Calculadora de Colesterol LDL

Calcule su LDL (colesterol malo) usando la fórmula de Friedewald

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Colesterol Total TC

Normal: < 200 mg/dL

Colesterol HDL (Colesterol Bueno)

Normal: ≥ 40 mg/dL

Triglicéridos

Normal: < 150 mg/dL

Preguntas Frecuentes (FAQ)

¿Por qué el LDL se llama "colesterol malo"?

El LDL se llama "colesterol malo" porque: (1) Contribuye a la aterosclerosis al depositarse en las paredes arteriales; (2) Desencadena inflamación, atrayendo células inmunes para formar placas; (3) Causa estrechamiento vascular a medida que crecen las placas; (4) Puede llevar a la trombosis cuando las placas se rompen, causando ataques cardíacos o accidentes cerebrovasculares; (5) Existe una relación dosis-respuesta - niveles más altos de LDL significan mayor riesgo cardiovascular. En contraste, el HDL puede eliminar el colesterol de las paredes arteriales y por eso se llama "colesterol bueno".

¿Cómo puedo bajar mi colesterol LDL?

Bajar el colesterol LDL requiere un manejo integral: Cambios de estilo de vida: (1) Dieta: Reducir grasas saturadas y trans, aumentar fibra dietética; (2) Ejercicio: Al menos 150 minutos de ejercicio aeróbico de intensidad moderada por semana; (3) Peso: La pérdida de peso puede bajar el LDL; (4) Dejar de fumar: Dejarlo mejora el perfil lipídico. Medicamentos: (1) Estatinas: Fármacos de primera línea, pueden reducir el LDL 25-50%; (2) Ezetimiba: Terapia adjunta para mayor reducción del LDL; (3) Inhibidores de PCSK9: Fármacos potentes para bajar lípidos; (4) Secuestrantes de ácidos biliares: Fármacos antiguos para bajar lípidos. El tratamiento debe ser guiado por un médico basado en el riesgo individual.

¿Cuándo se debe medir el LDL directamente en lugar de usar la fórmula?

La medición directa de LDL debe realizarse en estas situaciones: (1) Triglicéridos > 400 mg/dL (4.52 mmol/L); (2) Hiperlipidemia tipo III (distribetalipoproteinemia familiar); (3) Mal estado de ayuno o estado no ayuno; (4) Cuando se necesita una evaluación precisa del LDL (como monitoreo del tratamiento); (5) Otras condiciones que afectan la precisión de la fórmula. La medición directa de LDL (como método homogéneo o ultracentrifugación) es más precisa pero más costosa, no adecuada para tamizaje rutinario.

¿Los tests de colesterol requieren ayuno?

Tradicionalmente se requerían 8-12 horas de ayuno antes de los tests de lípidos porque comer afecta los niveles de triglicéridos. Sin embargo, las guías más recientes sugieren: (1) El test no ayuno es aceptable para tamizaje rutinario; (2) El cálculo de LDL puede ser menos preciso cuando los triglicéridos están elevados en estado no ayuno; (3) Los triglicéridos aumentan significativamente en estado no ayuno; (4) El colesterol total y HDL son menos afectados por comer. Recomendación: Si se usa la fórmula de Friedewald para calcular LDL, se prefiere el test en ayuno. Si el LDL se mide directamente, el test no ayuno también es aceptable.

¿Qué tan bajo debe bajarse el LDL?

Los valores objetivo de LDL deben determinarse basándose en la estratificación del riesgo cardiovascular: (1) Riesgo muy alto: LDL < 70 mg/dL (1.81 mmol/L), o incluso < 55 mg/dL (1.42 mmol/L); (2) Riesgo alto: LDL < 100 mg/dL (2.59 mmol/L); (3) Riesgo moderado: LDL < 130 mg/dL (3.36 mmol/L); (4) Riesgo bajo: LDL < 160 mg/dL (4.14 mmol/L). ¿"Más bajo es mejor"? Para pacientes de muy alto riesgo, estudios muestran que bajar el LDL a 50 mg/dL o incluso más bajo es seguro y puede reducir aún más el riesgo de eventos cardiovasculares. Sin embargo, los valores objetivo deben ser determinados por médicos basándose en las circunstancias individuales del paciente.

