Scheduled for Research Consortium Social: Research Consortium Grant Findings and Top-Rated Posters, Wednesday, April 26, 2006, 4:30 PM - 6:00 PM, Convention Center: Exhibit Hall Poster Area I


The Precision of a Portable Dry-Chemistry Method of Total Cholesterol Measurement [Measurement]

Rodney G. Bowden1, Paul M. Kingery2 and Lindsey Long1, (1)Baylor University, Waco, TX, (2)University of Hawai’i at Manoâ, Honolulu, HI

Significance: Lipid screening, which is largely unregulated, occurs in a number of settings including but not limited to, shopping centers, churches, community centers, and worksites. The seminal factor in the acceptance of cholesterol screening as a means of referral and risk prediction is the question of precision, accuracy, validity, and reliability with instruments used in the field. The purpose of this study was to compare capillary total cholesterol acquired using the Reflotron to a venous sample taken simultaneously to determine if the Reflotron met NCEP guidelines for accuracy. Design: An announcement and a registration form were distributed with employee paychecks announcing a cholesterol screening program. Capillary and venous samples were collected from screening participants (N=285). The Reflotron sample was taken from the venous sample avoiding the "finger stick" method. Results: Participant's total capillary cholesterol averaged 213.27 mg/dL (SD=44.66 mg/dL) when analyzed on the Reflotron while averaging slightly higher (228.86 mg/dL, SD=40.50 mg/dL) for venipuncture. A paired t-test for variance between groups revealed significant differences in total capillary cholesterol and venous total cholesterol values (t=-41.93, p< .0001). A mean centered coefficient of variation was performed revealing a 3.3% error rate, which is greater than 3% allowable by the NCEP III guidelines. The mean percent bias was -7.28% (SD=3.10%), and absolute mean percent bias was 7.46% (SD=2.64%). The percentage of participants misclassified on TC was 16.85%. Concomitantly, Spearman correlation coefficients were high (r2=.94, p=.01). This study compared the same blood sample using the Reflotron and a CDC approved lab while controlling for technician errors evident in previous studies. The mean percent bias was -7.28% demonstrating a negative bias for TC when using Reflotron with an absolute mean bias of 7.46%. The NCEP recommendation suggests the absolute mean bias should be below 8.9%, demonstrating in this study that the Reflotron performed at an acceptable level. Yet, is still should be noted that based on a 200-mg/dL criterion, false negative screening results occurred in 16.85% of participants. The Reflotron failed to meet the coefficient of variation guideline of £ 3% bias. Though the Reflotron met most of the NCEP III guidelines for accuracy, the portable analyzer provided clinically relevant underestimations of total cholesterol values, especially in the lower and upper values and should be used with caution in cholesterol screenings.


Keyword(s): disease prevention, medical/medical care, worksite

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