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Three Part Question

In [any person who has had a needlestick injury] is [an anti-HCV antibody test more sensitive than a HCV-RNA test] at [detecting those with HCV].

Clinical Scenario

A distressed young man came into the emergency department with a needlestick injury which he had sustained from a known hepatis C source who was also an intravenous drug user. We wondered if HCV-RNA PCR is more sensitive test than anti-HCV antibody test at detecting HCV.

Search Strategy

Medline 1966-July 2006 using the OVID interface.
[blood exposure.tw or needlestick$.tw or needle?stick.tw or EXP needlestick injuries/] AND [hepatitis C adj management or HCV adj treatment$ or HCVadj RNA or HCVadj PCR or ELISA adj HCV or immunoblot adj HCV]
Search limited to english and human studies

Search Outcome

152 papers found, 6 papers relevant ,4 papers used

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Bossi et al 2004 Italy	Unselected serum and plasma specimens referred to the virology laboratory for HCV-RNA between 1997-2000	Diagnostic study	Qualitative HCV-RNA determination compared with 2 types of	888 samples were assayed, 579 (65.2%) were +ve for HCV-RNA, anti-HCV was detected in 802 sera by MEIA (90.3%) and in 783 by immunoblot (706 +ve and 77 indeterminate, 88.2%). The anti-core antibodies displayed the best correlation with viraemia i.e. 97.1% of the PCR+ samples, followed by anti-NS3 (90.2%) and anti-NS4 (89.6%). Only one +ve HCV-RNA was –ve by immunoblot and MEIA (early seroconversion	Small no. of samples to verify the overall specificity of MEIA
Wang TY et al 2002 China	14 subjects following needlestick injury in which the source patients were +ve for both anti-HCV and HCV-RNA	Prospective diagnostic study	Use of HCV-PCR instead of an anti-HCV test for earlier and more effective detection of HCV	Out of the 14 incidence of subjects exposed to HCV following NSI from HCV +ve sources, they were all negative for anti-HCV at the time of incident. In one of the exposed subjects, a nurse, the result of HCV-PCR was +ve at 2 weeks after the NSI. The nurses viral load was very low (800 copies/ml) and she responded well to immediate treatment and never developed acute HCV. Her anti-HCV did not become elevated and results for RNA-PCR were negative following treatment. In the other 13 NSI, the results of PCR tests were negative for HCV-RNA throughout the study	Small sample size
Hitzler WE et al 2001 Germany	Blood donations over 4 yrs were screened for HCV-RNA using two commercial HCV-PCR kits	Diagnostic study	The feasibility and efficacy of routine screening of blood donations for HCV-RNA	251,737 blood donations were screened over 4 yrs by pool testing. With a maximum pool size of 40 serum samples. 3 donations out of 251,737 were HCV-RNA +ve and anti-HCV negative. The HCV infection of a fourth HCV-RNA +ve donor could not be identified by routine 2nd generation HCV EIA. Two previous donotions were also HCV-RNA +ve but the enzyme immunoassay screening test systems could not detect anti-HCV
Garinis G et al 1999 Greece	161 haemodialysis (HD) patients, mean age 43.3 range 25.3-61.83, 83 males and 78 females were examined 3 times over 1.5 yrs	Diagnostic study	To compare the anti-HCV and HCV-RNA screening results using ELISA III and qualitative RNA-PCR respectively. All samples were then confirmed by RIBA 3rd (Recombinant immunoblot 3rd generation assay)	161 HD pts were anti-HCV tested by the ELISA III and confirmed by RIBA 3rd. HCV-RNA was determined by PCR. Reported results obtained from ELISA III and PCR assays were HCV +ve for 16/161 pts (9.93%).These 16/161 were subsequently confirmed by the RIBA 3rd. For three individuals anti-HCV(-)/RIBA(+)/HCV RNA(-),the viral load was less than the assay detection level (<2,000 viral copies/ml)	Comparison of the enyme-Linked Immunosorbant Assay III, Recombinant Immunoblot 3rd Generation Assay, and PCR method in the detection of HCV infection in haemodialysis patients. Journal of Clinical Laboratory Analysis. 13:122-125 (1999)

Comment(s)

The laboratory diagnosis of HCV is based on the detection of antibodies and viral RNA. Antibody detection is performed using screening tests (enzyme immunoassays) e.g MEIA screening assay or supplemental assays (immunoblots). Antibodies however, can appear late during seroconversion, and their significance is limited to confirm that an actual contact with the virus has occurred. Even the examination of antibodies directed against individual proteins that is usually performed using many commercially available supplemental assays, does not give any significant diagnostic or prognostic information unless it is repeated over time (Bossi et al 2004). The detection of the virus genome (HCV-RNA), using nucleic acid amplification assays, such as PCR, can therefore be more significant.

Clinical Bottom Line

Both anti-HCV and HCV-RNA should be used to test for HCV following needlestick injury because anti-HCV is not always detected in some patients until 2-8 weeks after onset of symptoms. However HCV-RNA marker can be detected even before the onset of symptoms and lasts through the acute illness.

References

1. Bossi V,Galli C. Quantitative signal of anti-HCV by an automated assay predicts viraemia in a population at high prevalence of hepatitis C virus infection. Journal of Clinical Virology. 30 (2004) : p45-49
2. Wang TY. Kuo HT. Chen LC. et al. Use of polymerase chain reaction for early detection and management of Hepatitis C virus infection after needlestick injury. Annals of Clinical & Laboratory Science. 32(2):137-41, 2002
3. Hitzler WE, Runkel S. Routine HCV PCR screening of blood donations to identify early HCV infection in blood donors lacking antibodies to HCV. Transfusion. Volume 41, March 2001
4. Garinis G. Spanakis N, Theodorou V et al. Comparison of the enyme-Linked Immunosorbant Assay III, Recombinant Immunoblot 3rd Generation Assay, and PCR method in the detection of HCV infection in haemodialysis patients. Journal of Clinical Laboratory Analysis. 13:122-125 (1999)