Electrophoretic measurement of lipoprotein(a) cholesterol in plasma with and without ultracentrifugation: comparison with an immunoturbidimetric lipoprotein(a) method.
OBJECTIVE
Elevated plasma lipoprotein(a) [Lp(a)] is a significant risk factor for vascular disease. Standardization of Lp(a) mass measurement is complicated by the heterogeneity of apolipoprotein(a) [apo(a)]. We investigated whether Lp(a) cholesterol measurement, which is not influenced by apo(a) size, is a viable alternative to measuring Lp(a) mass.


METHODS
Plasma Lp(a) cholesterol was measured electrophoretically, with and without ultracentrifugation, and results were compared to each other and to immunoturbidimetrically measured Lp(a) mass in 470 subjects.


RESULTS
Ultracentrifuged and whole plasma Lp(a) cholesterol levels demonstrated high correlation (R = 0.964). All samples with detectable (>/=2.0 mg/dl) Lp(a) cholesterol had Lp(a) mass >30 mg/dl (the clinically relevant cutpoint), while 59 samples with Lp(a) mass >30 mg/dl did not have detectable Lp(a) cholesterol.


CONCLUSIONS
Lp(a) cholesterol can be measured in whole plasma without interference from VLDL lipoproteins. The relative clinical merits of measuring Lp(a) cholesterol vs. Lp(a) mass or both in combination deserves investigation.
Baudhuin
Linnea M
LM
Department of Laboratory Medicine and Pathology, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Hartman
Stacy J
SJ
O'Brien
John F
JF
Meissner
Irene
I
Galen
Robert S
RS
Ward
Jennie N
JN
Hogen
Scott M
SM
Branum
Earl L
EL
McConnell
Joseph P
JP
D015153:Blotting, Western; D002784:Cholesterol / Q000097:blood*; D004587:Electrophoresis, Agar Gel; D005240:Feasibility Studies; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood*; D008910:Minnesota; D009391:Nephelometry and Turbidimetry; D012016:Reference Values; D012044:Regression Analysis; D012307:Risk Factors; D014461:Ultracentrifugation; D014652:Vascular Diseases / Q000097:blood
D017270:Lipoprotein(a); D002784:Cholesterol