HBV DNA Quantification: Results from the UK NEQAS Proficiency Panel

HBV DNA quantification Monitor active infection Monitor patients response to therapy Infectivity of Health Care Workers

Challenges Specimen preparation Dynamic range of assays Units Scoring Participants diluting specimens

Dynamic ranges of HBV DNA commercial assays

Stability Two freeze-dried specimens consisting of Q1, a neat specimen and Q2 a 1:100 dilution of Q1. Seven pairs were stored at +40C and tested for HBV DNA levels each month for six months and again at 12 months. A further pair of specimens was stored at room temperature and –300C respectively and tested after 12 months. All testing was performed at Birmingham PHL and tested for HBV DNA viral load using both the automated Cobas and manual Roche Monitor assay. The manual assay had a slightly higher standard deviation than the Cobas assay but all results were within half a log of the mean over the twelve-month period.   The freeze-dried HBV DNA specimens were stable at +40C, room temperature and –300C over a period of 12 months.

Pre-pilot Dist. 1531 Pre-Pilot to UK laboratories N=12

Pilot 1 Dist 1621 (24 data sets)

Pilot 1 Specimens 6568 and 6569 Specimens 6570 and 6571 Median 1 +/- 0.5 log 17 23 +/- >0.5 to 0.75 log +/- >0.75 log 2 Total 20 24 Outlier info

Pilot 2 Dist 1622 35 data sets

Pilot 2 Specimens 6572 and 6573 Specimens 6574 and 6575 Median 2 1 +/- 0.5 log 29 20 +/- >0.5 to 0.75 log +/- >0.75 log 4 3 Total 34 25 Outlier info

HBV DNA Units