Effects of tissue handling and processing steps on PCR for detection of Mycobacterium tuberculosis in formalin-fixed paraffin-embedded samples.

Author(s): Barcelos D, Franco MF, Leão SC

Publication: Rev Inst Med Trop Sao Paulo, 2008, Vol. 50, Page 321-6

PubMed ID: 19082372 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effect of formalin buffering, fixation duration and embedding media on amplification of beta-actin and tuberculosis gene IS6110 in lung and spleen specimens from a single individual.

   Summary of Findings:

   Beta-actin was amplifiable in lung and spleen regardless of fixation duration, formalin buffering and embedding media. The tuberculosis gene IS6110 was detected by agarose gel visualization of PCR products in 60-70% of specimens fixed with buffered formalin but only 50% fixed with unbuffered formalin; however, the use of hybridization probes increased visualization to 90-100% and 70-80%, respectively. The use of pure paraffin instead of paraffin mixed with bee's wax increased detection of IS6110 in lung, but not spleen.

   Biospecimens

   • Tissue - Lung
   • Tissue - Spleen

   Preservative Types

   • Formalin

   Diagnoses:

   • AIDS/HIV-related
   • Autopsy
   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   DNA	PCR

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Time in fixative	4 h 6 h 12 h 24 h 48 h
   Biospecimen Preservation	Embedding medium	Paraffin Bee's wax
   Biospecimen Preservation	Type of fixation/preservation	Formalin (buffered) Formalin (unbuffered)
   PCR Specific	Targeted nucleic acid	Beta-actin Tuberculosis gene IS6110
   Biospecimen Acquisition	Biospecimen location	Lung Spleen

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