A comparison of three fingerstick, whole blood antibody tests for Helicobacter pylori infection: a United States, multicenter trial

We compared three whole blood antibody tests for Helicobacter pylori ( H. pylori ) in a United States, multicenter trial. Methods Patients referred for EGD at three medical centers were recruited. During EGD, biopsies were taken for histology and rapid urease testing (RUT). Immediately after endoscopy, patients underwent the antibody tests (FlexPack HP, Abbott Diagnostics; QuikVue, Quidel Corporation; AccuMeter, ChemTrak) using whole blood obtained by two to three fingersticks. Performance characteristics were calculated for each antibody test using the biopsy-based methods as a gold standard. Results A total of 131 patients participated; 50 (38%) patients had histological evidence of H. pylori infection. Using histology as a gold standard, the sensitivities of FlexPack HP, QuikVue, and Accumeter were 76%, 78%, and 84%, respectively. Specificity was 79% with FlexPack HP and 90% with QuikVue and Accumeter. There were no significant differences in the performance of the three antibody tests though there was a trend toward superior performance for AccuMeter compared to FlexPack HP ( p = 0.019 ). However, RUT proved superior to FlexPack HP using histology as a gold standard ( p = 0.008 ). Using either concordant histology and RUT results or a positive histology or RUT to define active H. pylori infection, there was no statistically significant difference between the antibody tests. Conclusions There were no statistically significant differences in the performance of the three antibody tests. These tests proved only marginally sensitive in detecting patients infected with H. pylori . Clinicians should be aware of the limitations of these tests, particularly when using them as a sole means of testing for H. pylori .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72148/1/j.1572-0241.1999.1135_x.x.pd

In vivo insulin action is familial characteristic in nondiabetic Pima Indians

Non-insulin-dependent diabetes mellitus (NIDDM) is a genetic disorder characterized by two major pathogenic processes: reduced insulin action and a relative or absolute decrease in plasma insulin concentrations. We studied 116 nondiabetic siblings from 45 families to determine if in vivo insulin action showed any aggregation among siblings. Subjects were Pima Indians from the Gila River Indian Community in Arizona who, as a group, have the highest reported incidence and prevalence of NIDDM in the world. In vivo insulin action was determined by the euglycemic-clamp technique at two rates of insulin infusion in each subject with resulting mean plasma insulin concentrations of 119 and 1938 ??U/ml. After adjustment for age, sex, and degree of obesity, there was significant aggregation among siblings of in vivo insulin action at the high insulin infusion rate (P ???.0001). Family membership independently accounted for ~34% of the variance in this measure of insulin action. Glucose uptake at the lower insulin infusion rate also showed familial aggregation (P .01), with family membership independently accounting for ~15% of the variance of this measurement. We conclude that in vivo insulin action is a familial characteristic. The familial component of insulin action occurs in addition to the effects of obesity, age, and sex on insulin action. Therefore it is not sufficient to simply know that an individual is lean or obese to predict his/her in vivo insulin resistance, because it must also be known whether he/she is from an insulin-resistant or insulin-sensitive family. An alteration of insulin action may be an underlying and potentially genetically determined abnormality in Pima Indians that could help explain the familial aggregation of diabetes in this population. Such a genetic mechanism might also operate in populations with Native American admixture (e.g., Mexicans) as well as other populations