Evaluation of the Clinical Specificity of the Active Anthrax Detect™ Plus (AAD Plus) Lateral Flow Immunoassay (LFI)
Condition: Anthrax
MeSH terms: Anthrax
Study type: Observational

Summary: 
      The primary objective of the study is to determine the estimated clinical specificity of the
      AAD Plus. A secondary objective is to determine the estimated sensitivity of the AAD Plus as
      10% of the study subject samples will be contrived to be positive.
    

Detailed description: 
      This study is a multi-site trial assessing the clinical specificity of AAD Plus using
      capillary blood, venous blood, and venous serum samples collected from presumptive anthrax
      negative subjects who present with symptoms consistent with cold, flu or other bronchial and
      febrile infections in the US. At least 440 subjects who meet the study eligibility criteria
      will have 3 blood samples from a single time point tested with the AAD Plus device. The
      samples will be: 1) capillary blood collected by finger stick; 2) venous blood collected in a
      sodium citrate anticoagulant tube; and, 3) serum obtained from venous blood collected in a
      serum separator tube. The capillary blood sample will be tested immediately to avoid clotting
      by an unblinded staff member. The venous blood and serum samples will be tested by a blinded
      staff member as soon as possible after preparation. Additional aliquots of the serum sample
      will be prepared and stored frozen at -20 ± 2°C or colder for possible additional reference
      testing [CDC reverse-transcriptase polymerase chain reaction (RT-PCR) assay (K140426)] in the
      event that any of the subject's capillary blood, venous blood, or serum sample is positive.

      At each clinical site, subjects' paired venous whole blood and serum samples will be randomly
      selected such that 10% of all subjects' samples (total of 40) will be spiked with recombinant
      anthrax lethal factor (LF) to prepare a contrived positive sample. Each clinical site will be
      provided a unique randomization list by the Data Management Center that identifies, which
      subjects will be randomized for spiking with LF. The numbers of spiked samples will be
      distributed approximately equally between all sites. An unblinded site staff member will
      prepare the blinded, spiked (from 40 subjects selected for spiking) and unspiked (from 400
      subjects that are not selected for spiking) venous blood and serum specimens to be tested by
      a blinded staff member. Before the venous blood sample and serum specimens (from subjects
      selected for spiking) are spiked; the unblinded staff member will also test all unspiked
      samples on the AAD Plus and record the results. Then the spiked venous blood and serum sample
      will be given to the blinded staff member for testing. Thus, blinded staff will receive whole
      blood and serum samples that could be either unspiked (presumed negative) or spiked (presumed
      positive) to preserve the blind. In the rare event that the AAD Plus test result is positive
      on the unspiked sample tested by the unblinded staff member, then the unblinded staff member
      will give the unspiked sample from this subject to the blinded operator for AAD Plus testing
      and the subject's serum sample will be sent for reference testing as described above. Blinded
      staff will remain blinded throughout the study to the contrived spiking of the whole blood
      and serum samples as to which samples were contrived.
    

Intervention name(s): Active Anthrax Detect™ Plus (AAD Plus)
Intervention type(s): Diagnostic Test
Intervention description(s): A lateral flow immunoassay rapid test (AAD Plus) for early and presumptive diagnosis of inhalational anthrax.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Male and female subjects, 18 to 90 years of age, with symptoms consistent with cold, flu or
        other bronchial and febrile infections.
      
Biospecimen description: 
      8 milliliters of blood
    
Keywords: Anthrax; Lateral flow immunoassay; Diagnostics