µg/mL\text{µg/mL}

microgram per millilitre

Mass concentrationexact by definition

One microgram in one millilitre, which is numerically the same as one milligram per litre. It is the biochemistry and microbiology form — protein assays, antibiotic potencies and cell-culture supplements are written this way because the volumes handled at a bench are millilitres rather than litres.

Watch out: µg/mL and mg/L are the same number, and the two are used side by side in the same laboratory without comment. That is genuinely safe. The dangerous neighbour is µg/L, which is a thousand times smaller and only one character different in writing.

1 µg/mL\text{µg/mL} 1 mg/L\text{mg/L}

One microgram per millilitre in every mass concentration unit

1milligram per litre (mg/L)
1,000microgram per litre (µg/L)
0.001gram per litre (g/L)
1microgram per millilitre (µg/mL)this unit
0.1milligram per decilitre (mg/dL)
0.0001gram per decilitre (g/dL)
0.001kilogram per cubic metre (kg/m³)
1,000nanogram per millilitre (ng/mL)