What do you multiply by to convert from milligrams per deciliter to millimoles per liter?

To convert from milligrams per deciliter (mg/dL) to millimoles per liter (mmol/L), one must use the molecular weight of the substance in question. The conversion factor is based on the relationship between these units.

In this case, multiplying by 10 is correct because one deciliter is equivalent to 0.1 liters. Therefore, when converting mg/dL to mmol/L, the initial units in mg/dL need to be adjusted to reflect the entire liter (1000 mL) rather than just 100 mL (which is what a deciliter represents). When this adjustment is applied, the appropriate multiplication factor for the conversion—factoring in the molecular weight of the substance being measured—effectively becomes 10 in many common cases, especially for certain glucose and cholesterol calculations.

Ultimately, understanding the specific molecular weight of the analyte will dictate the final conversion factor, but for common clinical analytes, multiplying by 10 provides a quick reference for this conversion. This understanding is crucial in clinical chemistry for accurately interpreting laboratory results.