Comparison of digital PCR with real-time PCR calibrated to the International Scale for BCR-ABL monitoring.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e18545-e18545
Author(s):  
Parth Shah ◽  
Furha Iram Cossor ◽  
Shiva Murarka ◽  
Hemangi Dixit
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dynamic Range ◽  
Residual Disease ◽  
Pearson Correlation ◽  
Cost Effective ◽  
Digital Pcr ◽  
Absolute Quantitation ◽  
International Scale ◽  
Accurate Quantification

e18545 Background: Monitoring BCR-ABL1 fusion transcripts is the cornerstone of management in chronic myeloid leukemia (CML). Real Time PCR(RTPCR) has been the tool of choice for its sensitivity and dynamic range. The International Scale was recently introduced to allow for standardization across laboratories. Chip based Digital PCR(dPCR) which allows for absolute quantitation may obliviate the need for such standardization by giving absolute results.It has the potential to increase sensitivity for detection of minimal residual disease. This assumes great significance as we move into the era of treatment free remission. Methods: A total of 31 EDTA-blood samples of CML patients with known values ranging from 0.003-0.5 IS were processed via an accredited RTPCR protocol calibrated to the IS scale and a parallel dPCR workflow without any specific calibration . The analysis of digital PCR samples was performed on the Thermofisher Cloud Platform. Results: Both RTPCR and dPCR yielded extremely concordant results. The Pearson correlation between the two methods was r = 0.6043 (95%CI: 0.318 to 0.789; p = 0.0003). The calculated BCR-ABL/ABL ratios were comparable with a median of 0.098 for RT-PCR calibrated to the IS (range 0.003-0.55; n = 26) and 0.11 for dPCR (range 0.003-0.37; n = 29). The mean difference for the ratios between the two methods used for the detection was around 0.08. Conclusions: We demonstrate here the capability of dPCR to provide a parallel result to an IS scale calibrated protocol without any standardization. This approach required no specific calibrators or standards and resulted in extremely cost effective testing. This freedom from routine calibration provides for a significantly more robust workflow and greatly increased reliability. Limitations do persist in dPCR on account of limited chip densities which are the main parameter for the Poisson statistics. This has limited the dynamic range on dPCR to a maximum of Log 4 for accurate quantification. However as chip densities and emulsion concentrations increase in these technologies, they are poised to introduce a new era in the quest of accurate quantification.

scholarly journals Development and validation of a method for quantification of common wheat, durum wheat, rye and barley by droplet digital PCR

2021 ◽  
Author(s):  
Christian Schulze ◽  
Anne-Catrin Geuthner ◽  
Dietrich Mäde
Keyword(s):  
Durum Wheat ◽  
Real Time ◽  
Bread Wheat ◽  
Common Wheat ◽  
Real Time Pcr ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Food Fraud ◽  
Single Genome ◽  
Cereal Species

AbstractFood fraud is becoming a prominent topic in the food industry. Thus, valid methods for detecting potential adulterations are necessary to identify instances of food fraud in cereal products, a significant component of human diet. In this work, primer–probe systems for real-time PCR and droplet digital PCR (ddPCR) for the detection of these cereal species: bread wheat (together with spelt), durum wheat, rye and barley for real-time PCR and ddPCR were established, optimized and validated. In addition, it was projected to validate a molecular system for differentiation of bread wheat and spelt; however, attempts for molecular differentiation between common wheat and spelt based on the gene GAG56D failed because of the genetic variability of the molecular target. Primer–probe systems were further developed and optimized on the basis of alignments of DNA sequences, as well as already developed PCR systems. The specificity of each system was demonstrated on 10 (spelt), 11 (durum wheat and rye) and 12 (bread wheat) reference samples. Specificity of the barley system was already proved in previous work. The calculated limits of detection (LOD95%) were between 2.43 and 4.07 single genome copies in real-time PCR. Based on the “three droplet rule”, the LOD95% in ddPCR was calculated to be 9.07–13.26 single genome copies. The systems were tested in mixtures of flours (rye and common wheat) and of semolina (durum and common wheat). The methods proved to be robust with regard to the tested conditions in the ddPCR. The developed primer–probe systems for ddPCR proved to be effective in quantitatively detecting the investigated cereal species rye and common wheat in mixtures by taking into account the haploid genome weight and the degree of milling of a flour. This method can correctly detect proportions of 50%, 60% and 90% wholemeal rye flour in a mixture of wholemeal common wheat flour. Quantitative results depend on the DNA content, on ploidy of cereal species and are also influenced by comminution. Hence, the proportion of less processed rye is overestimated in higher processed bread wheat and adulteration of durum wheat by common wheat by 1–5% resulted in underestimation of common wheat.

