Venesection needle coring increases positive results with RT-PCR for detection of circulating cells expressing CEA mRNA.
We assessed whether circulating cell positivity using RT-PCR for carcinoembryonic antigen (CEA) cDNA was affected by venesection via a needle compared with a pre-aspirated venous cannula, and by increased PCR cycles. Systemic blood was sampled by needle and pre-aspirated cannula in 101 healthy individuals with no cancer history. After erythrocyte removal, samples were subjected to RT-PCR using specific primers for CEA, with 29 or 35 RT-PCR cycles. There was a significant difference between the number of subjects whose samples were negative when collected via needle venesection and positive when collected via pre-aspirated cannula, compared with positive by needle venesection and negative by pre-aspirated cannula for both 29 (P = 0.016) and 35 (P = 0.0111) RT-PCR cycles. Venesection technique (P = 0.01) and number of cycles (P = 0.003) were significant predictors of a positive result. Positive results in healthy subjects were reduced to less than 3% when an aspirated cannula was used for venesection and >29 PCR cycles were avoided.
Wharton
R Q
RQ
Department of Surgery, Imperial College School of Medicine, London, UK.
Patel
H
H
Jonas
S K
SK
Glover
C
C
Weston
M
M
Allen-Mersh
T G
TG
D000328:Adult; D002272:Carcinoembryonic Antigen / Q000097:blood*; D002404:Catheterization / Q000295:instrumentation; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D009339:Needles; D018962:Phlebotomy / Q000295:instrumentation / Q000379:methods*; D012333:RNA, Messenger / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002272:Carcinoembryonic Antigen; D012333:RNA, Messenger