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Understand Castelli Risk Index I

Castelli Risk Index I

Heart & circulation markers

What the test generally measures, and what to ask about it.

Longetic keeps every lab and record you’ve had organized and easy to find, so your own Castelli Risk Index I values sit together on one chart and you walk into your next appointment prepared.

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Updated Jul 13, 2026

What is Castelli Risk Index I?

A calculated ratio of total cholesterol to good (HDL) cholesterol, long used as a snapshot of cardiovascular risk.

This is a calculated value from a routine lipid panel, not a separate test: it divides your total cholesterol by your HDL (Total Cholesterol divided by HDL). A higher ratio means more overall cholesterol relative to the protective kind and can be associated with higher cardiovascular risk, a lower ratio can be associated with a more favorable balance. It is a general indicator, not a diagnosis.

This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Terms of Use.

References

Clinical "Cholesterol Levels: What You Need to Know" MedlinePlus (NIH/NLM). medlineplus.gov/cholesterollevelswhatyouneedtoknow.html.

About our sources

Clinical / professional

Medical societies, specialty colleges, and professional associations whose consensus statements reflect clinical practice standards.

Peer-reviewed research

Original research articles and systematic reviews published in indexed journals and verified through PubMed or DOI.

History of updates

Published · Jul 13, 2026
First published, calculated index, formula + sources independently fact-checked.

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