The clinical laboratory analysis estimate of procedure of direct fluorimetric detection of level of extracellular DNA.

: The direct fluorimetric analysis of extracellular free DNA looks like a perspective test for diagnostic and monitoring of oncologic diseases. The major analytical parameters of this technique were evaluated and its regional reference intervals and inter-individual and intra-individual variability as well. It was established that the technique limit of detection equals 42.2 ng/ml and response is linear till 1000 ng/ml (R2>0.99). The freezing/unfreezing of plasma exerts no influence on result of analysis up to fourth cycle. The storage of blood samples during 8 hours before centrifugation has no significant effect on measuring level of extracellular free DNA. The storage of plasma samples at -20oC during a month also has no significant effect. The coefficients of analytical intraday and inter-days variations not exceeded 7.2%. The level of extracellular free DNA in plasma of healthy volunteers amounted to 305±39.5 ng/ml and 422.7±86 ng/ml in serum. The indices of individuality made up to 0.47 and 0.29 (plasma and blood serum correspondingly). Therefore, it is demonstrated that direct fluorimetric technique of quantitative detection of extracellular free DNA is characterized by acceptable for clinical studies level of quality of measurements, simplicity of procedure requiring no preliminary extraction. This technique can become perspective protocol for application in routine laboratory practice.