Table 1.
World Health Organization International Standards for Molecular Infectious Disease Testing
| Target | Year established | Assigned value* | Mean assayed value† | Characteristics‡ |
|---|---|---|---|---|
| HCV RNA First International Standard (96/790) | 1997 | 4.70 log10 IU/vial (reconstituted to 0.5 ml) 5.00 log10 IU/ml | 5.0 log10 NAT detectable units/ml | HCV-positive donation; genotype 1; diluted in cryosupernatant; freeze-dried10 |
| HBV DNA First International Standard (97/746) | 1999 | 5.70 log10 IU/vial (reconstituted to 0.5 ml) 6.00 log10 IU/ml | 6.42 log10 equivalents/ml | Single donor material, Eurohep R1; genotype A, HBsAg subtype adw2; diluted in pooled plasma; freeze-dried19 |
| HIV-1 RNA First International Standard (97/656) | 1999 | 5.00 log10 IU/vial (reconstituted to 1.0 ml) 5.00 log10 IU/ml | 4.75 log10 copies/ml in quantitative assays | HIV PCR-positive/antibody-negative plasmapheresis donation; genotype B; diluted in defibrinated plasma; freeze-dried18 |
| HCV RNA Second International Standard (96/798) | 2003 | 4.70 log10 IU/vial (reconstituted to 0.5 ml) 5.00 log10 IU/ml | 5.0 log10 NAT detectable units/ml | HCV positive donation; genotype 1; diluted in cryosupernatant; freeze dried; separate lyophilization of same material as the first HCV IS12 |
| HAV RNA First International Standard (00/560) | 2004 | 4.70 log10 IU/vial (reconstituted to 0.5 ml) 5.00 log10 IU/ml | 5.29 log10 equivalents/ml | HAV-positive donation diluted in HCV-, HAV-, HIV-, HBV and HBsAG-, anti-HCV-, anti-HIV-negative human plasma20 |
| Parvovirus B19 DNA First International Standard (99/800) | 2004 | 5.70 log10 IU/vial (reconstituted to 0.5 ml) 6.00 log10 IU/ml | 5.89 log10 copies/ml | Parvovirus B19-positive donation; diluted in pooled plasma; freeze-dried21 |
| HBV DNA Second International Standard (97/750) | 2006 | 5.70 log10 IU/vial (reconstituted to 0.5 ml) 6.00 log10 IU/ml | 6.30 log10 equivalents/ml | Single donor material, Eurohep R1; genotype A, HBsAg subtype adw2; diluted in pooled plasma; freeze-dried; second aliquot of original preparation19 |
| HIV-1 RNA Second International Standard (97/650) | 2006 | 5.56 log10 IU/vial (reconstituted to 1.0 ml) 5.56 log10 IU/ml | 5.35 log10 copies/ml in quantitative assays; original testing | Field isolate: HIV-1, genotype B env V3, gag; propagated on PBMCs, diluted in pooled human cryosupernatant18 |
| Plasmodium falciparum DNA First International Standard (04/176) | 2006 | 8.7 log10 IU/vial (reconstituted to 0.5 ml) 9.00 log10 IU/ml | 8.51 log10 equivalents/ml | Freeze-dried whole blood patient blood collected by exchange transfusion23 |
| HCV RNA Third International Standard (06/100) | 2007 | 4.89 log10 IU/vial (reconstituted to 0.5 ml) 5.19 log10 IU/ml | Not applicable | Window period anti-HCV-negative plasma, genotype 1a HCV13 |
| HPV type 16 DNA First International Standard (06/202) | 2008 | 6.70 log10 IU/vial (reconstituted to 0.5 ml) 7.00 log10 IU/ml | 1 IU/ml is traceable through calculations to 0.947 GEq/ml, determined by independent methods | Freeze-dried recombinant plasmid containing full-length HPV-16 DNA in a background of purified human genomic DNA22 |
| HPV type 18 DNA First International Standard (06/208) | 2008 | 6.70 log10 IU/vial (reconstituted to 0.5 ml) 7.00 log10 IU/ml | 1 IU/ml is traceable through calculations to 1.031 GEq/ml, determined by independent methods | Freeze-dried recombinant plasmid containing full-length HPV-18 DNA in a background of purified human genomic DNA22 |
HAV, hepatitis A virus; HBV, hepatitis B virus; HBsAg, hepatitis B surface antigen; PMBC, peripheral blood mononuclear cell; HPV, human papilloma virus; GEq, genome equivalents.
*
Concentration is in IU/vial. Some vials are reconstituted only to 0.5 ml.
†
Assayed value given when determined through global collaborative studies or when assayed by independent methods before assignment of IU.
‡
Characteristics and instructions for use are at http://www.NIBSC.ac.uk, last accessed August 20, 2009.