Blood banks use transcription-mediated amplification (TMA) based nucleic acid testing to screen donated units for HIV-1 and HCV. Which statement correctly describes TMA?
- A It uses thermostable Taq polymerase with thermal cycling to exponential phase
- B It relies on Bst polymerase and magnesium pyrophosphate turbidity for endpoint reading
- C It is an isothermal method using reverse transcriptase and T7 RNA polymerase, producing RNA amplicons detectable by hybridization probes or chemiluminescence ✓
- D It measures released protons as amplicons are synthesized
Correct answer: C. It is an isothermal method using reverse transcriptase and T7 RNA polymerase, producing RNA amplicons detectable by hybridization probes or chemiluminescence
Explanation
TMA is an isothermal amplification in which reverse transcriptase makes a cDNA copy containing a T7 promoter, and T7 RNA polymerase then generates large quantities of RNA amplicon, allowing very fast exponential growth without a thermocycler. Detection uses labeled probes or chemiluminescence. Option B describes loop-mediated amplification, option A describes conventional PCR, and proton release describes ion semiconductor sequencing.
Reference: Koneman's Color Atlas and Textbook of Diagnostic Microbiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.