According to the FDA, heparin strength per total volume should be the primary and prominent expression on the manufacturer's label, followed by the:

This expression indicates the concentration of the heparin solution but is not prioritized after the total strength on the label. While it provides useful information about the solution's composition, it is less relevant to immediate dosing needs than the strength per mL, which healthcare professionals require for administering the correct dose.

This measurement does not represent a standard labeling requirement for heparin. It could imply a ratio but does not provide the necessary information regarding how much heparin is contained in a specific volume, which is critical for medical use. Therefore, it does not qualify as a secondary labeling expression recommended by the FDA.

While this may indicate how much volume is typically administered, it is not the preferred secondary expression according to FDA guidelines. The focus is on the specific strength per mL, which is more pertinent for healthcare providers who need to calculate the exact dosage based on patient requirements.