Relationship between Treponema EIA and TPPA positivity

• Research type

  Research Study

• Full title

  Relationship between Treponema antibody enzyme immunoassay (EIA) signal strength derived using the Siemens ADVIA Centaur platform and syphilis positivity in other treponema tests from samples tested at Clinical Microbiology and Public Health Laboratory (CMPHL), Addenbrookes between 2015 and 2019

• IRAS ID

  277575

• Contact name

  Olajumoke Sule

• Contact email

  jumoke.sule@addenbrookes.nhs.uk

• Sponsor organisation

  UKHSA

• Duration of Study in the UK

  0 years, 5 months, 4 days

• Research summary

  Syphilis, a sexually transmitted disease, is caused by the organism Treponema pallidum. The diagnosis of syphilis is undertaken by a combination of specific and non- specific treponema tests. Using the ‘reverse testing’ algorithm now widely used in the UK, high throughput automated enzyme immunoassay (EIA) instruments detecting Immunoglobulin G (IgG) against a pool of Treponema pallidum antigens are used for initial testing (screening), with subsequent testing (“confirmation”) by additional treponema and non-treponema tests, Treponema Pallidum Particle Agglutination Test (TPPA) and non-specific Rapid Plasma Reagin test (RPR). It has recently been shown that samples with a high EIA index (assay signal strength) are positive on confirmatory testing and may not require further tests for confirmation. This finding requires confirmation and will require validation using the Siemens ADVIA Centaur platform used in our laboratory and in our group of patients before it can be put to practice.
  This study is being undertaken (i) to describe the quantitative relationship between EIA index and the probability of testing positive in TPPA and RPR tests in our laboratory and (ii) to describe the EIA index cut-off level at which at least 95% of samples reactive by EIA confirm positive in confirmatory test TPPA
  All inpatient and outpatient samples sent to our laboratory from users of our service (NHS and private hospitals and general practitioners) for diagnosis of syphilis between 2015 and 2019 will be included except the following
  i. Quality control samples
  ii. Samples from neonates who may have antibody transferred from mother via the placenta
  iii. Clinical anonymised samples from organ donation or blood transfusion service
  iv. Non-clinical anonymised research samples
  v. Samples from Prisons

  No procedures will be undertaken on patients and the results of this study will not affect patient management.

  The results may apply to other centres using the same EIA platform.

• REC name

  East of England - Cambridge Central Research Ethics Committee

• REC reference

  20/EE/0059

• Date of REC Opinion

  19 Mar 2020

• REC opinion

  Favourable Opinion