The standard lipid panel

The basic panel gives you five numbers — and two more for free. The trap is that the 'standard' reference ranges and the 'optimal' targets are different things: a result that reads 'normal' can still be well above where a higher-risk person wants to be.

The five numbers

Standard vs. optimal: LDL-C: 'optimal' <100 mg/dL (<2.6 mmol/L) for most, but the risk-based targets go lower — <70 (<1.8) for high risk, <55 (<1.4) for very-high risk. Triglycerides: normal <150 (<1.7); optimal <100 (<1.1), ideal <70. HDL: the 40–60 range is the reassuring zone — both very low and very high (>80) associate with higher mortality (a U-curve), and it's a marker, not a lever. Non-HDL (total minus HDL) captures the cholesterol in all atherogenic particles; target = your LDL goal + 30.
The ratios (free bonuses): Two useful numbers hide in every panel at no extra cost. Total/HDL <3.5 is a strong overall marker. Triglyceride/HDL (in mg/dL) is a cheap insulin-resistance and small-dense-LDL proxy — <2 optimal, >3 flags likely insulin resistance (caveat: less valid in Black patients, who run lower triglycerides). And remnant cholesterol = total − LDL − HDL: ideally <24 mg/dL — a causal, atherogenic fraction that standard LDL misses.
The LDL catch: LDL is usually calculated, not measured (the Friedewald equation), and it underestimates LDL when triglycerides are up — labelling people 'at goal' when they aren't. When triglycerides are elevated, prefer the Martin-Hopkins calculation, a directly-measured LDL, or simply read non-HDL cholesterol (which needs no assumption). Evidence ●●●●○

'Optimal' is not a target for everyone

The aggressive <55 / <70 mg/dL LDL goals are for people with established disease or high calculated risk — not blanket goals for healthy low-risk adults, for whom <100 LDL and <130 non-HDL are perfectly reasonable. Match the target to the risk.

The Cholesterol Guide