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False Negative Diagnosis (false + negative_diagnosis)
Selected AbstractsImpact of Valvular Calcification on the Diagnostic Accuracy of Transesophageal Echocardiography for the Detection of Congenital Aortic Valve MalformationECHOCARDIOGRAPHY, Issue 7 2007Akash Makkar M.D. Background: Degeneration of congenital bicuspid or unicuspid aortic valves can progress more rapidly than that of tricuspid valves, and an early diagnosis significantly impacts decision making and outcome. We hypothesized that the extent of valvular calcification would negatively influence the diagnostic accuracy of multiplane transesophageal echocardiography (TEE) for the diagnosis of congenital aortic valve disease. Methods: TEE was performed in 57 patients undergoing aortic valve replacement surgery for aortic stenosis (n = 46), pure regurgitation (n = 9), or significant regurgitation with less than severe aortic stenosis (n = 2). The degree of aortic valve calcification and the number of valve cusps were determined at surgery. Results: Surgical inspection confirmed 14 bicuspid and 43 tricuspid aortic valves. Sensitivity and specificity of TEE for the diagnosis of congenital aortic valve malformation was 93% (13/14) and 91% (39/43) (P = 0.0001), respectively. In patients with no or mild aortic valve calcification (n = 13), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 100% (5/5) and 100% (8/8) (P = 0.001), respectively. In patients with moderate or marked aortic valve calcification (n = 44), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 89% (8/9) and 89% (31/35) (P<0.0001), respectively. In this subgroup of 44 patients, there were four false-positive and one false-negative diagnoses due to valvular calcification. Conclusions: Although TEE is highly sensitive and specific for the detection of congenital aortic valve malformations, presence of moderate or marked calcification of the aortic valve may result in false positive and false negative diagnoses. [source] Screening for the BRCA1-ins6kbEx13 mutation: potential for misdiagnosis,,HUMAN MUTATION, Issue 5 2007Susan J Ramus Abstract Misdiagnosis of a germline mutation associated with an inherited disease syndrome can have serious implications for the clinical management of patients. A false negative diagnosis (mutation missed by genetic screening) limits decision making about intervention strategies within families. More serious is the consequence of a false positive diagnosis (genetic test suggesting a mutation is present when it is not). This could lead to an individual, falsely diagnosed as a mutation carrier, undergoing unnecessary clinical intervention, possibly involving risk-reducing surgery. As part of screening 283 ovarian cancer families for BRCA1 mutations, we used two different methods (mutation specific PCR and multiplex ligation-dependant probe amplification) to screen for a known rearrangement mutation L78833.1:g.44369_50449dup (ins6kbEx13). We found false positive and false negative results in several families. We then tested 61 known carriers or non-carriers from an epidemiological study of BRCA1 and BRCA2 mutation carriers (the EMBRACE study). These data highlight the need for caution when interpreting analyses of the ins6kbEx13 mutation and similar mutations, where characterising the exact sequence alteration for a deleterious mutation is not a part of the routine genetic test. © 2007 Wiley-Liss, Inc. [source] Penile pharmacotesting in diagnosing male erectile dysfunction: evidence for lack of accuracy and specificityINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2002Antonio Aversa Penile pharmacotesting (PPT) with alprostadil (PGE1) represents the most common diagnostic approach to male erectile dysfunction (ED). A positive response , i.e. normal erectile rigidity of sustained duration , is presumed to exclude venous or arterial pathology with enough accuracy. To test this assumption we compared PPT vs. flowmetric results obtained by colour-duplex Doppler ultrasound (CDDU) in patients (pts) undergoing diagnostic evaluation for ED under conditions of maximal cavernous relaxation. A total of 195 non-consecutive impotent pts were diagnosed after dynamic CDDU as non-vasculogenic (NOR), or having arteriogenic (AR), veno-occlusive (VO) or mixed (MX) ED. Maximal erection obtained after PPT was scored as: type-1 (full tumescence , no sustained rigidity, angle on the abdominal plane >90°), type-2 (sustained partial erection, valid for intromission, angle=90°) and type-3 (sustained full erection, angle <90°). Comparing PPT with flowmetric results, we found that a type-3 response had 20% false negative diagnosis of NOR (17% of AR- and 3% of VO- and MX-ED, respectively), while a type-2 response had 63% false negative diagnosis (20% of AR, 37% of VO- and 6% MX-ED, respectively). Type-1 response was associated with the presence of VO dysfunction in 99% of cases. These data suggest that a positive response to PPT (type-2 and type-3) assessed by the visual rating of erection is associated with both arterial (up to 20%) and/or VO (up to 43%) ED, as detected by CDDU. We conclude that PPT alone is a misleading diagnostic test to exclude vascular ED and that dynamic CDDU should be offered to pts investigated for male ED. [source] Ultrasonographic evaluation of the thickness of the small intestinal wall in dogs with inflammatory bowel diseaseJOURNAL OF SMALL ANIMAL PRACTICE, Issue 7 2005H. Rudorf Objectives: To establish whether the intestinal wall thickness, as measured ultrasonographically, is significantly increased in dogs with inflammatory bowel disease (IBD). The results would provide the information necessary to decide whether measurement of ultrasonographic wall thickness can predict IBD in dogs. Methods: The intestinal wall thickness of 75 dogs with idiopathic IBD, as measured by ultrasonography, was compared with recently published normal values. IBD was either confirmed histologically (n=54) or suspected (n=21). In all cases there was a positive response to immunosuppressive treatment. Results: A positive association between intestinal wall thickness in dogs and either the histological diagnosis or the response to treatment was not found. Ultrasonographic intestinal wall measurements do not appear to be able to establish a diagnosis of intestinal inflammation and may result in a false negative diagnosis in cases of IBD. Clinical Significance: The same ,grey zone' of between 4 and 6 mm used in humans can be used in the canine duodenum to distinguish the normal range, reserving the term ,abnormal' for an intestinal measurement greater than 6 mm in the duodenum and greater than 4·7 mm in the jejunum. [source] | ||||||||||