small amount of urine.
- Microalbumin has the same properties and functions as albumin.
- The formation of microalbumin is the same as that of albumin.
What is the Difference Between Albumin and Microalbumin?
Albumin is a protein that is made by the liver and released into the bloodstream, while microalbumin is a very small quantity of albumin that the kidney excretes. Thus, this is the key difference between albumin and microalbumin. Furthermore, hyperalbuminemia is due to a high amount of albumin in the blood, while microalbuminuria is due to a moderate excess increase in the level of microalbumin in the urine.
The below infographic presents the differences between albumin and microalbumin in tabular form for side-by-side comparison.
Summary – Albumin vs Microalbumin
Measuring protein levels in the body fluid such as blood and urine has a higher diagnostic value. Albumin and microalbumin are two important proteins that can be used for the detection of liver and kidney function. Albumin is a protein that is made by the liver and released into the bloodstream, while microalbumin is a very small quantity of albumin that the kidney excretes. So, this summarizes the difference between albumin and microalbumin.
Reference:
1. “Albumin.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.
2. “Microalbumin (Urine).” Health Encyclopedia – University of Rochester Medical Center.
Image Courtesy:
1. “PDB 1ao6 EBI” By Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute – (Public Domain) via Commons Wikimedia