2. Use of Fecal Occult Blood Testing as a Diagnostic Tool for Clinical Indications: A Systematic Review and Meta-Analysis
Mindy Winghin Lee, Jonathan S Pourmorady, Loren Laine Am J Gastroenterol. 2020 May;115(5):662-670. doi: 10.14309/ajg.0000000000000495.
Introduction: Fecal occult blood tests (FOBTs) are validated only for colorectal cancer (CRC) screening, but are commonly used as a diagnostic test in other clinical settings. We performed a systematic review to assess performance characteristics of FOBT as a diagnostic test for clinical indications. Methods: Bibliographic databases were searched to identify studies in adult patients with a specific gastrointestinal symptom or condition who underwent FOBT and a reference test and provided data on diagnoses. Our primary end point was sensitivity. Risk of bias was assessed with the QUADAS-2 tool. Results: Twenty-two studies met the inclusion criteria: 12 in iron deficiency anemia (IDA) (5 fecal immunochemical (FIT) and 7 guaiac based), 8 in ulcerative colitis (FIT), and 2 in acute diarrhea (guaiac based). Only 2 studies had low risk of bias on all domains of the QUADAS-2. On meta-analysis, FOBT had a sensitivity of 0.58 (95% confidence interval [CI] 0.53-0.63) and a specificity of 0.84 (95% CI 0.75-0.89) in predicting presumptive causes of IDA at endoscopy, with comparable results for guaiac-based tests and FIT. Sensitivity was higher for CRC (0.83) than non-CRC lesions (0.54). FIT had a sensitivity of 0.72 (95% CI 0.57-0.84) and a specificity of 0.80 (95% CI 0.67-0.89) in predicting endoscopic activity in UC. Sensitivities of FOBT for positive stool culture in acute diarrhea were 0.38 and 0.87. Discussion: Sensitivity of FOBT is poor for IDA: 42% of patients with identifiable causes of IDA had false-negative FOBT. Our results did not show acceptable performance characteristics for FOBT to guide decisions regarding endoscopic evaluation and do not support its use in IDA.
3. Perfume dermatitis
W G Larsen J Am Acad Dermatol. 1985 Jan;12(1 Pt 1):1-9. doi: 10.1016/s0190-9622(85)70001-1.
The most common reaction to fragrance materials seen by practicing dermatologists is allergic contact dermatitis. Photodermatitis is occasionally seen, as is contact urticaria, irritation, and depigmentation. Fragrances are the leading cause of allergic contact dermatitis due to cosmetics. The fragrance mixture can cause false-positive reactions; therefore, it is more desirable to test with a separate series of fragrance materials.
