title: Commercial real-time reverse transcriptase PCR assays can underestimate or fail to quantify hepatitis delta virus viremia.
abstract: OBJECTIVE
  Hepatitis delta virus (HDV) infection causes fulminant hepatitis and increases the severity of chronic hepatitis B virus infection, leading to cirrhosis, liver failure, or hepatocellular carcinoma. There are 8 HDV genotypes (genotypes 1-8). We previously developed a TaqMan real-time reverse transcriptase (RT)-PCR method that is able to quantify viral load of all HDV genotypes (linear from 2 to 8 log(10) copies/mL). We compared its results with those from 3 commercial real-time RT-PCR assays: the Lightmix HDV kit (designed to quantify HDV genotype 1 [HDV-1]), and the RoboGene and the DiaPro HDV RNA quantification kits (designed to quantify all genotypes).
  
  
  METHODS
  We selected RNA from 128 clinical samples of all HDV genotypes except HDV-4, with various HDV viral load values. We also analyzed 5 samples, collected over time, from each of 6 patients infected with strains of different genotypes.
  
  
  RESULTS
  Quantification results from the commercial kits for HDV-1 from European or Asian samples were consistent with those from our method, however, they underestimated (0.5-1 log(10) with Lightmix and DiaPro) and did not detect (1 and 4 samples with Lightmix and DiaPro, respectively) HDV-1 African samples. Moreover, the commercial kits greatly underestimated HDV viral load of almost all non-genotype-1 strains (about 2-3 log(10)), and even did not detect HDV-7 or HDV-8 RNA in several samples with high concentrations of virus.
  
  
  CONCLUSIONS
  Commercial kits accurately quantify HDV-1 in samples from European and Asian patients. However, they can dramatically underestimate or fail to quantify HDV viral load from samples from African patients infected with strains of genotypes 1 and 5 to 8.
authors: Laboratoire de Bactériologie, Virologie-Hygiène, Hôpitaux Universitaires de Paris Seine Saint Denis, Site Avicenne, Assistance Publique, Hôpitaux de Paris, Laboratoire Associé au Centre National de Référence des Hépatites B, C et Delta, Bobigny.
authors: Ségolène
authors: S
authors: Brichler
authors: Frédéric
authors: F
authors: Le Gal
authors: Afifaa
authors: A
authors: Butt
authors: Sylvie
authors: S
authors: Chevret
authors: Emmanuel
authors: E
authors: Gordien
mesh_terms: D000349:Africa; D001208:Asia; D003951:Diagnostic Errors; D005060:Europe; D005260:Female; D003699:Hepatitis D / Q000175:diagnosis* / Q000821:virology; D003698:Hepatitis Delta Virus / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D019562:Viral Load / Q000379:methods*; D014766:Viremia / Q000175:diagnosis* / Q000821:virology