Improved Histo Antigen Test L. Joseph Wheat

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Improved Histo Antigen Test L. Joseph Wheat

• Notes using the normal view

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Histo Antigenemia After SOT

• Liver transplant
• Fever 4 weeks post TP
• Hc Ag serum 30.5
• Hc Ag urine 0.7
• Thymoglobulin X 4
• Your assessment?

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False-Antigenemia After SOT
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Mechanism False-Antigenemia
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Reduction False Antigenemia
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Improved Accuracy
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Histo Galactomannan Quantitation
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Determination of Cutoff
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Histo Antigen Quantitation
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Interpretative Guideline
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Change in Current vs Prior
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Change in ng/ml vs Units
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Reproducibility ng/ml vs. Units
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Antigenemia Clears First
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Interpretation Change in Antigen
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BAL Testing
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Histo Antigen at Others Lab

• Condition/diagnosis No. false-positive
• Cancer/lymphoma 2
• CXR nodules/infitrate 3
• Sarcoid 3
• Unknown 4
• Misc 5
• fever, malaise, CN palsy, mass, hepatitis

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MiraVista vs IMMY Histo Antigen
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Histo Antigen vs. Fungitell BG
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Histo PCR-Rationale

• Low sensitivity histopathology-50
• Difficulty diagnosing meningitis
• Stain 10
• Antigen 50
• Antibody 70
• False-positive histopathology-?
• Silver stain artifact
• Other fungus C. glabrata, B. dermatitidis
• Protozoa Toxoplasma, Leishmania

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Histo Antigen vs PCR
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Histo PCR Accuracy

• Fluid Sensitivity Specificity
• Urine 4/51 (8) 25/25 (100)
• Serum 0/10 (0) 12/12 (100)
• BAL 2/9 (22) 8/10 (80)
• CSF 0/10 (0) 10/10 (100)
• Hc Ag 0.4 ng/ml
• PCR 2 cfu/ml

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Conclusions

• MiraVista Histo Antigen
• 2nd gen more accurate than original
• Antigen endemic galactomannan
• 3rd gen more reproducible/not retest priors
• No comparable method
• Antigenemia clears first
• Antigenemia until negative, then antigenuria
• No test perfect
• Clinical correlation
• Antigen, serology, cytology culture
• Always repeat antigen ( serology)
• Request advice if unclear