Diagnosing FCS Without Genetic Confirmation: Scoring Tools and Referral Gaps

Confirming an FCS diagnosis without genetic testing has historically been one of the field's central practical challenges, and the development of the North American FCS score was a direct attempt to address it.

Alan Brown, MD, MHA, describes the debates that shaped the scoring tool. It was built around data available in a standard clinical encounter: lipid panel values, physical findings, clinical history, and a single additional test, the apolipoprotein B level. Because patients with true FCS characteristically have low apo B, a consequence of impaired chylomicron remnant absorption reducing the substrate for VLDL assembly, that value carries particular diagnostic weight. Everything else in the score requires no specialized testing.

Stephan P. Babirak, MD, PhD, frames the tool's practical value by analogy to the Dutch Lipid Clinic Network score for familial hypercholesterolemia: just as the Dutch score supported PCSK9 inhibitor access for patients with a compelling clinical phenotype and a negative genetic test, the North American FCS score provides documentation to support treatment authorization while awaiting or unable to obtain genetic results. Brown adds that the cost and logistics of genetic testing have changed substantially, with several laboratories now supplying collection kits at no charge and out-of-pocket costs having fallen to approximately $250.

The conversation turns to a consequential gap in the referral ecosystem: gastroenterology. Brown notes that triglyceride levels are frequently not measured in the emergency department when a patient presents with pancreatitis. Where a lipid panel is run, a notation of 'lipemic specimen' at the bottom of the laboratory report often goes unaddressed — not from negligence, Babirak clarifies, but because the flag is not prominently displayed and sits outside the gastroenterologist's usual diagnostic frame.

Both experts note that a straightforward protocol, ordering a reflex lipid panel on any lipemic specimen, could capture many patients who currently go undiagnosed. Brown points out that FCS ranks as the third most common cause of pancreatitis overall, behind gallstones and alcohol.

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Our Panelists:

Alan Brown, MD, MHA, is a professor of cardiovascular medicine at Wake Forest University and a past president of the National Lipid Association.

Stephan P. Babirak, MD, PhD, is the founder and medical director of Metabolic Leader, a metabolic and endocrine care center in Scarborough, Maine, where he specializes in lipoprotein disorders.

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Disclosures for Brown include New Amsterdam, Merck, Novartis, Arrowhead, Amgen, Regeneron, and Ionis. Babirak has no relevant disclosures to report.

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References

1. Javed F, et al. Familial chylomicronemia syndrome: an expert clinical review from the National Lipid Association. J Clin Lipidol. 2025;19(3):382-403. doi:10.1016/j.jacl.2025.03.013

2. US Food and Drug Administration. FDA approves drug to reduce triglycerides in adults with familial chylomicronemia syndrome. FDA. November 18, 2025. Accessed June 12, 2026. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-drug-reduce-triglycerides-adults-familial-chylomicronemia-syndrome

3. US Food and Drug Administration. FDA approves drug to reduce triglycerides in adult patients with familial chylomicronemia syndrome. FDA. December 19, 2024. Accessed June 12, 2026. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-drug-reduce-triglycerides-adult-patients-familial-chylomicronemia-syndrome