[Influence of selected preanalytical factors on viral DNA detection by PCR method].

INTRODUCTION

Obtaining a reliable laboratory test result depends on many factors, among which preanalytical factors play a significant role. The aim ofthis study was to determine the effect of temperature, storage time of samples and number of freezing and thawing cycles on the results of tests carried out by PCR.

METHODS

The study was conducted in a model of cytomegalovirus (DNA) and with four types of clinical material: whole blood, serum, cerebrospinal fluid, urine and archival samples. After contamination with CMV clinical samples were incubated under various conditions for a specified period of time or subjected to cycles of freezing and thawing. The presence of DNA - CMV were determined by nested PCR method.

RESULTS

The results revealed that in the case of applied levels of contamination and in model used in the study: 1) CMV DNA in samples of clinical material (blood, serum, cerebrospinal fluid, urine) for testing by PCR remains stable for at least 5 days at room temperature or refrigerated and at least 7 days when frozen, 2) Repeated freezing and thawing clinical specimens has no influence on the result of the presence of viral DNA, 3) Isolated viral DNA is stable in the temperature of the freezer and can be subjected to at least 20 freeze-thaw cycles without affecting the PCR results.

CONCLUSIONS

Viral DNA in clinical specimens examined in the applied experimental conditions is stable.