There are two main methods of describing concentrations: by weight, and by molecular count. Weights are in grams, molecular counts in moles. (If you really want to know, a mole is 6.022*10^23 molecules.) In both cases, the unit is usually modified by milli- or micro- or other prefix, and is always “per” some volume, often a liter.
This means that the conversion factor depends on the molecular weight of the substance in question.
mmol/l is millimoles/liter, and is the world standard unit for measuring glucose in blood. Specifically, it is the designated SI (Systeme
International) unit. “World standard”is not universal; not only the US but a number of other countries use mg/dl. A mole is about 6*10^23 molecules; if you want more detail, take a chemistry course.
mg/dl (milligrams/deciliter) is the traditional unit for measuring Blood Glucose (blood glucose). All scientific journals are moving quickly toward using mmol/L exclusively. mg/dl won’t disappear soon, and some journals now use mmol/L as the primary unit but quote mg/dl in parentheses, reflecting the large base of health care providers and researchers (not to mention patients) who are already familiar with mg/dl.
Since m.h.d is an international newsgroup, it’s polite to quote both figures when you can. Most discussions take place using mg/dl, and no one really expects you to pull out your calculator to compose your article. However, if you don’t quote both units, it’s inevitable that many readers will have to pull out their calculators to read it.
Many meters now have a switch that allows you to change between units. Sometimes it’s a physical switch, and sometimes it’s an option that you can set.