A method of establishing an adjusted calibration curve for an assay that quantifies an analyte polynucleotide using a local instrument that amplifies nucleic acids and monitors synthesis of amplification products as amplification is occurring, said method comprising the steps of: (a) obtaining first and second equations respectively defining first and second calibration curves specific for the assay, wherein each of the first and second calibration curves relates normalized indicia of amplification for analyte polynucleotide standards comprising a known quantity of an analyte polynucleotide to indicia of amplification for a fixed amount of an internal calibrator polynucleotide that co-amplified therewith as a function of starting amounts of the analyte polynucleotide in amplification reactions of the assay, wherein said indicia of amplification are features of real-time run curves which indicate a predetermined level of progress in nucleic acid amplification reactions, and wherein each of the calibration curves is different from the other; (b) obtaining an adjustment calibrator comprising an amount of the analyte polynucleotide and said fixed amount of the internal calibrator polynucleotide; (c) co-amplifying, in a nucleic acid amplification reaction carried out with the local instrument, the analyte polynucleotide and the internal calibrator polynucleotide of the adjustment calibrator; (d) determining indicia of amplification for each of the analyte polynucleotide and the internal calibrator polynucleotide of the adjustment calibrator that co-amplified in the nucleic acid amplification reaction; (e) normalizing the determined indicia of amplification for the analyte polynucleotide to the determined indicia of amplification for the internal calibrator polynucleotide of the adjustment calibrator; (f) determining a ratio between the difference between the normalized value determined for the adjustment calibrator and one of the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator and, the difference between the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator; and (g) establishing a calibration plot that maintains said ratio to the first and second calibration curves at all values of analyte polynucleotide standard, thereby establishing the adjusted calibration curve for the assay on the local instrument. (a) obtaining first and second equations respectively defining first and second calibration curves specific for the assay, wherein each of the first and second calibration curves relates normalized indicia of amplification for analyte polynucleotide standards comprising a known quantity of an analyte polynucleotide to indicia of amplification for a fixed amount of an internal calibrator polynucleotide that co-amplified therewith as a function of starting amounts of the analyte polynucleotide in amplification reactions of the assay, wherein said indicia of amplification are features of real-time run curves which indicate a predetermined level of progress in nucleic acid amplification reactions, and wherein each of the calibration curves is different from the other; wherein each of the first and second calibration curves relates normalized indicia of amplification for analyte polynucleotide standards comprising a known quantity of an analyte polynucleotide to indicia of amplification for a fixed amount of an internal calibrator polynucleotide that co-amplified therewith as a function of starting amounts of the analyte polynucleotide in amplification reactions of the assay, wherein said indicia of amplification are features of real-time run curves which indicate a predetermined level of progress in nucleic acid amplification reactions, and wherein each of the calibration curves is different from the other; (b) obtaining an adjustment calibrator comprising an amount of the analyte polynucleotide and said fixed amount of the internal calibrator polynucleotide; (c) co-amplifying, in a nucleic acid amplification reaction carried out with the local instrument, the analyte polynucleotide and the internal calibrator polynucleotide of the adjustment calibrator; (d) determining indicia of amplification for each of the analyte polynucleotide and the internal calibrator polynucleotide of the adjustment calibrator that co-amplified in the nucleic acid amplification reaction; (e) normalizing the determined indicia of amplification for the analyte polynucleotide to the determined indicia of amplification for the internal calibrator polynucleotide of the adjustment calibrator; (f) determining a ratio between the difference between the normalized value determined for the adjustment calibrator and one of the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator and, the difference between the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator; and the difference between the normalized value determined for the adjustment calibrator and one of the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator and, the difference between the first and second calibration curves at the amount of the analyte polynucleotide of the adjustment calibrator; and (g) establishing a calibration plot that maintains said ratio to the first and second calibration curves at all values of analyte polynucleotide standard, thereby establishing the adjusted calibration curve for the assay on the local instrument.