Methadone-Associated Mortality:
Report of a National Assessment

Appendix 5. Methadone Serum Level Conversion Factors

In the literature, there does not appear to be a universally accepted standard for expressing the concentration of methadone (or other agents) detected in the blood of living or deceased subjects, and authors have used diverse measures of notation. Nanograms per milliliter (ng/mL) seems to be the accepted convention in the United States addiction treatment literature; therefore, all values noted in this report have been converted to that measure using the following factors:

Unit 1.0
deci- d 1 x 10^-1 0.1
centi- c 1 x 10^-2 0.01
milli- m 1 x 10^-3 0.001
micro- _ 1 x 10^-6 0.000001
nano- n 1 x 10^-9 0.000000001

_g/L - 1 _g/L = 1000 ng/1000 mL = 1 ng/mL

_g/mL - 1 _g/mL = 1000 ng/mL
(1 ng/mL = 0.001 _g/mL)

mg/L - 1 mg/L = 1000 ng/mL
(1 ng/mL = 0.001 mg/L)

mg/dL - 1 mg/dL = 10,000 ng/mL
(1 ng/mL = 0.0001 mg/dL)

mg% - 1 mg% = 1 mg/100 mL = 10,000 ng/mL
(1 ng/mL = .0001 mg%)

_mol - 1 _mol = 345 ng/mL
(1 ng/mL = 0.0029 _mol = 2.9 mmol
specific to methadone molecular weight)