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Castelli Risk Index II Test

Castelli Risk Index II Test

February 5, 2026
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Do I need a Castelli Risk Index II test?

The Castelli Risk Index II test is most useful if you have a personal or family history of heart disease, high cholesterol, or metabolic conditions like diabetes. It’s also worth considering if you’re experiencing major life changes—such as starting a new medication, adopting a different diet, or beginning an intense exercise program—that could affect your cholesterol profile. If you’re already tracking your heart health closely, or if your doctor has flagged concerns about your cholesterol, this test can add valuable context. For most healthy adults without risk factors or symptoms, routine testing is less likely to offer new insights.This index works by comparing two types of cholesterol: LDL (“bad” cholesterol) and HDL (“good” cholesterol). While standard cholesterol panels give you the numbers, the Castelli Risk Index II reveals the balance between these two, offering a clearer picture of your cardiovascular risk. It’s especially helpful when your total cholesterol or LDL alone doesn’t tell the whole story. Repeat testing is most useful if you’re making significant lifestyle changes or starting new treatments that could shift your cholesterol balance. If your health and habits are stable, repeating the test frequently is unlikely to change your care plan.

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If you’ve been postponing blood testing for years or feel frustrated by doctor appointments and limited lab panels, you are not alone. Standard healthcare is often reactive, focusing on testing only after symptoms appear or leaving patients in the dark.

Superpower flips that approach. We give you full insight into your body with over 100 biomarkers, personalized action plans, long-term tracking, and answers to your questions, so you can stay ahead of any health issues.

With physician-reviewed results, CLIA-certified labs, and the option for at-home blood draws, Superpower is designed for people who want clarity, convenience, and real accountability—all in one place.

Key benefits of Castelli Risk Index II Test

'- Spot your balance of “bad” (LDL) to “good” (HDL) cholesterol for heart health.- Flag early risk for heart attack or stroke, even if total cholesterol looks normal.- Explain why your cholesterol pattern may need more attention than a single number.- Guide your doctor in choosing the best lifestyle or medication plan for you.- Track how well your heart-protective changes are working over time.- Clarify if your cholesterol profile could affect fertility or pregnancy outcomes.- Protect your long-term health by identifying hidden risks before symptoms appear.- Best interpreted with your full lipid panel and personal risk factors.

What is Castelli Risk Index II Test

Castelli Risk Index II is a calculated marker that helps assess the balance between two types of cholesterol in your blood. It is derived from the ratio of low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C). LDL-C, often called “bad” cholesterol, is produced by the liver and carried in the bloodstream to deliver cholesterol to cells. HDL-C, known as “good” cholesterol, is also made in the liver and intestines, but it works in the opposite direction—carrying cholesterol away from the arteries and back to the liver for removal.

The main significance of Castelli Risk Index II is that it reflects the interplay between cholesterol that can build up in artery walls (LDL-C) and cholesterol that helps clear it away (HDL-C). This ratio gives a snapshot of how well your body is managing cholesterol transport and removal. A higher ratio suggests a greater presence of cholesterol that can contribute to artery narrowing, while a lower ratio indicates a more favorable balance. In essence, Castelli Risk Index II helps reveal the underlying dynamics of cholesterol movement in your body, offering insight into cardiovascular risk.

Why is Castelli Risk Index II Test

The Castelli Risk Index II is a powerful marker that reveals how well your body manages cholesterol balance, specifically the relationship between LDL (“bad”) cholesterol and HDL (“good”) cholesterol. This ratio offers a window into your risk for atherosclerosis—the buildup of plaque in arteries—which can affect the heart, brain, and circulation throughout the body. Unlike single cholesterol numbers, this index captures the interplay between harmful and protective cholesterol, making it a more nuanced predictor of cardiovascular health.

When the Castelli Risk Index II is on the lower end of the reference range, it suggests that HDL cholesterol is relatively high compared to LDL. This balance supports healthy blood vessels, reduces inflammation, and helps prevent cholesterol from depositing in artery walls. People with lower ratios tend to have a lower risk of heart attack and stroke, and this protective effect is especially important for women, who often have higher HDL levels before menopause.

