Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1058 page)

Normal In

   Mumps

   Macroamylasemia

   Lower value in neonates

   Limitations

   Certain drugs such as cholinergics and opiates may elevate serum lipase.

   Renal disease may elevate the serum lipase.

LIPOPROTEIN-ASSOCIATED PHOSPHOLIPASE A
₂
(Lp-PLA
₂
)
*

   Definition

   Lipoprotein-associated phospholipase A
₂
(Lp-PLA
₂
) is a 45-kDa protein enzyme produced by inflammatory cells and activated endothelial cells. It travels in the blood mainly with LDLs. Lp-PLA
₂
hydrolyzes oxidized phospholipids in LDLs, resulting in formation of oxidized free fatty acids and lysophosphatidylcholine, which is proatherogenic. Alternate name is plateletactivating factor acetylhydrolase (PAF-AH).

   Use

   Lp-PLA
₂
is considered a risk marker rather than a risk factor for cardiac heart disease.

   In conjunction with hsCRP assay can reliably stratify low-, intermediate-, and high-risk populations.

   Increased Lp-PLA
₂
with low LDL-C increases risk of heart disease two times.

   Increased Lp-PLA
₂
with high CRP increases risk of heart disease three times.