Category: Clinical chemistry

In human biology, roughly 75% of whole blood's non-protein nitrogen (NPN) is found in erythrocytes, while the rest is distributed among various nitrogen-containing compounds. Non-protein nitrogenous substances are a diverse group of compounds containing nitrogen but are not large protein molecules, primarily functioning as metabolic waste products. Their concentrations in the blood are crucial markers in clinical chemistry for evaluating renal and hepatic function.

Approximately one-third of the blood's total nitrogen content is comprised of non-protein compounds. These compounds are collectively known as the non-protein nitrogen substances in blood, and they serve as vital markers for assessing metabolic and kidney health.