Serum free fatty acid level verifies fasting state in children

(HealthDay)—Serum free fatty acid (FFA) concentrations can distinguish children's fed and fasting states, according to a study published online May 3 in Pediatrics.

Shavonne M. Collins, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Maryland, and colleagues examined 442 inpatient (fasting) and 323 post-glucose load oral glucose tolerance test samples of glucose, insulin, and FFA from healthy-weight, overweight, and obese children (age 5 to 18 years) without diabetes. In a cross-sectional study, mean FFA and percentage FFA values below the derived nonfasting cut point were compared in inpatient and outpatient settings (each, 442 children).

The researchers found that for identifying fasting, the area under the receiver operating characteristic (ROC) curve was significantly better for FFA than glucose or insulin (0.998 ± 0.001 versus 0.850 ± 0.016 and 0.906 ± 0.011). The sensitivity and specificity for nonfasting were 99.0 and 98.0 percent, respectively, for FFA <287 mEq/mL. Compared with those studied as inpatients, participants studied as outpatients had lower mean FFA (592.8 ± 17.7 versus 754.0 ± 17.7 mEq/mL). Using the ROC curve-derived cut point, 9.7 and 1.6 percent of outpatient and inpatient FFA values, respectively, were consistent with nonfasting.

"Clinicians cannot assume that all pediatric patients are adequately fasted upon arrival for fasting blood work," the authors write. "An FFA concentration <287 mEq/mL may be useful as a cut-point for nonfasting in children."