Class of recommendation	Level of evidence
Blood collection for triglyceride measurements in adults should be performed after a 12-hour fast. Patients should maintain their usual diet but should not consume alcohol (72 hours) or engage in physical exercise (24 hours). In children, fasting duration varies according to the age group. In infants up to 1 year, blood should be collected after a 3-hour fast or immediately before the next feeding. In noninfants from 2 to 5 years, blood should be collected after a 6-hour fast. Children over 5 years old and adolescents should fast for 12 hours	I	C
To confirm a suspected case of FCS after excluding secondary causes of HTG, triglyceride levels should be: 1) > 1,000 mg/dL, in 3 different measurements, for adults after a 12-hour fasting; 2) > 880 mg/dL, in 3 different measurements, for children and adolescents irrespective of fasting time; 3) in children or adults, a triglyceride level < 170 mg/dL excludes the investigation of hyperchylomicronemia	I	C
Triglycerides > 1,000 mg/dL increase the risk of pancreatitis in patients with FCS	IIa	C
Levels of LDL-C in FCS may be underestimated irrespective of measurement method. However, if measured, Martin’s formula or, preferably, direct LDL testing should be performed	I	C
The FCS diagnostic score is a useful tool for suspected FCS and is recommended as a screening tool for genetic testing	I	C
This document does not recommend measuring LPL activity with heparin, as it may have limited discriminative capacity in carriers of common variants	III	C
Genetic sequencing of the LPL , APOC2 , APOA5 , GPIHBP1 , and LMF1 genes provides a definitive diagnosis of FCS in case of homozygosis or double/compound heterozygosis for pathogenic or probably pathogenic variants	I	C
For confirmed cases of FCS, genetic counseling should be conducted to calculate the risk of condition occurrence or recurrence, both for decision-making and for choosing the contraceptive method, especially in consanguineous unions	I	C
Nutritional therapy should include the following general recommendations: Restriction of fat consumption (10% to 15% of TEI) Exclusion of added sugars (sucrose and corn syrup) Exclusion of concentrated fruit juices Exclusion of alcoholic beverages Consumption of complex carbohydrates in adequate amounts Ensuring the adequacy of essential fatty acids Monitoring consumption of fat-soluble vitamins, with supplementation when necessary Inclusion of MCT for the purpose of calorie intake, according to tolerance	I	C
Intravenous heparin infusion for HP is not recommended in patients with FCS	III	C
The use of low-molecular-weight heparin is indicated as prophylaxis for deep venous thrombosis in HP in patients with FCS	IIa	C
In patients with FCS and HP, intravenous insulin should only be used in those with decompensated type 1 and 2 diabetes, for glycemic control	IIa	C
Plasmapheresis should be indicated for patients with FCS and HP on an individual basis. Potential candidates include patients with severe HP or who persist with triglycerides > 1,000 mg/dL after the first 24 to 48 hours	IIb	C
The indication of plasmapheresis during pregnancy, although safe and effective, should be individualized due to the scarcity of evidence to date	IIb	C
The use of antisense treatment against ApoC3 is recommended for adults aged > 18 years with genetic confirmation of FCS who did not respond to usual treatment and have high risk of pancreatitis	I	C
Platelet monitoring during antisense treatment against ApoC3 should be done initially every 2 weeks and subsequently adjusted according to platelet count	I	B
Antisense treatment against ApoC3 should be spaced if platelets < 100,000/uL, and the drug should be discontinued if platelet count < 75,000/uL	I	B