Rationale:

• Laboratory testing can confirm clinical impressions and provide information not detectable on physical examination.

Evidence:

• Casual glucose >200 mg/dL with symptoms of diabetes constitute a criterion for diagnosis (328).
• Fasting glucose >126 mg/dL on two occasions or 2-hour glucose >200 mg/dL on two occasions during an oral GTT with 75 g of glucose is diagnostic of diabetes (328).
• Impaired fasting glucose is defined as a fasting glucose between 100 and 126 mg/dL (328).
• Impaired glucose tolerance is defined by a glucose between 140 and <200 mg/dL at 2 hours during an oral GTT (328).
• Low HDL cholesterol and high triglycerides are components of the metabolic syndrome (236).
• Ultrasound of the liver has a good correlation with hepatic fat (329).
• Metabolic syndrome can be diagnosed by several criteria. The metabolic syndrome and its individual components predicted the incidence of cardiovascular disease and stroke equally well (330).

Comments:

• If a child's weight is above the 99^th percentile for height and rising further above this upper bound, genotyping for genetic disorders associated with obesity may be considered. For example, children with very high BMI may have genetic defects in melanocortin receptor or other genes (62).