Frequently Asked Questions
What is a healthy total-to-HDL ratio?
Below 3.5 is considered optimal by most guidelines. The average for U.S. adults is around 4.5. A ratio above 5.0 indicates elevated cardiovascular risk and warrants a conversation with your clinician. However, the ratio is a screening tool - your absolute LDL level and overall 10-year cardiovascular risk score matter more for treatment decisions.
Why is non-HDL cholesterol useful?
Non-HDL captures all atherogenic (artery-hardening) lipoprotein particles in a single number: LDL, VLDL, IDL, and Lp(a). Several studies show it predicts cardiovascular events at least as well as LDL, and it is calculable without a fasting sample or triglyceride measurement. The ACC/AHA guidelines use a non-HDL target of below 130 mg/dL for most patients.
When is the Friedewald LDL estimate unreliable?
The Friedewald equation (LDL = total − HDL − triglycerides/5) becomes inaccurate when triglycerides exceed approximately 400 mg/dL, because the VLDL/triglyceride ratio is no longer fixed. In that case, direct LDL measurement by the lab is needed. The equation also requires a fasting sample - a post-meal (non-fasting) value will inflate the triglyceride reading and under-estimate LDL.
Do I need to fast before a cholesterol test?
For the Friedewald LDL estimate: yes, a 9-12 hour fast gives the most accurate result. Total cholesterol, HDL, and the total-to-HDL ratio are not significantly affected by recent meals and can be measured in the non-fasting state. For triglycerides: a meal can raise values by 20-30% for up to 8 hours, so fasting is recommended if triglycerides are the clinical focus. This calculator is for informational purposes only and does not constitute medical advice.
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General information only. Not medical advice.
Health & Medical Disclaimer: General information only. Not medical advice.
This calculator provides general health information only and is not medical advice. Results do not replace professional medical evaluation or diagnosis. Consult a licensed healthcare provider before making health decisions. Always seek immediate medical attention for emergencies.