The Implementation of an Automated EIA Platform into An Enteric Department

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The Implementation of an Automated EIA Platform
into An Enteric Department

• Shaun Livsey
• BMS2
• Leicester

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Changes in working practice brought about by the
introduction of an automated EIA platform in an
enteric section
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Before the Introduction of an Automated EIA
System...

• Gave all stool samples to Virology to do tissue
  culture CPE and neutralisation for C.difficile
  toxin detection.
• SOP required all stools for full culture to be
  tested for Cryptosporidium using fluorescent
  microscopy. (Stuck in the dark for hours with a
  hundred negative slides)
• Full, labour intensive, formal ether faecal
  concentration and manual microscopy was performed
  on
• Any foreign travel Paris !
• Prolonged gastric upset
• Box tickers (gt30 OCPs to read)
• Large QuantiFERON runs done manually twice a
  week. (Occasional expensive plate failure,
  unknown number of pipetting errors)

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Opportunity- Every cloud....

• About 4 years ago, major problem with C.difficile
  levels in the Trust - needed action - funding
  available.
• Diagnostic speed needed to be increased to help
  reduce the problem tissue CPE too slow EIA.
• Funding for an auto-analyser agreed if 24hr
  turn-around 365 days a year.
• T4 or Triturus (Inverness Medical) trialled
  then bought.
• ToxA/B II EIA test (Techlab) chosen for CDT
  diagnosis.

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Changes...

• Enteric lab took back CD Toxin testing.
• Changed to faster, reliable EIA format.
• Also moved to EIA for combined Cryptosporidium/Gia
  rdia diagnosis.
• POC device used to differentiate positives (RIDA
  Quick Crypto Giardia from r-biopharm).
• Moved QuantiFERON EIA from manual format to
  automated.

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More changes...

• Review of manual OCP data showed that the
  number of significant findings, excluding Giardia
  and E.coli 0.24 of OCPs
• Therefore decision to drop OCP on request or
  vague indicators
• Now only OCP if
• OCP is only request
• Travel outside N. Europe or N. America
• Specific indicators e.g. Eosinophilia.
• Drop from gt30 to 5-10 a day big time saving.
• Giardia diagnosis has more than doubled (Now
  detected for in all cultured samples)
• Doubled Cryptosporidium diagnosis
• Far less tray failure in QuantiFERON runs.
  Confident that right sample in right well

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T4
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Problems...

• Particulates blocking pipettes
• System designed to pipette blood/serum- not lumpy
  faeces. Lumen of conductive tips is very small.
• Initial work caused high levels of blocking.
• Resolution
• Needed to increase volume of stool and diluent.
• Needed to reduce lumen of sample tube.
• Needed to centrifuge mixture just before T4
  sampling.
• Mucoid samples are still problematic
• Block rate around 2-3 per full tray

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More problems...

• Bubbles
• Level detection looks for two identical levels
  before going under
• If large bubble does not burst air pocket
  sampled
• Resolution -
• Gentle handling after centrifuge
• Caution with controls which are not centrifuged

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More problems....

• Limit to T4 Software
• Software not up to QuantiFERON calculations
• Three tube system is too odd to handle
• Resolution
• Cellestis produced a sub-programme
• Not slick, but works

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Current situation

• Full automation others manual pipette
• Changes accepted and routine
• Younger staff happy with this technology
• Older staff some issues!
• SOP written with Band 4 in mind One BMA2 coped
  very well
• Instrument is robust but repairs via Grifols are
  very prompt

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Future

• Dropping CD Toxin A/B testing?
• Using GDH as a primary screen for C.difficile
• Introduction of other enteric toxin detection
• Clostridium perfringens toxin?
• Shigga toxin detection replacing O157 culture?
• Some space for other non-enteric EIAs on machine
  more if extended working hours

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Thanks for listening