Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
LDL/HDL Ratio: Your Cholesterol Balance as You Get Older
The LDL/HDL ratio is your LDL cholesterol divided by your HDL. A lower ratio is more favourable and becomes more relevant as cardiovascular risk rises with age. Learn what your value can mean.
Reference Ranges
Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.
Check your own valueWhat It Measures
The LDL/HDL ratio sets two cholesterol values against one another: LDL cholesterol in the numerator and HDL cholesterol in the denominator. LDL particles carry cholesterol to the tissues and can accumulate in the artery wall; HDL particles carry cholesterol back to the liver. The ratio expresses that relation as a single dimensionless number. An LDL of 3.0 mmol/l with an HDL of 1.2 mmol/l, for example, gives a ratio of 2.5.
It is emphatically a calculated number and not an extra tube of blood. The laboratory determines the LDL and the HDL, divides one by the other and prints the result. That looks harmless, but it has two consequences that decide how much this number can be trusted.
The first consequence is that the ratio inherits the weakness of the LDL. In most laboratories the LDL is not measured directly but calculated with the Friedewald formula: total cholesterol minus HDL minus triglycerides divided by 2.2. The formula assumes triglycerides sit within normal limits. If they are high, or the blood was drawn non-fasting, the calculated LDL comes out too low and the ratio therefore looks better than it truly is. The cholesterol/HDL ratio does not have this problem, because total cholesterol and HDL are both measured directly and both barely respond to a meal.
The second consequence is that the ratio leaves entire particle classes out of the picture. VLDL particles and the so-called remnants, the leftover particles that remain once VLDL has released its fat, also carry cholesterol into the artery wall. They appear in neither the numerator nor the denominator of this ratio. Anyone with high triglycerides and many remnants sees none of that reflected in the LDL/HDL ratio. Non-HDL cholesterol, simply total cholesterol minus HDL, does count all of those particles.
Finally: this is not the same number as the cholesterol/HDL ratio. That one uses total cholesterol in the numerator and therefore has a completely different scale, with a usual upper limit around 5. The LDL/HDL ratio uses only the LDL and sits around 3. Anyone who confuses the two reads their result wrong every time.
Why It Matters
The honest answer to the question of what this ratio is worth is: less than most people think. It is an older measure that current guidelines do not use. The European ESC/EAS guideline and the Dutch CVRM standard both set their targets on LDL cholesterol, with non-HDL cholesterol and ApoB as secondary goals. Neither sets a target for the LDL/HDL ratio. Anyone basing their treatment or their lifestyle on this number is steering by a measure the guideline itself does not steer by.
The core of the problem is that a ratio hides the absolute numbers. Take two people. The first has an LDL of 3.0 mmol/l and an HDL of 1.0 mmol/l: the ratio is 3.0. The second has an LDL of 4.5 mmol/l and an HDL of 1.5 mmol/l: the ratio is also exactly 3.0. On paper they are identical. In reality the second person carries fifty percent more atherogenic cholesterol. It is that absolute LDL, not the proportion, which accumulates in the artery wall over decades. A reassuring ratio alongside a high LDL is therefore not reassurance but an arithmetic coincidence.
On top of that, the ratio is blind to part of the burden. VLDL and remnant particles do not count towards it, even though they too carry cholesterol into the artery wall. Precisely in the profile with high triglycerides and low insulin sensitivity, where those particles are numerous, the LDL/HDL ratio therefore systematically underplays the situation. That is exactly the group that needs the extra information most.
And there is no universal cut-off at all. What counts as an acceptable LDL depends on your total risk: age, blood pressure, smoking, diabetes, family history and existing cardiovascular disease together decide where the target sits. The same value can be perfectly fine for one person and clearly too high for another. The upper limit printed on your result is a population reference interval, not a goal.
The practical conclusion is short. If your result also carries a non-HDL cholesterol or an ApoB alongside this ratio, let those weigh more heavily than any ratio. Non-HDL needs no formula and does not break at high triglycerides; ApoB counts the number of harmful particles. Both tell you something this ratio cannot.
When to Test
You rarely order this ratio on its own. The number comes along automatically with a lipid panel, as soon as the LDL and the HDL have been determined. So the real question is when a lipid panel makes sense, and under what conditions the blood was drawn.
Fasting or not matters more here than for most lipids. Total cholesterol and HDL barely change after a meal, so for those you may safely test non-fasting. But triglycerides do rise after eating, and because the LDL is calculated from those triglycerides, that feeds straight through into this ratio. With clearly raised triglycerides, certainly above roughly 4.5 mmol/l, the Friedewald formula is no longer valid and the ratio says little. Repeat the panel fasting before anything is read into it.