¿Cuáles son las limitaciones de la fórmula de Friedewald?

La fórmula de Friedewald tiene varias limitaciones importantes: (1) Triglicéridos altos: La fórmula es inexacta cuando TG > 400 mg/dL (4.52 mmol/L); (2) Hiperlipidemia tipo III: La fórmula no se aplica a estos pacientes; (3) Estado no ayuno: Idealmente debería medirse después de 12 horas de ayuno; (4) Naturaleza de estimación: Esta es una fórmula empírica, la medición directa es más precisa; (5) Variación individual: La fórmula asume una relación fija, pero la composición real de VLDL varía. Para decisiones clínicas precisas, especialmente cuando los triglicéridos están elevados, se recomienda la medición directa de LDL.

Descargo de Responsabilidad Médica

Esta calculadora proporciona resultados solo para referencia y no puede reemplazar el diagnóstico médico profesional. La evaluación del colesterol LDL debe ser realizada por profesionales de la salud. La calculadora usa la fórmula de Friedewald que tiene limitaciones y puede no ser precisa para todas las personas. Consulte a su médico para una evaluación apropiada del colesterol y decisiones de tratamiento.

LDL cholesterol is the number most cardiovascular risk decisions are built on, yet on most lipid panels it is never measured. It is calculated from the three values the laboratory does measure: total cholesterol, HDL cholesterol and triglycerides. Understanding which equation produced your LDL matters, because the equations disagree most in exactly the situations where the result changes management, namely low LDL and high triglycerides.

La fórmula

Friedewald (mg/dL):   LDL = Total cholesterol - HDL - (Triglycerides / 5)
Friedewald (mmol/L):  LDL = Total cholesterol - HDL - (Triglycerides / 2.2)
Non-HDL cholesterol = Total cholesterol - HDL

Triglycerides / 5 estimates VLDL cholesterol in mg/dL, assuming a fixed ratio of triglyceride to cholesterol in VLDL particles
Non-HDL cholesterol needs no estimation step and stays valid at any triglyceride level

Friedewald WT, Levy RI, Fredrickson DS, Clinical Chemistry, 1972. The fixed divisor was derived from a small sample and assumes a constant VLDL composition, which is the assumption that fails at high triglycerides.

How the calculation works

Total cholesterol is distributed across three main lipoprotein classes: HDL, LDL and VLDL. Laboratories measure total cholesterol and HDL directly, and measure triglycerides, which travel mostly in VLDL. If the ratio of triglyceride to cholesterol inside VLDL particles were constant, dividing triglycerides by five would give VLDL cholesterol, and subtracting HDL and VLDL from the total would leave LDL. That is precisely what the Friedewald equation does.

The weakness is the fixed divisor. VLDL composition is not constant; it varies with triglyceride concentration and between individuals. As triglycerides rise, the ratio drifts and the divisor of five increasingly overestimates VLDL cholesterol, which makes calculated LDL too low. This is why the equation is conventionally treated as invalid above 400 mg/dL of triglycerides, and why it underestimates LDL well before that ceiling.

The Martin-Hopkins method addresses this by replacing the fixed divisor with one selected from a lookup table indexed by the person's own triglyceride and non-HDL values, derived from a very large clinical laboratory dataset. It is more accurate at low LDL and at raised triglycerides, and many laboratories have adopted it. If your report includes an LDL that differs from what the Friedewald equation gives, this is usually why.

How to read your result

The bands below come from long-standing US guidance and are useful for orientation, but current cholesterol guidelines do not treat LDL as a universal target with one cut-off. Treatment decisions depend on overall cardiovascular risk, so the same LDL can be acceptable in one person and an indication for treatment in another.

