Fatty acid oxidation defects primary respiratory alkalosis in the absence of toxic ingestion Must be free-flow venous (no tourniquet) or arterial Arterial preferred because skeletal muscle releases ammonia, ice sample immediately, assay promptly Newborns 90–150 μg/dL, children 40–120 μg/dL, adults 18–54 μg/dL (www.pediatriccareonline.org/pco/ub/view/Pediatricdrug-Lookup/153930/0/Normal-Laboratory-Valuesfor-Children ) Normal