Also wait a few weeks after a heart attack, major surgery or a significant infection. Cholesterol falls temporarily in that period, and a panel drawn then underestimates your habitual value.
When comparing two results, allow for natural variation: triglycerides fluctuate day to day by some twenty to twenty-five percent, total cholesterol and LDL by some five to ten percent. A small difference is therefore usually noise rather than a trend.
A new or unexpectedly abnormal lipid profile also deserves a search for an underlying cause before lifestyle takes the blame. An underactive thyroid raises LDL and is often missed, so a TSH belongs in the workup. Poorly controlled diabetes, kidney and liver disease, heavy alcohol use, pregnancy and a range of medicines (corticosteroids, oral oestrogen, isotretinoin, some diuretics and beta blockers, anabolic steroids) can equally explain the picture.
The ratio depends strongly on who you are and which stage of life you are in. The table below gives the direction of the effect, not a cut-off per group.
| Group or situation | What happens to LDL and HDL | Effect on the ratio |
|---|---|---|
| Adult men | HDL is on average lower than in women | At the same LDL the ratio comes out systematically higher, so the unisex limit of 3.0 is in practice stricter for men |
| Women before menopause | Oestrogen keeps HDL higher on average | The ratio comes out systematically lower; comparing with a man says little |
| Around and after menopause | LDL rises, HDL may fall slightly | Both halves move the same way, so the ratio climbs faster than the LDL alone |
| Use of anabolic androgenic steroids | HDL falls sharply, LDL rises | The ratio worsens steeply, often earlier and more strongly than either value on its own |
| Regular endurance exercise | HDL rises slightly, LDL often barely changes | The ratio falls without the amount of harmful cholesterol having gone down |
| High triglycerides or a non-fasting sample | The calculated LDL comes out too low | The ratio looks favourable when it should not |
Always have your result assessed by a doctor, together with your individual cholesterol values and your overall risk profile.
Symptoms
Low Levels
What matters more is that a low ratio does not always mean what you hope. The result can look good for the wrong reasons. With high triglycerides or a non-fasting sample the calculated LDL comes out too low, which makes the ratio look better than it is. Alcohol likewise raises HDL and thereby lowers the ratio, without anything about your health improving. And after an infection, surgery or a heart attack cholesterol falls temporarily, which briefly lowers the ratio.
A low ratio with a high LDL sitting behind it is therefore not reassurance. Always look at the individual values and have a doctor assess the whole picture.
High Levels
Behind a high ratio there can be a raised LDL, a low HDL, or both at once. A raised LDL is by no means always about diet: an underactive thyroid raises LDL and is easily overlooked, and poorly controlled diabetes, kidney disease, cholestasis, liver disease, pregnancy and a number of medicines can equally sit behind it. A low HDL is often linked to smoking, to high triglycerides and reduced insulin sensitivity, and to the use of anabolic androgenic steroids.
A raised ratio is therefore not a diagnosis, and certainly not proof of cardiovascular disease. It is a prompt to pull up the individual values, to rule out an underlying cause and to discuss the whole picture with a doctor, who will weigh your full risk profile.
Lifestyle Tips
The first piece of advice is a warning: do not chase the ratio itself. The number is a fraction, and a fraction can be improved in two ways without anything changing in the underlying situation. Anyone focused on pushing HDL upwards improves the ratio without lowering the amount of harmful cholesterol. That is exactly what large trials of HDL-raising agents showed: HDL went up, risk did not come down. So steer on the LDL, and on non-HDL cholesterol or ApoB where your result carries them.
What genuinely lowers LDL is well known and dull: less saturated and trans fat, more fibre from wholegrains, pulses, vegetables and fruit, a healthy weight, regular activity and not smoking. Stopping smoking also raises HDL, which is one of the few ways in which the ratio and your health move in the same direction.
Alcohol emphatically does not belong on that list. It does raise HDL and therefore makes the ratio look better, but it raises triglycerides at the same time and is not a means of improving your cholesterol profile.
With a new abnormal result, first have an underlying cause ruled out, an underactive thyroid in particular. If you follow your values over time, always test under the same conditions and at the same laboratory, and remember that a small difference falls within natural variation.
And finally: never start, stop or change a cholesterol-lowering medicine on your own initiative on the basis of a self-ordered result. That conversation belongs with your doctor.