[Modified guanidine hydrochloride method for DNA extraction from cord blood used in HLA genotyping]

To compare two different methods for extracting genomic DNA from cord blood and to evaluate their applications for HLA genotyping, the genomic DNA from 72 samples was extracted by guanidine hydrochloride (Gu * HCl) and modified guanidine hydrochloride, the DNA yield and purity were evaluated by spectrophotometry and detected by PCR with sequence-specific primers. The result showed that the genomic DNA was successfully isolated from whole blood by both methods. The modified Gu * HCl method used was better than Gu * HCl method as the modified method produces better quality of DNA and less ambiguous bands in PCR. It is concluded that modified Gu * HCl method has the advantages of low-cost, simple operation, high quality output and clear positive bands in HLA-genotyping, the modified method is optimal for extracting DNA from multiple samples of cord blood bank.