There are two limitations of PCR assay:false-positive and false-negative results.
The ability of PCR to generate many copies of a sequence from minute quantities of template DNA necessitates that extreme care be taken to avoid the generation of false-positives.
Although false positives can result from sample -to -sample contamination ,a more serious source is the carry-over of DNA from a previous amplification reaction of the same target.To avoid such false -positives ,specific precautions to control contamination must be taken .
To avoid false-negatives ,it is important to control the presence of inhibitory compounds in blood samples,such as haeme compounds,anticoagulants and large amounts of total DNA .
In PCR for Brucella spp.,no standardization regarding sample preparation ,target sequence,PCR and detection methods has been established so far.
My suggestion is that samples with a +ve blood culture but negative PCR ,should be considered as false PCR negative ;samples with a -ve blood culture but +ve PCR ,should be considered as false blood culture negative ,if there are clinical and serological findings to support the presence of brucellosis; samples with a -ve blood culture and negative PCR ,but with clinical and serological findings to support the presence of brucellosis should be considered as false blood culture negative and false PCR negative.
So, best results can be obtained by combining culture
and PCR ...
The ability of PCR to generate many copies of a sequence from minute quantities of template DNA necessitates that extreme care be taken to avoid the generation of false-positives.
Although false positives can result from sample -to -sample contamination ,a more serious source is the carry-over of DNA from a previous amplification reaction of the same target.To avoid such false -positives ,specific precautions to control contamination must be taken .
To avoid false-negatives ,it is important to control the presence of inhibitory compounds in blood samples,such as haeme compounds,anticoagulants and large amounts of total DNA .
In PCR for Brucella spp.,no standardization regarding sample preparation ,target sequence,PCR and detection methods has been established so far.
My suggestion is that samples with a +ve blood culture but negative PCR ,should be considered as false PCR negative ;samples with a -ve blood culture but +ve PCR ,should be considered as false blood culture negative ,if there are clinical and serological findings to support the presence of brucellosis; samples with a -ve blood culture and negative PCR ,but with clinical and serological findings to support the presence of brucellosis should be considered as false blood culture negative and false PCR negative.
So, best results can be obtained by combining culture
and PCR ...
பாய் .
