From the Guidelines
Albumin levels decrease during infection primarily due to the body's reprioritization of protein synthesis from albumin to acute phase proteins in response to inflammation, as well as increased vascular permeability and decreased nutritional intake. This shift in protein production is a key aspect of the acute phase response, where the liver increases the production of proteins like C-reactive protein and fibrinogen, which are crucial for fighting off the infection, at the expense of albumin synthesis 1.
During an infection, the release of inflammatory cytokines not only promotes the production of acute phase reactants but also directly suppresses the production of albumin, contributing to its decreased levels in the blood 1. Furthermore, infections can lead to increased vascular permeability, allowing albumin to leak out of the blood vessels and into the tissues, which further reduces serum albumin levels.
In the context of COVID-19, a recent study published in Clinical Nutrition in 2021 highlights that albumin levels are more closely associated with inflammation and poor outcomes rather than serving as a direct indicator of nutritional status 1. The study suggests that hypoalbuminemia, or low albumin levels, may result in interstitial edema, leading to poor outcomes such as tissue damage, delayed wound healing, and impaired GI function, emphasizing the importance of considering albumin levels in the context of the inflammatory response during infection.
Key points to consider include:
- The body's reprioritization of protein synthesis during infection leads to decreased albumin production.
- Increased vascular permeability and decreased nutritional intake contribute to lower albumin levels.
- Albumin levels are a marker of inflammation severity and should be considered in the context of the patient's overall inflammatory status and nutritional condition.
- Infections such as COVID-19 can lead to hypoalbuminemia, which is associated with poor outcomes, highlighting the need for careful monitoring and management of albumin levels during infection 1.
From the Research
Albumin Levels During Infection
- Albumin levels are often low during infection due to increased capillary permeability and escape of serum albumin, leading to expansion of interstitial space and increasing the distribution volume of albumin 2.
- Inflammation associated with infection can also shorten the half-life of albumin, decreasing total albumin mass and leading to hypoalbuminemia 2.
- Hypoalbuminemia is a common condition in critically ill patients, including those with sepsis or septic shock, and is associated with poor patient outcomes 3, 4.
Mechanisms of Low Albumin Levels
- The inflammatory response to infection can lead to changes in albumin synthesis and distribution, resulting in low albumin levels 2, 5.
- C-reactive protein (CRP) levels, a marker of inflammation, have been shown to be negatively correlated with albumin levels, suggesting that inflammation may play a role in the regulation of albumin levels 5.
- The mechanisms underlying the negative correlation between albumin and CRP levels are not fully understood and require further exploration 5.
Clinical Significance of Low Albumin Levels
- Low albumin levels are associated with poor quality of life and reduced longevity, and can interfere with adequate responses to events like surgery or chemotherapy 2.
- Hypoalbuminemia is a general marker of severity of illness, and can be used to guide clinical decision-making in critically ill patients 3.
- However, the use of albumin infusion as a treatment for hypoalbuminemia is not supported by evidence, and management of hypoalbuminemia should focus on correcting the underlying causes of inflammation rather than infusion of albumin 2, 4.