Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (922 page)

   Zellweger syndrome

   Neonatal adrenoleukodystrophy

   β-Lipoproteinemia

Decreased In

   CF

   Malabsorption (acrodermatitis enteropathica)

   Zinc deficiency (arachidonic acid and linoleic acid low)

   Limitations

   Free fatty acids increase by 12–25% in 24 hours in refrigerated plasma.

   Strenuous exercise, anxiety, hypothermia, and long-term fasting elevate the levels.

   Long-term IV or parenteral nutrition therapy decrease the levels.

   Prolonged fasting or starvation affects levels (rise as much as three times normal).

FECAL FAT

   Definition

   Test for steatorrhea or excess fat in bowel movements due to fat. Helps to estimate the percentage of dietary fat that the body does not absorb

   
Normal range:
<7 g of fat per 24 hours