Evaluation of the dried blood spot (DBS) collection method as a tool for detection of HIV Ag/Ab, HBsAg, anti-HBs and anti-HCV in a Malaysian tertiary referral hospital.
BACKGROUND
Dried blood spot (DBS) collection is an appealing alternative to whole blood or plasma sampling, as it has technical and economic advantages over the latter.


METHODS
A prospective cross-sectional study was conducted at a Malaysian tertiary referral hospital from November 2009 to March 2010. One hundred and fifty paired specimens of DBS and plasma were analysed by the standard assays for HIV Ag/Ab, HBsAg, anti-HBS and anti-HCV, separately (total 600 paired specimens). DBS sample titres were then compared to the results of plasma testing, which was used as the gold standard.


RESULTS
For the HIV Ag/Ab assay with a cut-off point of 0.35 Relative Light Units (RLUs), the sensitivity and specificity were both 100%. For the HBsAg assay, the sensitivity was 96.5% and the specificity was 97.8%, with a cut-off point of 1.72 RLUs. Sensitivity for the anti-HBs test was 74.2% and the specificity was 86.9%, using a cut-off point of 0.635 RLUs. For the anti-HCV assay, the sensitivity was 97.3% and the specificity was 100%, with a cut-off point of 0.10 RLUs.


CONCLUSIONS
DBS is an ideal choice to be used as a screening tool for the detection of HIV, Hepatitis B and Hepatitis C virus infections. However, different cut-off values need to be used for the validation of test positivity in DBS samples because the small amount of blood in the DBS specimens leads to lower assay titres.
Infectious Diseases Unit, University Malaya Medical Centre, Kuala Lumpur. leecheeeng@gmail.com
Chee Eng
CE
Lee
Sasheela
S
Sri Ponnampalavanar
Sharifah Faridah
SF
Syed Omar
Sanjiv
S
Mahadeva
Lai Yee
LY
Ong
Adeeba
A
Kamarulzaman
D003430:Cross-Sectional Studies; D059788:Dried Blood Spot Testing; D015483:HIV Antibodies / Q000097:blood* / Q000276:immunology; D015488:HIV Antigens / Q000097:blood* / Q000276:immunology; D015658:HIV Infections / Q000175:diagnosis*; D016174:Hepacivirus / Q000302:isolation & purification*; D006509:Hepatitis B / Q000175:diagnosis*; D006510:Hepatitis B Antibodies / Q000097:blood* / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000097:blood* / Q000276:immunology; D006526:Hepatitis C / Q000175:diagnosis*; D018937:Hepatitis C Antibodies / Q000097:blood* / Q000276:immunology; D018936:Hepatitis C Antigens / Q000097:blood* / Q000276:immunology; D006801:Humans; D008296:Malaysia; D010949:Plasma / Q000821:virology; D011446:Prospective Studies; D012017:Referral and Consultation; D012680:Sensitivity and Specificity; D013048:Specimen Handling
D015483:HIV Antibodies; D015488:HIV Antigens; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D018937:Hepatitis C Antibodies; D018936:Hepatitis C Antigens