Human herpesviruses 6 (HHV-6), 7 (HHV-7) and 8 (HHV-8) are lymphotropic herpesviruses that may cause opportunistic diseases in immunosuppressed patients such as transplant or AIDS patients. The new commercial CMV HHV-6, 7, 8 R-gene kit (Argene, Varilhes, France) for the simultaneous quantitation of HHV-6 and qualitative detection of HHV-7 and HHV-8 was evaluated using whole blood samples (respectively, n=175, 100 and 161) and using different extraction and real-time PCR platforms in two Centers A and B. In comparison with HHV-6 in-house real-time PCR the commercial kit showed agreements of 96% (n=75) and 85% (n=100) in A and B, respectively, with significant Spearman's correlation between both techniques (in A: r=0.97 [p<0.001]; in B: r=0.70 [p<0.001]). The Bland-Altman test results and prospective monitoring of patients confirmed the accuracy of these HHV-6 real-time PCR techniques. The agreement between the in-house HHV-7 PCR and commercial kit was of 86% (n=100). In comparison with in-house HHV-8 real-time PCRs, the commercial kit showed agreements of 100% (n=61) and 93.7% (n=96) in A and B, respectively. These results demonstrate that the new commercial CMV HHV-6, 7, 8 R-gene kit was an efficient and reliable tool for the diagnosis of herpesvirus 6, 7, 8 infections.