Detection of transgenic rice line TT51-1 in processed foods using conventional PCR, real-time PCR, and droplet digital PCR

Food Control ◽  
2019 ◽  
Vol 98 ◽  
pp. 380-388 ◽  
Author(s):  
Xiaofu Wang ◽  
Ting Tang ◽  
Qingmei Miao ◽  
Shilong Xie ◽  
Xiaoyun Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Transgenic Rice ◽  
Real Time Pcr ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Processed Foods ◽  
Conventional Pcr ◽  
Rice Line ◽  
Transgenic Rice Line

scholarly journals Use of Ethidium Monoazide and PCR in Combination for Quantification of Viable and Dead Cells in Complex Samples

2005 ◽  
Vol 71 (2) ◽  
pp. 1018-1024 ◽  
Author(s):  
Knut Rudi ◽  
Birgitte Moen ◽  
Signe Marie Drømtorp ◽  
Askild L. Holck
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dynamic Range ◽  
Covalent Binding ◽  
Biological Research ◽  
Complex Samples ◽  
Ethidium Monoazide ◽  
Food Borne ◽  
Pcr Method ◽  
Membrane Cell

ABSTRACT The distinction between viable and dead cells is a major issue in many aspects of biological research. The current technologies for determining viable versus dead cells cannot readily be used for quantitative differentiation of specific cells in mixed populations. This is a serious limitation. We have solved this problem by developing a new concept with the viable/dead stain ethidium monoazide (EMA) in combination with real-time PCR (EMA-PCR). A dynamic range of approximately 4 log10 was obtained for the EMA-PCR viable/dead assay. Viable/dead differentiation is obtained by covalent binding of EMA to DNA in dead cells by photoactivation. EMA penetrates only dead cells with compromised membrane/cell wall systems. DNA covalently bound to EMA cannot be PCR amplified. Thus, only DNA from viable cells can be detected. We evaluated EMA-PCR with the major food-borne bacterium Campylobacter jejuni as an example. Traditional diagnosis of this bacterium is very difficult due to its specific growth requirements and because it may enter a state where it is viable but not cultivable. The conditions analyzed included detection in mixed and natural samples, survival in food, and survival after disinfection or antibiotic treatment. We obtained reliable viable/dead quantifications for all conditions tested. Comparison with standard fluorescence-based viable/dead techniques showed that the EMA-PCR has a broader dynamic range and enables quantification in mixed and complex samples. In conclusion, EMA-PCR offers a novel real-time PCR method for quantitative distinction between viable and dead cells with potentially very wide application.

42P Method optimization for the detection of chimerism by real-time PCR and droplet digital PCR

2021 ◽  
Vol 32 ◽  
pp. S1358
Author(s):  
I.M. Lambrescu ◽  
V.S. Ionescu ◽  
G. Gaina ◽  
A. Popa ◽  
C. Niculite ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Method Optimization

Evaluation of droplet digital PCR for the detection of black canker disease in tomato

Plant Disease ◽  
2021 ◽  
Author(s):  
Li Wang ◽  
Tian Qian ◽  
Pei Zhou ◽  
Wenjun Zhao ◽  
Xianchao Sun
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Detection Threshold ◽  
Digital Pcr ◽  
Taqman Probe ◽  
Tomato Seed ◽  
Canker Disease ◽  
Probe Set

Clavibacter michiganensis subsp. michiganensis (Cmm), the cause of bacterial canker disease, is one of the most destructive pathogens in greenhouse and field tomato. The pathogen is now present in all main production areas of tomato and is quite widely distributed in the EPPO（European and Mediterranean Plant Protection Organization）region. The inspection and quarantine of the plant pathogens relies heavily on accurate detection tools. Primers and probes reported in previous studies do not distinguish the Cmm pathogen from other closely related subspecies of C. michiganensis, especially the non-pathogenic subspecies that were identified from tomato seeds recently. Here, we have developed a droplet digital polymerase chain reaction (ddPCR) method for the identification of this specific bacterium with primers/TaqMan probe set designed based on the pat-1 gene of Cmm. This new primers/probe set has been evaluated by qPCRthe real time PCR（qPCR） and ddPCR. The detection results suggest that the ddPCR method established in this study was highly specific for the target strains. The result showed the positive amplification for all 5 Cmm strains，and no amplification was observed for the other 43 tested bacteria, including the closely related C. michiganensis strains. The detection threshold of ddPCR was 10.8 CFU/mL for both pure Cmm cell suspensions and infected tomato seed, which was 100 times-fold more sensitive than that of the real-time PCR (qPCR ) performed using the same primers and probe. The data obtained suggest that our established ddPCR could detect Cmm even with low bacteria load, which could facilitate both Cmm inspection for pathogen quarantine and the routine pathogen detection for disease control of black canker in tomato.

Reverse transcriptase droplet digital PCR vs reverse transcriptase quantitative real‐time PCR for serum HBV RNA quantification

2020 ◽  
Vol 92 (12) ◽  
pp. 3365-3372 ◽  
Author(s):  
Umaporn Limothai ◽  
Natthaya Chuaypen ◽  
Kittiyod Poovorawan ◽  
Watcharasak Chotiyaputta ◽  
Tawesak Tanwandee ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Real Time ◽  
Real Time Pcr ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Quantitative Real Time Pcr ◽  
Rna Quantification
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