An LDL of 190 mg/dL or above in an adult is treated as a specific signal, not just a severe number: it raises the possibility of familial hypercholesterolaemia and prompts family screening.
Non-HDL cholesterol, simply total minus HDL, requires no estimation, stays valid when triglycerides are high, and is a stronger predictor of risk in people with diabetes or metabolic syndrome.

LDL cholesterol	Conventional description
Below 100 mg/dL (2.6 mmol/L)	Optimal
100 to 129 mg/dL (2.6 to 3.3 mmol/L)	Near optimal
130 to 159 mg/dL (3.4 to 4.1 mmol/L)	Borderline high
160 to 189 mg/dL (4.1 to 4.9 mmol/L)	High
190 mg/dL (4.9 mmol/L) and above	Very high, prompts assessment for familial hypercholesterolaemia

Fasting, non-fasting and why your number moves

Lipid panels were traditionally drawn fasting because triglycerides rise after a meal, and because the Friedewald equation is sensitive to triglycerides. Current guidance in both Europe and the United States accepts non-fasting samples for most routine assessment, reserving a repeat fasting sample for cases where non-fasting triglycerides come back markedly elevated.

Biological variation also matters when comparing two results. Total cholesterol commonly varies by several percent between measurements in the same stable person, and triglycerides vary considerably more. A change of a few mg/dL between two panels is usually noise rather than signal, and a treatment decision should rest on the trend across repeated measurements rather than on one reading.

Limitaciones

The Friedewald equation is not valid when triglycerides exceed 400 mg/dL (4.5 mmol/L), and it progressively underestimates LDL at triglyceride levels well below that ceiling.
Accuracy is worst where it matters most for treatment: at LDL below 70 mg/dL, the level many high-risk patients are treated towards, Friedewald can understate the true value substantially.
The equation is not valid in type III hyperlipoproteinaemia or when chylomicrons are present, because the assumed VLDL composition no longer holds.
Errors in any of the three measured inputs propagate directly into the calculated LDL, and each of those measurements carries its own analytical variation.
If your laboratory uses the Martin-Hopkins method or a direct LDL assay, its reported LDL will not match the Friedewald result, and the two should not be compared across time as if they were the same measurement.
LDL is one input to cardiovascular risk. Age, blood pressure, smoking, diabetes, family history and lipoprotein(a) all matter, and no single lipid value determines whether treatment is warranted.

Preguntas frecuentes

Is LDL cholesterol measured or calculated?

On most standard lipid panels it is calculated, not measured, from total cholesterol, HDL and triglycerides. Direct LDL assays exist and are used when the calculation is unreliable, such as when triglycerides are very high.

Why is the Friedewald equation invalid above 400 mg/dL of triglycerides?

The equation estimates VLDL cholesterol as triglycerides divided by five, which assumes a constant composition of VLDL particles. That assumption breaks down as triglycerides rise, so above roughly 400 mg/dL the estimate is unreliable and a direct LDL measurement is used instead.

What is non-HDL cholesterol and why does it appear on my report?

Non-HDL cholesterol is total cholesterol minus HDL. It captures the cholesterol carried by all atherogenic particles, needs no estimation step, and remains valid when triglycerides are high, which makes it particularly useful in diabetes and metabolic syndrome.

Do I need to fast before a lipid panel?

Usually not. Current European and American guidance accepts non-fasting lipid panels for routine assessment, with a fasting repeat reserved for cases where non-fasting triglycerides come back markedly elevated. Follow whatever instruction the ordering clinician gives.

My LDL changed between two tests. Is that meaningful?

Often not. Cholesterol varies biologically between measurements even in a stable person, and triglycerides vary considerably more. Small differences between consecutive panels are usually variation rather than a real change; the trend across several results is what carries information.