A laboratory form lies twice: when it writes "normal" relative to a reference range from healthy donors, and when it stays silent about the fact that the calculation formula is no longer applicable. This lesson is about reading the form so that the decision changes.
The composition of a lipid profile that the clinician needs.
- Total cholesterol.
- HDL-C.
- Triglycerides.
- LDL-C — calculated or direct.
- Non-HDL-C = total cholesterol − HDL-C. This is what goes into SCORE2. Kazakhstan Ministry of Health protocol No. 196: optimal <2.6 mmol/L at high risk and <2.2 mmol/L at very high risk (Table 13).
- ApoB — according to ESC/EAS 2019 it can be used as an alternative to LDL-C and is preferable with high TG, diabetes, obesity, very low LDL-C. The Kazakhstan Ministry of Health protocol gives a threshold of >1.44 g/L as diagnostically significant for risk assessment.
- Lp(a) — at least once in a lifetime.
The Friedewald formula in the Kazakhstan Ministry of Health protocol No. 196:
LDL-C (mmol/L) = total cholesterol − HDL-C − TG/2.2.
It is not recommended when TG >4.52 mmol/L or when LDL-C <1.81 mmol/L: then a direct method is needed. Fasting: for TG — yes; LDL-C and non-HDL-C are relatively stable, but the protocol refers to the laboratory's standard.
What changes management — specific decision points, not "a bad test".
- The risk category has not yet been determined. Then the lipids are an input into SCORE2 (non-HDL-C) or a category in themselves: LDL-C >4.9 mmol/L or total cholesterol >8 mmol/L = high risk (ESC/EAS 2025, Table 3).
- Suspicion of FH: LDL-C ≥5 mmol/L in an adult triggers DLCN and cascade screening (Kazakhstan Ministry of Health protocol No. 196).
- The target has not been reached. For very high risk the target is <1.4 mmol/L and −50% from baseline. LDL-C of 1.6 mmol/L after myocardial infarction is not "almost normal" but failure to reach the target.
- TG >4.5 mmol/L — the calculated LDL cannot be relied upon; with very high TG the risk of pancreatitis rises (familial chylomicronaemia syndrome: volanesorsen 300 mg/week is considered at TG >8.5 mmol/L (>750 mg/dL) in the setting of this syndrome, ESC/EAS 2025 Recommendation Table 5, IIa B).
- Lp(a) >50 mg/dL (105 nmol/L) is a risk modifier (IIa B, ESC/EAS 2025), a reason to intensify LDL-C lowering, not a reason to wait for "a drug for Lp(a)".
- Secondary causes: if there are simultaneously high TG, high TSH, nephrotic syndrome, cholestasis — first the background, not straight to PCSK9.
Monitoring after starting or intensifying therapy: ESC/EAS 2019 and 2025 — after 4–6 weeks. Not a year later "at the routine check-up".
The boundary of the lesson. "Target level for everyone = 3.0" is an error provoked by the form itself and even by Table 3 of the Kazakhstan Ministry of Health protocol, where <3.0 mmol/L is given as the diagnostic value of LDL-C. That is the threshold for "is there dyslipidaemia relative to a conventional norm", not the treatment target for a very-high-risk patient. The treatment target is taken from the risk category, not from the reference column.
Another boundary. The course does not teach how to choose a specific laboratory and does not discuss discrepancies in direct LDL between reagents.