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Diagnostic accuracy of the APPY1 Test in patients aged 2–20 years with suspected acute appendicitis presenting to emergency departments
  1. Juan González del Castillo1,2,
  2. Francisco Javier Ayuso1,
  3. Victoria Trenchs3,
  4. Mikel Martinez Ortiz de Zarate4,
  5. Carmen Navarro5,
  6. Kinda Altali6,
  7. Cristina Fernandez7,
  8. David Huckins8,
  9. Francisco Javier Martín-Sánchez1,2,
  10. representing INFURG-SEMES group
    1. 1Emergency Department, Hospital Universitario Clínico San Carlos, Madrid, Spain
    2. 2Health Research Institute, Hospital Universitario Clínico San Carlos, Madrid, Spain
    3. 3Emergency Department, Hospital Universitario Sant Joan de Deu, Barcelona, Spain
    4. 4Emergency Department, Hospital Universitario de Basurto, Bilbao, Spain
    5. 5Emergency Department, Hospital Universitario Virgen de la Macarena, Sevilla, Spain
    6. 6Pediatric Department, Hospital Universitario Clínico San Carlos, Madrid, Spain
    7. 7Research Unit, Preventive Medicine Department, Hospital Universitario Clínico San Carlos, Madrid, Spain
    8. 8Division of Emergency Medicine, Newton-Wellesley Hospital, Newton, Massachusetts, USA
    1. Correspondence to Dr Juan González del Castillo, Emergency Department, Hospital Universitario Clínico San Carlos, Calle Professor Martín-Lagos s/n, Madrid 28040, Spain; jgonzalezcast{at}gmail.com

    Abstract

    Objective Evaluate the diagnostic accuracy of the APPY1 Test alone and in combination with the Alvarado score (AS) to rule out acute appendicitis (AA) in patients presenting to EDs with abdominal pain suspicious for AA.

    Methodology Observational study in a prospective consecutive cohort including all patients from 2 to 20 years with abdominal pain suggestive of AA in four EDs. The APPY1 Test was performed and AS was calculated to determine risk stratification for each patient.

    Results 321 patients enrolled (mean age 11.8 (SD 3.8) years, 52.0% male), with 32.4% low risk, 23.7% intermediate risk and 43.9% high risk according to the AS. 111 (34.6%) had AA, of whom 1 (0.9%) had a false-negative APPY1 Test result. The APPY1 Test had a sensitivity (Se) of 99.1% (95% CI 94.4% to 99.9%), specificity (Sp) of 32.9% (95% CI 26.6% to 39.7%), negative predictive value (NPV) of 98.6% (95% CI 91.2% to 99.9%) and negative likelihood ratio (LHR−) of 0.03 (0.00 to 0.19) in this population. For patients at low risk by AS, the APPY1 Test had a Se of 100% (95% CI 62.9% to 100%), NPV of 100% (95% CI 91.1% to 100%) and LHR− of 0.0 (not calculable), and for patients at intermediate risk by AS, the APPY1 Test had a Se of 94.4% (95% CI 70.6% to 99.7%), NPV of 94.7% (95% CI 71.9% to 99.7%) and LHR− of 0.18 (0.0 to 1.2), respectively.

    Conclusions APPY1 Test is a potentially useful diagnostic tool to rule out AA in this population, with clinical utility primarily in those patients classified as having low clinical risk of appendicitis according to the AS.

    • abdomen
    • diagnosis
    • paediatrics

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    Footnotes

    • Collaborators Other members of the Infectious Disease Group of Spanish Emergency Medicine Society are as follows: Lorena Algarrada Vico (Emergency Department, Hospital Sant Joan de Déu Barcelona), Arantxa Aparicio Coll (Emergency Department, Hospital Sant Joan de Déu Barcelona), Marta Batllori Tragant (Emergency Laboratory, Hospital Sant Joan de Déu Barcelona), Alejandro Torres Sampedro (Hospital Universitario de Basurto), Joseba Rementeria Radigales (Hospital Universitario de Basurto), Tarik Chaoui El Kaid (Laboratory Department, Hospital Universitario de Basurto), Jose Gallardo Bautista (Emergency Department, Hospital Universitario Virgen de la Macarena), Mª José Carpio Linde (Emergency Department, Hospital Universitario Virgen de la Macarena), Catalina Sánchez Mora (Laboratory Department, Hospital Universitario Virgen de la Macarena), Jorge García Lamberechts (Emergency Department, Hospital Universitario Clínico San Carlos), Diego Lopez de Lara, Andres Bodas-Pinedo, José Tomas Ramos-Amador (Pediatric Department, Hospital Universitario Clínico San Carlos), María Dolores Ortega (Laboratory Department, Hospital Clínico Universitario San Carlos), Pablo Martinez Camblor (Epidemiology and Preventive Department, Hospital Universitario Central de Asturias).

    • Contributors All authors contributed to the development of the study protocol. JGdC and FJM-S planned the study concept and design. JGdC obtained ethics committee approval and performed the study supervision. FJA, VT, MMOdZ, CN, KA and the members of the Infectious Disease Group of Spanish Emergency Medicine Society collected all data. FJM-S, CF and JGdC analysed and interpreted the data. FJM-S and JGdC prepared the first manuscript draft. All authors contributed to manuscript revision and all approved of the final manuscript. DH made a critical revision of the manuscript.

    • Funding This study had financial support from Infectious Disease Group of Spanish Emergency Medicine Society (INFURG-SEMES). This group has received financial support from Merck, Tedec Meijii, Pfizer, TermoFisher, Laboratorios Rubio and Novartis in the last year to organise conferences and group meetings. The Infection Diseases Group has no direct relationship with Venaxis Inc., the manufacturer of the APPY1 Test, yet has received support from Laboratorios Rubio, the company distributing the APPY1 Test in Spain. Laboratorios Rubio has participated as a sponsor of SEMES meetings in the past two years and offered the APPY1 Test free of charge for the development of this study. The promoter of this study has been INFURG-SEMES. None of the authors has received direct financial compensation from Venaxis Inc. or Laboratorios Rubio, except DH who has participated as an external reviewer of the study and to whom Venaxis Inc. has paid consulting fees and reimbursed for travel expenses to FDA meetings and conferences.

    • Competing interests None of the authors has received direct financial compensation from Venaxis Inc., the manufacturer of the APPY1 Test, or Laboratorios Rubio, the company distributing the APPY1 Test in Spain. DH, who has participated as an external reviewer of the study, has received consulting fees and reimbursed for travel expenses to FDA meetings and conferences by Venaxis Inc. Neither Venaxis Inc. nor Laboratorios Rubio has participated in the development of this study, including funding or writing.

    • Patient consent Obtained.

    • Ethics approval Ethical Committee of Hospital Clínico San Carlos, Madrid, Spain.

    • Provenance and peer review Not commissioned; externally peer reviewed.

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