Obesity

Fasting laboratory tests

• Lipid profile
• Fasting plasma glucosePatient over 45 with a BMI > 28 kg/m².
• GGT (Fatty Liver Index, if BMI ≥ 30 kg/m²)if neededBMI ≥ 30 kg/m²: screening for steatosis by the Fatty Liver Index (BMI, waist circumference, GGT, triglycerides) or by abdominal ultrasound; if normal, recheck at 3 to 5 years ^[2].
• Serum creatinine with GFR (if BMI ≥ 30 kg/m²)if neededBMI ≥ 30 kg/m²: screening for chronic kidney disease (GFR by CKD-EPI and albuminuria) ^[2], to be repeated every year according to the HAS guide on chronic kidney disease, which lists obesity among the risk factors ^[3].
• Urine albumin:creatinine ratio (if BMI ≥ 30 kg/m²)if neededBMI ≥ 30 kg/m²: screening for chronic kidney disease (GFR by CKD-EPI and albuminuria) ^[2], to be repeated every year according to the HAS guide on chronic kidney disease, which lists obesity among the risk factors ^[3].
• ASTif neededSteatosis on ultrasound: FIB-4 fibrosis score, calculated from age, AST, ALT and platelets ^[4]; fibrosis excluded if FIB-4 < 1.30, otherwise quantify the fibrosis ^[2].
• ALTif neededSteatosis on ultrasound: FIB-4 fibrosis score, calculated from age, AST, ALT and platelets ^[4]; fibrosis excluded if FIB-4 < 1.30, otherwise quantify the fibrosis ^[2].
• Platelets (if steatosis)if neededSteatosis on ultrasound: FIB-4 fibrosis score, calculated from age, AST, ALT and platelets ^[4]; fibrosis excluded if FIB-4 < 1.30, otherwise quantify the fibrosis ^[2].

• Overweight with no clinical sign of complication and no indication for diabetes screening: no laboratory tests.

Fasting laboratory tests, depending on the context

• Fasting plasma glucose (screening for type 2 diabetes)if neededFrom 10 years of age or the onset of puberty, if overweight or obese, with at least one risk factor: maternal or gestational diabetes, type 2 diabetes in a 1st- or 2nd-degree relative, signs or conditions of insulin resistance (acanthosis nigricans, hypertension, dyslipidaemia, PCOS, low birth weight for gestational age) ^[12]. Repeat at least every 3 years if normal ^[12].
• Lipid profileif neededEstablished obesity (BMI ≥ IOTF 30 threshold) with a family history of dyslipidaemia ^[12].
• ASTif neededEstablished obesity (BMI ≥ IOTF 30 threshold), depending on family history, the trajectory of the BMI curve and the clinical history ^[12]. Check every 2 to 3 years if normal, especially in adolescence ^[12].
• ALTif neededEstablished obesity (BMI ≥ IOTF 30 threshold), depending on family history, the trajectory of the BMI curve and the clinical history ^[12]. Check every 2 to 3 years if normal, especially in adolescence ^[12].