Shifted Termination Assay (STA) - Detection of Mutations/SNPs

Shifted Termination Assay (STATM) technology is TrimGen’s proprietary multi-base primer extension method for highly sensitive and specific mutation detection. The STATM reaction recognizes target sequences (wild type or mutant) and selectively extends the detection primer with multiple nucleotides labeled with fluorescent dyes. The mutation signal is then further enriched by enzymatic reaction to increase the detection sensitivity. The extended STATM fragments are separated by capillary sequencer (Applied Biosystems® 3100, 3130, 3500, 3700 Series Genetic Analyzer) followed by data analysis using GeneMapper® Software.

STATM Advantages

  • Result in 3 hours with 3 simple steps
  • Sequencing-like accuracy- the accuracy is selected by PCR specific primers, primer extension specific primers, enzymatic synthesis, fluorescent dye labeling and fragment size
  • PCR-like sensitivity - The mutation signals are enriched 20 times, the method able to detects low level mutations in clinical samples compare to Sanger sequencing method (see fig below).
  • Clear-cut results - Only show wild type and mutation peak, the mutation peak is identified by both the size and the color of an extended detection primer.
  • Universal protocol - Easy to set up new test panels without changing lab setting. 
  • Established platform - runs on the industry standard seqeuncer (Applied Biosystems® 3100, 3130, 3500 and 3700 Series Genetic Analyzer)

Scheme of STATM Reaction

The STATM assay has an excellent sensitivity by enriching the mutation signal.  Below is the data from same sample analyzed by STA and sequencing methods. The sequencing method is miss read the mutation as wild type. In the STA result the mutation signal is enhanced by enrichment reaction and easily identified.   In general the sequencing method is difficult to read the mutations below 15%.  After signal enrichment, STA method able to detect the low level (1-2%) mutation.  


The STATM technology provide result in less than 3 hours with 4 simple steps