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@ARTICLE{Gies:143170,
      author       = {A. Gies$^*$ and L. Gruner$^*$ and P. Schrotz-King$^*$ and
                      H. Brenner$^*$},
      title        = {{E}ffect of {I}mperfect {C}ompliance {W}ith {I}nstructions
                      for {F}ecal {S}ample {C}ollection on {D}iagnostic
                      {P}erformance of 9 {F}ecal {I}mmunochemical {T}ests.},
      journal      = {Clinical gastroenterology and hepatology},
      volume       = {17},
      number       = {9},
      issn         = {1542-3565},
      address      = {New York, NY},
      publisher    = {Elsevier Science},
      reportid     = {DKFZ-2019-00769},
      pages        = {1829-1839.e4},
      year         = {2019},
      abstract     = {Fecal immunochemical tests (FITs) measure hemoglobin in
                      stool to identify individuals at risk for colorectal cancer
                      (CRC). However, there are many different FITs, with
                      different instructions for fecal sample collection. In
                      routine practice, participants do not always exactly follow
                      these instructions. We assessed the effects of violations of
                      fecal sampling instructions on the diagnostic performance of
                      9 quantitative FITs.We obtained stool samples from 76
                      patients with CRC scheduled for surgery at 4 hospitals in
                      Germany and 100 participants without advanced neoplasms who
                      participated in a prospective colonoscopy screening program.
                      We filled fecal sample tubes according to the manufacturers'
                      instructions or with 3 violations that are likely to occur
                      in routine practice. The diagnostic performance was assessed
                      for a total of 6336 FIT samples (176 participants x 9 FITs x
                      4 sampling methods).Sample collection instructions varied
                      widely among FITs but included 3 key components: multiple
                      insertions of sampling rod into stool, visual check of rod
                      for complete filling with stool, and once-only insertion of
                      stool-filled rod into the tube. Violation of the first 2
                      components (inserting the rod into the stool sample only 1
                      time or not visually checking the rod for complete filling)
                      reduced levels of hemoglobin measured. However, the effect
                      on diagnostic performance was generally small. Violation of
                      the third component (insertion of more stool into the tube
                      than recommended) increased levels of hemoglobin measured in
                      samples and identified more patients with CRC (increase of
                      median sensitivity by almost $10\%$ units) at a small loss
                      of specificity (decrease of median specificity by $2\%$
                      units), and produced highest area under the curve for
                      detection of CRC cases for 6 FITs.Violations of fecal
                      sampling instructions can lead to non-negligible variations
                      in fecal hemoglobin measurements. The limited adverse
                      effects on diagnostic performance indicate the robustness of
                      FITs. The potential for increasing diagnostic performance by
                      collecting more stool material should be followed up in
                      further research.},
      cin          = {C070 / C120},
      ddc          = {610},
      cid          = {I:(DE-He78)C070-20160331 / I:(DE-He78)C120-20160331},
      pnm          = {313 - Cancer risk factors and prevention (POF3-313)},
      pid          = {G:(DE-HGF)POF3-313},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:30851476},
      doi          = {10.1016/j.cgh.2019.03.001},
      url          = {https://inrepo02.dkfz.de/record/143170},
}