Utility of direct measurement of low-density lipoprotein cholesterol in dyslipidemic pediatric patients.
BACKGROUND
Low-density lipoprotein cholesterol (LDL-C) levels are the primary basis for treatment guidelines established for hyperlipidemic children and adolescents. Levels of LDL-C are commonly monitored by means of the Friedewald formula, an indirect calculation that requires an overnight fast. A new method has been developed for the direct measurement of LDL-C (DLDL-C) that does not require fasting. We evaluated the clinical utility of this method.


METHODS
We determined LDL-C concentrations simultaneously by the DLDL-C method, Friedewald equation, and beta-quantification (reference procedure).


METHODS
Pediatric dyslipidemia clinic at Children's Hospital, Boston, Mass.


METHODS
Ninety-two fasting hyperlipidemic pediatric patients.


RESULTS
At the LDL-C concentration cutoffs commonly used for making therapeutic decisions, the DLDL-C method had a significant negative bias (P< or =.05) and misclassified patients into incorrect treatment groups more often than the Friedewald method. The negative predictive value for the DLDL-C method was lower than that for the Friedewald method (P< or =.05), and the cost of determining LDL-C level with the new method was 3 times greater.


CONCLUSIONS
The misclassification potential for LDL-C, and the assay costs, were greater for the DLDL-C method than for the Friedewald calculation. Despite the apparent advantages of the DLDL-C method, we conclude that for hyperlipidemic children the utility of this new method is not advantageous over the conventional Friedewald method. In some conditions, such as in diabetes or marked hypertriglyceridemia, the DLDL-C method may be useful.
Ticho
B S
BS
Department of Cardiology, Children's Hospital, Dana Farber Cancer Institute, Harvard Medical School, Boston, Mass 02115, USA.
Neufeld
E J
EJ
Newburger
J W
JW
Harris
N
N
Baker
A
A
Rifai
N
N
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D003365:Costs and Cost Analysis; D005215:Fasting; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014280:Triglycerides / Q000097:blood
D008078:Cholesterol, LDL; D014280:Triglycerides; D002784:Cholesterol