Higher values indicate that LDL cholesterol outweighs HDL, tipping the balance toward artery damage and plaque formation. This can silently progress for years, eventually leading to chest pain, heart attacks, or strokes. The risk is particularly pronounced in men and in postmenopausal women, whose HDL levels may drop with age. Children and teens with high ratios may be at risk for early vascular changes, setting the stage for adult heart disease.

Ultimately, the Castelli Risk Index II connects cholesterol metabolism to the health of the entire vascular system. It reflects not just what’s happening in the blood, but how well your body protects itself from long-term damage. Monitoring this index helps reveal hidden risks and guides a deeper understanding of cardiovascular and metabolic health.

What insights will I get from Castelli Risk Index II Test

Castelli Risk Index II compares your LDL cholesterol to your HDL cholesterol. It is a ratio of “cholesterol that tends to deposit in artery walls” (LDL) to “cholesterol involved in reverse transport and cleanup” (HDL). This balance gives a systems-level view of how your body handles lipid traffic, which influences blood vessel integrity, heart and brain blood flow, metabolic flexibility, and, indirectly, organ oxygen delivery and resilience.

Low values usually reflect relatively low LDL and/or robust HDL-mediated clearance of cholesterol. Physiologically, this points to less lipid burden on artery walls, more efficient reverse cholesterol transport, and generally lower atherogenic pressure on the cardiovascular system. In most adults, and across sexes, lower ratios within the accepted physiological range are associated with more favorable vascular health.

Being in range suggests that the push and pull between cholesterol delivery (LDL) and removal (HDL) is reasonably balanced. This supports more stable plaque dynamics, smoother endothelial function, and better maintenance of blood flow to the heart, brain, and peripheral tissues. Many cardiology groups consider values toward the lower end of the conventional “normal” span to be more cardioprotective, especially in people with other risk factors.

High values usually reflect higher LDL relative to HDL, meaning more cholesterol is being delivered to tissues than is being cleared back to the liver. This favors formation and progression of atherosclerotic plaque, endothelial stress, and greater long-term risk of coronary disease, stroke, and peripheral artery disease. The impact is amplified with age, in men earlier than women, and in people with diabetes or metabolic syndrome.

Notes: Interpretation is influenced by the underlying LDL and HDL values, sex hormones, age, genetics, inflammatory status, and use of lipid-altering medications. Fasting versus non-fasting states and acute illness can modestly change the ratio.

Castelli Risk Index II Test and your health

Castelli Risk Index II compares your “bad” LDL cholesterol to your “good” HDL cholesterol, giving a snapshot of how cholesterol balance may affect blood vessels and organs throughout the body.

Heart & Circulation

- High ratio (LDL high, HDL low): Signals higher atherosclerotic risk—cholesterol is more likely to deposit in artery walls, raising chances of coronary artery disease, stroke, and peripheral vascular disease. Often linked to insulin resistance, abdominal obesity, and sometimes hypothyroidism or kidney disease. - Low ratio (LDL low, HDL adequate): Generally favorable and associated with lower cardiovascular risk.

Energy & Muscles

A higher ratio is often seen alongside metabolic issues that impair blood flow and oxygen delivery to muscles, contributing to exertional fatigue, reduced stamina, and leg discomfort with walking (claudication).

Brain & Mood

Unfavorable ratios track with higher risk of carotid and cerebral vessel disease over time, which can impact memory, processing speed, and stroke risk. Chronic vascular risk also interacts with depression and cognitive decline.

Metabolism & Hormones

High Castelli II often accompanies central obesity, prediabetes/diabetes, PCOS, and low-grade inflammation; thyroid and liver disorders can worsen the pattern.

Monitoring Castelli Risk Index II helps detect vascular risk early, guiding lifestyle and medical strategies to protect long-term heart, brain, and metabolic health.

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Frequently Asked Questions

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How it works
What should I expect during a blood draw?
  • A trained phlebotomist will guide you through the process.
  • A tourniquet is placed on your arm, the site is cleaned, and a small needle is used to collect blood into one or more tubes.
  • Results are usually ready in about a week.
  • Most people feel only a quick pinch.
  • The needle is removed, gentle pressure is applied, and a bandage is placed.
How do I prepare for a blood draw?
  • Drink plenty of water beforehand — hydration makes veins easier to find.
  • Wear loose sleeves so your arm is easy to access.
  • Follow any fasting instructions you’ve been given.
  • Let us know if you’re on medications, have fainted before, or have needle anxiety.
What should I do after my blood draw?
  • Press gently on the site for a few minutes.
  • Keep the bandage on for 4-6 hours.
  • Skip heavy lifting or strenuous exercise for the rest of the day.
  • Drink extra water to rehydrate.
  • Monitor the site for redness, swelling, or pain.
How do I book a blood draw with Superpower?

