What is the Difference Between C-reactive Protein and Creatinine

The key difference between c-reactive protein and creatinine is that c-reactive protein is a ring-shaped pentameric protein produced by the liver and found in blood plasma, while creatinine is a non-protein nitrogenous compound produced by the breakdown of creatine in muscle and found in serum, plasma, and urine.

C-reactive protein and creatinine are two common diagnostic markers that are used to detect certain medical conditions. Diagnostic markers are biological parameters that help the diagnosis of diseases. They are also called biomarkers.

CONTENTS

1. Overview and Key Difference
2. What is C-reactive Protein  
3. What is Creatinine
4. Similarities – C-reactive Protein and Creatinine
5. C-reactive Protein vs Creatinine in Tabular Form
6. Summary – C-reactive Protein vs Creatinine

What is C-reactive Protein?

C-reactive protein (CRP) is a ring-shaped pentameric protein produced by the liver. It is found in blood plasma. Tillett and Francis discovered this protein in 1930. It was initially thought to be a pathogenic secretion since the elevated level of this protein was observed in a variety of illnesses, including cancer. Later, it was discovered that the liver synthesizes c-reactive protein. The level of c-reactive protein can be diagnosed using methods such as quelling reaction and dynamic light scattering. Normally, the circulating concentration of c-reactive protein rises in response to inflammation. Its concentration increases following interleukin-6 secretion by macrophages and T cells.

The specific physiological role of this protein is to bind to lysophosphatidylcholine expressed on the surface of dead or dying cells. This will activate the complement system via Ciq. Moreover, c-reactive protein was the first pattern recognition receptor (PRR) to be identified. The CRP gene located in chromosome 1 produces c-reactive protein. Structurally, the complete c-reactive protein has five monomers and has approximately a molecular weight of 120,000 Da. Furthermore, the level of c-reactive protein increases during medical conditions such as cardiovascular disease, coronary heart disease risk, fibrosis and inflammation, cancer, obstructive sleep apnea, rheumatoid arthritis, and viral infections.

What is Creatinine?

Creatinine is a non-protein nitrogenous compound produced by the breakdown of creatine in muscle. It is found in serum, plasma, and urine and is released at a constant rate by the body, depending on muscle mass. The serum creatinine is a diagnostic marker of kidney conditions. This is because it is a byproduct of muscle metabolism that is excreted unchanged by the kidneys. When the filtration in the kidney is deficient, the blood creatinine concentration usually rises. Therefore, it can be used as a diagnostic marker for kidney function.

Each day, 1% to 2% of muscle creatine is converted to creatinine. This conversion is non-enzymatic and irreversible. Typically, men tend to have more creatinine than women. Furthermore, the increased dietary intake of creatine or eating a lot of protein may also increase daily creatinine excretion.

What are the Similarities Between C-reactive Protein and Creatinine?

• C-reactive protein and creatinine are two common diagnostics or biomarkers.
• Both are useful to detect certain medical conditions.
• Both are naturally made inside the human body.
• They are present in the blood plasma.

What is the Difference Between C-reactive Protein and Creatinine?

C-reactive protein is a ring-shaped pentameric protein produced by the liver and found in blood plasma, while creatinine is a non-protein nitrogenous compound that is produced by the breakdown of creatine in muscle and is found in serum, plasma, and urine. Thus, this is the key difference between c-reactive protein and creatinine. Furthermore, c-reactive protein can be used to diagnose medical conditions such as cardiovascular disease, coronary heart disease risk, fibrosis and inflammation, cancer, obstructive sleep apnea, rheumatoid arthritis, and viral infections. On the other hand, creatinine can be used to diagnose medical conditions related to the kidney, such as acute or chronic kidney disease.

The below infographic presents the differences between c-reactive protein and creatinine in tabular form for side by side comparison.

Summary – C-reactive Protein vs Creatinine

C-reactive protein and creatinine are two commonly used diagnostic markers for various medical conditions. C-reactive protein is a ring-shaped pentameric protein produced by the liver whereas creatinine is a non-protein nitrogenous compound produced by the breakdown of creatine in muscle. C reactive proteins are found in blood plasma, while creatinine is found in serum, plasma, and urine. So, this summarizes the difference between c-reactive protein and creatinine.

Reference:

1. “Creatinine.” An Overview | ScienceDirect Topics.
2. “C-Reactive Protein (CRP) Test: High vs. Low Levels, Normal Range.” WebMD.

Image Courtesy:

1. “1lj7” By Deposition authors: Ramadan, M.A., Shrive, A.K., Holden, D., Myles, D.A., Volanakis, J.E., DeLucas, L.J., Greenhough, T.J.;visualization author: User:Astrojan – RCSB (CC BY 3.0) via Commons Wikimedia
2. “Creatinine” By Jesse – Own work (CC BY-SA 3.0) via Commons Wikimedia