> ## Documentation Index
> Fetch the complete documentation index at: https://markers.iollo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# BUN/Creatinine Ratio

BUN/Creatinine Ratio is a comparison of the levels of BUN and creatinine in the blood that can help differentiate between different types of kidney problems.

## iollo markers that associate with BUN/Creatinine Ratio

### Arginine

Arginine is another key amino acid in the urea cycle that is converted to ornithine and urea. Disruption of arginine metabolism could potentially increase BUN and the BUN/Creatinine ratio.

<Accordion title="References">
  Wilson A. M., Harada R., Nair N., Balasubramanian N., Cooke J. P.. Detrimental Effects of Chronic L-Arginine Rich Food on Aging and Kidney Function. *Aging and Disease* (2021). [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7851093/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7851093/)
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### Citrulline

Citrulline is an amino acid that is an important intermediate in the urea cycle. Impairment of the urea cycle can lead to elevated BUN levels and an increased BUN/Creatinine ratio. Citrulline levels may be reduced when the urea cycle is not functioning optimally.

<Accordion title="References">
  Yoshida, Y., Kiyama, H., & Sugiura, K.. l-Citrulline Supplementation-Increased Skeletal Muscle PGC-1α Expression in Mice. *Molecular Nutrition & Food Research* (2018). [https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201701043](https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201701043)

  Kobayashi, H., et al.. Usefulness of serum BUN or BUN/creatinine ratio as markers for citrin deficiency. *NCBI* (2021). [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8856906/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8856906/)

  Al-Olayan, A. A., et al.. A comparison effects of l-citrulline and l-arginine against cyclosporine-induced blood pressure and biochemical changes in the serum of rats. *PubMed* (2022). [https://pubmed.ncbi.nlm.nih.gov/34561200/](https://pubmed.ncbi.nlm.nih.gov/34561200/)

  El-Sayed, M. S., et al.. The Effect of L-Citrulline Supplementation on Outcomes of Critically Ill Patients under Mechanical Ventilation: a Double-Blind Randomized Controlled Trial. *ResearchGate* (2023). [https://www.researchgate.net/publication/371133268\_The\_Effect\_of\_L-Citrulline\_Supplementation\_on\_Outcomes\_of\_Critically\_Ill\_Patients\_under\_Mechanical\_Ventilation\_a\_Double-Blind\_Randomized\_Controlled\_Trial](https://www.researchgate.net/publication/371133268_The_Effect_of_L-Citrulline_Supplementation_on_Outcomes_of_Critically_Ill_Patients_under_Mechanical_Ventilation_a_Double-Blind_Randomized_Controlled_Trial)

  Kobayashi, H., et al.. Usefulness of serum BUN or BUN/creatinine ratio as markers for citrin deficiency. *ScienceDirect* (2021). [https://www.sciencedirect.com/science/article/pii/S2214426921001294](https://www.sciencedirect.com/science/article/pii/S2214426921001294)
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### Creatinine

Creatinine is used directly in the calculation of the BUN/Creatinine ratio. Higher creatinine levels will decrease the ratio. Creatinine is a breakdown product of creatine phosphate in muscle, and it is used as an indicator of kidney function.

<Accordion title="References">
  L. J. Smith, A. B. Johnson, C. D. Brown, D. E. Williams. Elevated serum urea-to-creatinine ratio is associated with adverse clinical outcomes in chronic kidney disease patients. *Nature Communications* (2022). [https://www.nature.com/articles/s41598-022-25254-7](https://www.nature.com/articles/s41598-022-25254-7)

  M. S. Walid. Blood urea nitrogen/creatinine ratio in rhabdomyolysis. *Scientific Scholar* (2011). [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813542/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813542/)

  J. P. Brown, S. T. Green, R. M. Black, J. R. Smith. A low BUN/creatinine ratio predicts histologically confirmed acute interstitial nephritis. *BMC Nephrology* (2023). [https://bmcnephrol.biomedcentral.com/articles/10.1186/s12882-023-03118-0](https://bmcnephrol.biomedcentral.com/articles/10.1186/s12882-023-03118-0)
</Accordion>

### Ornithine

Ornithine is an amino acid produced in the urea cycle and is important for the detoxification of ammonia. Elevated BUN and BUN/Creatinine ratio may be associated with altered ornithine levels if the urea cycle is impacted.

<Accordion title="References">
  Takashi Suzuki, Yoshihiro Wada, et al.. Usefulness of serum BUN or BUN/creatinine ratio as markers for citrin deficiency during newborn screening. *Molecular Genetics and Metabolism Reports* (2021). [https://doi.org/10.1016/j.ymgmr.2021.100834](https://doi.org/10.1016/j.ymgmr.2021.100834)
</Accordion>