Controls for Blood Septicemia Nucleic Acid Tests

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Controls for Blood Septicemia Nucleic Acid
Tests
Mark Manak BBI Diagnostics, Inc. A Division of
SeraCare Life Sciences, Inc.
SoGAT XIX Meeting Berne, Switzerland June 15,
2006
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Sepsis Infection of Blood Stream

• Bacterial infection (Bacteremia) Fungal
  Infection (Candidemia)
• Second leading cause of death among patients in
  non-coronary intensive care units (ICU)
• Tenth leading cause of death overall in US
• Usually diagnosed by culture using specialized
  apparatus to detect and identify any viable
  microorganisms.
• Limitations of Blood Culture
• Relatively insensitive and time consuming 24 to
  48 hrs to results
• gt30 of septic patients are false negative by
  blood culture

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Nucleic Acid Tests for Sepsis

• Roche SeptiFastTM Test
• Highly specific able to detect lt100 organisms
  per ml blood
• Detects microorganisms that cause gt90 of all
  blood stream infections
• Real Time PCR on Light Cycler Platform
• 3 parallel reactions gram positive, gram
  negative, and fungus
• Melting curve analysis of end product ensures
  proper sequence
• Rapid, automated results in less than 5 hours

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ACCURUN 500

• Design Specifications
• Manufactured from P. aeruginosa, S. aureus, and
  C. albicans
• Inactivated to reduce viability gt6 logs.
• Diluted in negative human plasma
• Targeted at low concentration (about 300 CFU/ml )
• Intended Use
• Estimate laboratory testing precision
• Detect errors in laboratory testing procedures.
• Controls for the entire workflow

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Linearity of C. albicans in SeptiFast Test
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C. albicans
Quantification -Channel 640
Tm Calling Channel 640
100 cfu/reaction
100 cfu/reaction
IC
NHP
NHP
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P. aeruginosa
Tm Calling Channel 670
Quantification -Channel 670
100 cfu/reaction
NHP
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Excellent Reproducibility Multiple Lots, Test
Sites
S. aureus P. aeriginosa
C. albicans
Test Site A Test Site B
Test Site A Test Site B
Test Site A Test Site B
cp
1 2 3 1 2 3
1 2 3 1 2 3

• 2 3 1 2 3
• Lot Number

Mean 19.0 20.1
16.8 SD 0.8
0.6
0.6 CV 5
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2
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Stability Studies
Accelerated Stability 37o C
Freeze-Thaw Stability
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ACCURUN 500 Summary

• Stable, low reactive independent quality control
  material
• Made from natural bacteria in plasma diluent to
  mimic clinical sample
• Controls for all test steps extraction,
  amplification and detection
• Well suited for the quality control of Nucleic
  Acid assays for microorganisms in human blood.
• Gram positive, Gram negative and fungal controls
  showed amplification peaks only in the respective
  channels for all lots
• Negative controls showed Internal Control peaks
  only
• Excellent Reproducibility between Control Lots,
  Test Runs, and Test Sites
• Use of ACCURUN 500 will allow laboratories to
  detect immediate testing errors and monitor the
  long term performance of such assays.