I know the ng means nanogram

But I’m curious how would I say the above line of 2.1 ng/kg

For context I got it from this paragraph

a lethal dose of 1.3–2.1 ng/kg in humans

Would it be

2.1 nanogram per kilogram?

Also if I wanted to write that as a decimal number how would i write that?

  • RightHandOfIkaros@lemmy.worldEnglish
    41·
    4 months ago

    “A lethal dose of one point three to two point one (or one and three tenths to two and one tenth) nanograms per kilogram in humans.”

    • andrewta@lemmy.worldOP
      11·
      4 months ago

      So are they saying nanograms of the stuff per kilograms of the human?

      In other words are they saying it’s a ratio compared to the weight of the person?

      • RegalPotoo@lemmy.worldEnglish
        3·
        4 months ago

        Yeah - the dose is the poison (if you drink enough water it becomes toxic), so if you are talking precisely you need to describe the concentration of a substance in which it is likely lethal to a person, and that’s typically expressed as mass of a substance per mass of bodyweight. A lot of the time you will also see this expressed as an “LD50” value; the dose at which you’d expect 50% of people to die. This accounts for the fact that people’s metabolisms vary quite widely.

        ~1ng/kg ~= 0.08ug for a typical (~80kg) person, which is a very tiny amount - whatever you are talking about is incredibly toxic.

  • AmidFuror@fedia.io
    201·
    4 months ago

    You can say “nanograms per kilogram.” You could shorten it to “nanograms per kilo.”

    If it were mg/kg, you could say “migs per kig.” You won’t trick me into saying the equivalent for nanograms, though.

    Edit: Not sure what you mean by how to write it as a decimal number. It’s 0.0000000021g per kg. It wouldn’t be standard to give just a ratio of like mass to mass because as others have written it is mass of substance vs mass of patient.

      • antlion@lemmy.dbzer0.com
        1·
        4 months ago

        Yeah it’s typically not used for dosages, rather it’s for concentrations in solution. However strictly speaking the grams cancel in the units of ng/kg and you are left with ppt. I think of ppm and ppt as very small percentages anyway. As per cent means part per one hundred. Can’t use “permille” because it means part per thousand but sounds like part per million.

        In the case of a lethal dose, I think it would be fine to say, “it’s lethal at a rate of 2 trillionths of body mass”.

  • Paragone@lemmy.world
    51·
    4 months ago

    0.0000000021g/kg

    or 0.0000000000021kg/kg, if you wanted the same units both sides…

    ( I’m presuming this was your last-line’s request )