HBV DNA IU/mL to Copies/mL Converter
HBV DNA IU/mL to Copies/mL Converter
Convert HBV DNA between IU/mL and copies/mL using an assay-specific factor, and see the log value guidelines are written against.
HBV DNA IU/mL to Copies/mL Converter
IU/mL → log₁₀ copies/mLHBV DNA 2,000 IU/mL, conversion factor 5.26 copies/IU
Formula
log₁₀ copies/mL = log₁₀(copies/mL)
- conversion factor
- assay-specific — commonly about 5.26 copies per IU for the Roche COBAS assay, but ranging roughly 3.4 to 5.8 across platforms
- 2,000 IU/mL
- separates the inactive carrier state from HBeAg-negative chronic hepatitis B
- 20,000 IU/mL
- the corresponding treatment threshold in HBeAg-positive chronic hepatitis B
Worked example
HBV DNA 2,000 IU/mL, conversion factor 5.26 copies/IU
2,000 × 5.26 = 10,520 copies/mL
log₁₀(10,520) = 4.02 log₁₀ copies/mL
Key IU/mL thresholds
| IU/mL | log₁₀ IU/mL | Significance |
|---|---|---|
| 2,000 | 3.30 | Inactive carrier / HBeAg-negative chronic hepatitis B threshold |
| 20,000 | 4.30 | Treatment threshold in HBeAg-positive chronic hepatitis B |
| Undetectable | — | Target of nucleos(t)ide analogue therapy |
Why the same result has two numbers
HBV DNA was historically reported in copies/mL, and different assays used different — often unstated — conversions between the genome copies actually counted and the number reported. The WHO international standard put results on a common IU/mL scale, and that is what current guidelines and treatment thresholds are written against.
The conversion between the two is assay-specific rather than fixed: commonly around 5.26 copies per IU for the Roche COBAS TaqMan assay, but ranging roughly 3.4 to 5.8 across platforms. Because there is no single universal factor, the factor is an input here rather than a constant baked into the calculator — use the value published for the assay that produced the result.
Two thresholds are worth knowing in IU/mL. A level below 2,000 IU/mL, together with a normal ALT and HBeAg-negative status, is consistent with the inactive carrier state; above it defines HBeAg-negative chronic hepatitis B. In HBeAg-positive disease the treatment threshold is 20,000 IU/mL. Both are guideline cut-offs written in IU/mL, not copies/mL.
The rule worth repeating is this: never compare a copies/mL result from one laboratory with an IU/mL result from another without knowing both conversion factors — the discrepancy can be several-fold and can be mistaken for a real change in viral replication.
Frequently asked questions
Why are there two units for HBV DNA?
Older assays reported copies/mL using assay-specific, often unpublished conversions. The WHO international standard introduced IU/mL as a common scale, and current guideline thresholds are written in IU/mL.
What is the conversion factor from IU/mL to copies/mL?
It is assay-specific, not fixed — commonly around 5.26 copies per IU for the Roche COBAS assay, but ranging roughly 3.4 to 5.8 across platforms. Use the factor published for the assay that produced the result.
What HBV DNA level triggers treatment?
2,000 IU/mL separates the inactive carrier state from HBeAg-negative chronic hepatitis B, while 20,000 IU/mL is the corresponding threshold in HBeAg-positive disease. Both figures are in IU/mL.
Can I compare a copies/mL result with an IU/mL result?
Only if you know the conversion factor for both assays. Comparing them directly, or assuming a single universal factor, can produce an apparent change that is really just an assay difference.
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References
- EASL Clinical Practice Guidelines on the management of hepatitis B virus infection. J Hepatol. 2017;67(2):370–98.
- WHO. Guidelines for the prevention, care and treatment of persons with chronic hepatitis B infection.