Familial Hypercholesterolemia (FH) Calculator
This Familial Hypercholesterolemia (FH) calculator uses the Dutch Lipid Clinic Network (DLCN) criteria to estimate the likelihood that a patient has familial hypercholesterolemia. FH is a genetic disorder that causes very high LDL cholesterol from birth and significantly increases the risk of premature coronary artery disease.
The Dutch Lipid Clinic Network score was first published in 1999 and remains one of the most widely used tools for assessing the probability of FH in patients with elevated cholesterol levels.
For a detailed explanation of FH diagnosis, genetics, and treatment strategies, read our article on Familial Hypercholesterolemia.
Understanding the DLCN Score
Familial hypercholesterolemia (FH) is one of the most common inherited lipid disorders, affecting approximately 1 in 250 individuals worldwide. It is characterised by markedly elevated LDL cholesterol from birth and carries a significantly increased risk of premature coronary artery disease if left untreated.
The Dutch Lipid Clinic Network (DLCN) score is a validated clinical tool used to estimate the probability that a patient's elevated cholesterol is due to familial hypercholesterolemia rather than polygenic or lifestyle-related causes. It was first published in 1999 and has since become the most widely used FH scoring system internationally.
The score incorporates five domains: LDL cholesterol level, personal history of premature coronary artery disease, family history of early cardiovascular disease or hypercholesterolemia, physical findings such as tendon xanthomas or corneal arcus, and genetic testing results if available. For patients currently on lipid-lowering therapy, the calculator includes a built-in statin-adjusted LDL back-calculation to estimate untreated levels.
DLCN Score Interpretation
| DLCN Score | Interpretation | Clinical Implication |
|---|---|---|
| < 3 | Unlikely FH | FH unlikely. Standard risk factor management applies. |
| 3 – 5 | Possible FH | Further evaluation warranted. Consider family screening and repeat lipid testing. |
| 6 – 8 | Probable FH | Consider genetic testing and referral to a lipid specialist. |
| > 8 | Definite FH | Genetic testing and specialist referral strongly recommended. Cascade screening of first-degree relatives indicated. |
Important: The DLCN score provides an estimate of probability — it does not replace clinical judgement. In many cases, genetic testing or specialist lipid clinic referral will be appropriate regardless of the score. For a detailed guide on distinguishing FH from common hyperlipidemia, read our article on differentiating FH from simple hypercholesterolemia.
When Should FH Be Suspected?
Familial hypercholesterolemia should be considered in any patient with:
LDL cholesterol ≥5.0 mmol/L (190 mg/dL) in adults, or ≥4.1 mmol/L (160 mg/dL) in children, particularly if persistent despite lifestyle measures. Premature coronary artery disease — heart attack, coronary stenting, or bypass surgery before age 55 in men or 65 in women. A family history of severe hypercholesterolemia or early cardiovascular events across multiple generations. Physical signs including tendon xanthomas (especially Achilles tendon or hand extensor tendons), xanthelasma, or corneal arcus before age 45.
Early detection allows treatment with high-intensity statins, ezetimibe, and — where indicated — PCSK9 inhibitors or inclisiran. These therapies can dramatically reduce lifetime cardiovascular risk when initiated early. To learn more about FH, including genetics, diagnosis, and treatment, read our comprehensive guide on Familial Hypercholesterolemia.
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Frequently Asked Questions
The DLCN score is a clinical scoring system developed in the Netherlands to estimate the probability of familial hypercholesterolemia. It uses a combination of LDL cholesterol levels, personal and family history, physical signs, and genetic test results to classify FH as unlikely, possible, probable, or definite. It is the most widely used FH scoring tool internationally and is recommended by both European and international lipid guidelines.
No. The calculator provides an estimate of probability, not a definitive diagnosis. A DLCN score of 6 or above suggests probable or definite FH and warrants genetic testing for confirmation. Genetic testing can identify mutations in the LDLR, APOB, or PCSK9 genes that cause FH. Clinical evaluation by a lipid specialist is recommended for all patients with suspected FH.
Screening should be considered in adults with LDL cholesterol ≥5.0 mmol/L (190 mg/dL), children with LDL ≥4.1 mmol/L (160 mg/dL), individuals with premature coronary artery disease, and anyone with a first-degree relative diagnosed with FH. Cascade screening — testing family members of a confirmed FH patient — is the most cost-effective strategy and is recommended by Australian, European, and international guidelines.
Individuals with untreated heterozygous FH have approximately a 50% risk of coronary heart disease by age 50 in men and age 60 in women. Early treatment with high-intensity statins and, where needed, additional lipid-lowering therapies can reduce this risk to near-normal levels. The earlier treatment begins, the greater the cumulative benefit — which is why identifying FH in childhood or early adulthood is so important.
If the LDL cholesterol was measured while the patient was taking lipid-lowering medication, the calculator applies a correction factor to estimate the untreated LDL level. This is important because the DLCN score was designed using untreated cholesterol values. The correction factor depends on the specific medication and dose. For example, Atorvastatin 40 mg typically reduces LDL by approximately 50%, so the measured LDL is multiplied by 2 to estimate the pre-treatment level.
References
1. Nordestgaard BG, Chapman MJ, Humphries SE, et al. Familial hypercholesterolaemia is underdiagnosed and undertreated in the general population. Eur Heart J. 2013;34(45):3478–3490. doi:10.1093/eurheartj/eht273
2. Defesche JC, Gidding SS, Harada-Shiba M, et al. Familial hypercholesterolaemia. Nat Rev Dis Primers. 2017;3:17093. doi:10.1038/nrdp.2017.93
3. Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias. Eur Heart J. 2020;41(1):111–188. doi:10.1093/eurheartj/ehz455
4. World Health Organization. Familial hypercholesterolaemia (FH): Report of a second WHO consultation. Geneva: WHO; 1999. WHO Report