Your membership includes:

  • An annual full body test and report across 100+ biomarkers
  • A personalized action plan to optimize your biomarkers and reach your health goals
  • A dashboard to centralize your health data and track changes across a lifetime
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Many concierge clinics charge $10k – $100k for their services, we’ve built technology to make the world’s best healthcare as accessible as possible via an all-in-one membership.

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Superpower is currently available in the following US states:

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Does Superpower replace my primary care provider?

Superpower specializes in prevention-based testing and treatments and is not intended for emergency or immediate health issues.

While you will have a Superpower care team, your annual membership is designed to complement a primary care doctor if you have one, not replace them.

We are happy to help you share any test results with an outside provider to ensure you receive well-rounded medical care.

How fast are blood test results and how do I read them?

Your annual lab test panel takes about a week to process. We will text you as soon as they become available in your dashboard. Other types of tests may have different testing windows. The Superpower concierge is your own health assistant who helps answer your questions on your results, ensure smooth scheduling, coordination of any office-based tests and navigating you to interface with your care team.

Does Superpower accept health insurance?

Superpower membership and products are all eligible for HSA/FSA funding.

We see Superpower like a gym membership for those committed to prevention and performance. Superpower is a bridge between wellness and healthcare. Health insurance traditionally focuses on reactive care whereas, at Superpower, we believe it’s never too early to start looking out for your long-term health.

What if I want more than 1 blood test per year?

Absolutely — you're not limited to just one. Your membership includes one comprehensive 100+ biomarker blood test each year, but if you'd like to track your progress more closely, you can add extra tests at any time. Each additional full-panel test come at an additional cost. You can order as many as you'd like throughout the year.

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Frequently Asked Questions about Castelli Risk Index II Test

What is Castelli Risk Index IIbiomarker and why is it important in health?

The Castelli Risk Index II is a ratio of LDL cholesterol to HDL cholesterol in the blood, used to assess the risk of cardiovascular disease; higher values indicate a greater risk of heart problems due to unhealthy cholesterol balance.

How does a Castelli Risk Index II test help diagnose specific conditions?

Castelli Risk Index II (LDL/HDL ratio) doesn’t diagnose disease but refines risk assessment for atherosclerotic cardiovascular disease—especially coronary artery disease, heart attack, and stroke—by reflecting atherogenic balance; elevated ratios, alongside other clinical data, flag at‑risk individuals who may need further evaluation and preventive therapy.

What are the symptoms and risks associated with abnormal Castelli Risk Index II levels?

Castelli Risk Index II (LDL/HDL) is usually asymptomatic; a high ratio flags atherosclerosis risk with chest pain, breathlessness, claudication, erectile dysfunction, and events like heart attack, stroke, and PAD. Low ratio is generally protective. Higher risk/atypical presentations: men, postmenopausal women, diabetics, smokers, South Asians, and children with familial hypercholesterolemia.

What causes Castelli Risk Index II levels to become abnormal?

CRI‑II (LDL/HDL) rises with high LDL or low HDL from genetics (FH, PCSK9/ApoB, ABCA1/ApoA‑I), insulin resistance/obesity, hypothyroidism, CKD, smoking, unhealthy diet, pregnancy/menopause, and drugs (steroids, protease inhibitors, older beta‑blockers); it lowers with PCSK9 loss, CETP deficiency, exercise/weight loss, statins/PCSK9 inhibitors, estrogen therapy, bariatric surgery; men/aging worsen ratios.

How should I prepare for a Castelli Risk Index II test and what do the results mean?

Fast 8–12 hours (water/meds ok unless told otherwise), avoid alcohol/high‑fat meals; CRI‑II is LDL/HDL from a lipid panel. Low ratio suggests lower cardiovascular risk; high suggests higher risk; “normal” implies average risk—always interpret with other lipid values, overall risk factors, and clinician guidance.

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