North American Familial Chylomicronemia Score (NAFCS score)

Calculator

When to use

Current age (years)

< 1

1-9

≥ 10

Body mass index (kg/m²)

≥ 25 or ≥ 85th percentile

< 25 or < 85th percentile

History of pancreatitis

Neither abdominal pain nor pancreatitis

Abdominal pain but no pancreatitis

Pancreatitis

Presence of secondary factors contributing to hypertriglyceridemia

≥ 1

None

All triglycerides > 880 mg/dL

Yes

Ratio triglycerides/total cholesterol > 8 (measured in mg/dL)

Yes

Apolipoprotein B < 1.0 g/L

Yes

Calculation

Please enter all the required inputs.

The North American Familial Chylomicronemia Score (NAFCS) is a clinical diagnostic tool used to distinguish familial chylomicronemia syndrome (FCS) from multifactorial chylomicronemia syndrome (MCS) in patients with severe hypertriglyceridemia. It incorporates routinely available clinical and laboratory variables and was developed based on data and expert consensus from clinical cohorts in the United States and Canada. A score ≥ 60 indicates definite FCS with high specificity, while a score ≥ 45 suggests likely FCS and may guide treatment decisions prior to genetic confirmation. The NAFCS Score outperforms the Moulin Score in North American cohorts and is particularly useful when genetic testing is delayed or inconclusive.

Reference

Robert A Hegele, Zahid Ahmad, Ambika Ashraf et al. Development and validation of clinical criteria to identify familial chylomicronemia syndrome (FCS) in North America. J Clin Lipidol. 2025;19(1):83-94.

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