Hepatitis C update
HCV- RNA by branched DNA and PCR
Due to the daily fluctuations in the viral load, recent studies have shown that success of antiviral
therapy depends on the viral load estimation by branched DNA. Quantitation should be performed
before starting therapy then at three and twelve months during therapy in order to modify therapy
accordingly. Treatment is considered successful if HCV-RNA by branched DNA is below
< 3,200 copy / ml and HCV-RNA by PCR is negative. However; complete success of therapy cannot
be guaranteed unless HCV positive strands in mononuclear cells & HCV in liver biopsy are also negative.
Branched DNA is a reliable standardized procedure that does not give false negative results.However,
this methodology cannot diagnose a viral load below < 3,200 copy / ml. Thus branched DNA results
should not be reported as negative without a negative PCR result.
HCV-RNA by PCR on the other hand is more sensitive hence can detect a viral load
below < 3,200 copy / ml. In addition, PCR is more sensitive than branched DNA in diagnosing
the very early phase of HCV infection.
Both procedures are available in our lab to reach a conclusive diagnosis.
HCV positive strands in Mononuclear cells
Organs other than the liver such as peripheral blood mononuclear cells can act as a
reservoir for HCV infection.
Such a reservoir can be detected by the HCV positive strand test.
HCV negative strands in Mononuclear cells
HCV negative strands on the other hand denote HCV replication hence the need to
continue therapy.
HCV genotype and subtype
Typing of hepatitis C is clinically important because some genotypes do not respond to
interferon therapy ; in addition typing is of prognostic value since some genotypes develop
chronic hepatitis, cirrhosis and or hepatocellular carcinoma faster than others.
Patients who have undergone liver transplantation or are HCV positive strand should also
be typed to point out those who may become reinfected and develop chronic liver disease or
cirrhosis in the new graft.
HCV- RNA in liver biopsy
Liver biopsy is essential in determining the presence of fibrosis or cirrhosis as well as the
degree of inflammatory changes.
There is no specific histochemical stain for hepatitis C virus, hence the only accurate method to
demonstrate presence of the virus in the liver is by In Situ Hybridization (ISH).
This test is particularly useful in patients who are seronegative yet the virus may still be present
and replicating in the hepatocyte.
RIBA or LIA
To confirm the positive HCV IgG results .
HEPATITIS C : CHOOSING THE RIGHT TEST
Diagnosis of: HCV infection
– History of risk factors such as blood transfusion.
– Clinical signs & symptoms of liver disease.
– Liver enzymes. Total bilirubin, Prothrombin time & Alkaline Phosphatases .
– Early phase of infection : HCV-RNA by PCR + HCV IgM & IgG .
– Ongoing infection HCV-IgG & HCV IgM + HCV-RNA by PCR.
Therapy :
HCV genotype & subtype.
HCV-RNA by branched DNA.
Successful therapy :
HCV-RNA by branched DNA : below < 3,200 copy / ml.
HCV-RNA by PCR : negative.
HCV positive strands : negative.
HCV in liver biopsy by ISH : negative.
