For initial screening, healthcare professionals should suspect familial hypercholesterolaemia (FH) in adults with a total cholesterol level greater than 7.5 mmol/l or with a personal or family history of premature coronary heart disease (before age 60 in an index individual or first-degree relative) NICE CG71.
Systematic search of primary care records should be conducted for people younger than 30 years with a total cholesterol greater than 7.5 mmol/l, and for those 30 years or older with a total cholesterol greater than 9.0 mmol/l, as these groups are at highest risk of FH NICE CG71.
Before considering a diagnosis of FH, secondary causes of hypercholesterolaemia should be excluded, such as hypothyroidism, liver disease, nephrotic syndrome, and uncontrolled diabetes NICE CG71.
Use clinical criteria such as the Simon Broome or Dutch Lipid Clinic Network (DLCN) criteria to make a clinical diagnosis of FH in primary care settings, performed by a healthcare professional competent in using these criteria NICE CG71.
If the patient meets the criteria for possible or definite FH (e.g., DLCN score >5 or meeting Simon Broome criteria), they should be referred to an FH specialist service for DNA testing NICE CG71.
Initial genetic testing involves DNA analysis for known disease-causing mutations in the LDL receptor gene or other related genes, following specialist referral NICE CG71.