If you are tossing a quantity of inventory out due to it expiring, going bad, or getting lost. For good record keeping, you will navigate to Left Navigation > Inventory > Inventory Management > Search for the Item > Edit the Inventory Item under Inventory Management, and lower the "On Hand" by the amount you are throwing out. Then you can enter a comment in the "Reason for Change" box/field as to the reason. Example: "50 were tossed due to expiration", or a comment relating to that change. Whatever you enter in the comment will appear in the "On Hand Change Report" for that entry.
To record/track wastage when dispensing there is a waste amount on individual treatment items, which is located on the patient's medical record, or quick invoicing page. Once the item is invoiced, click on the items name from treatment page and the "Items Details" page will expand.
Example: If you are administering 2.5 and there is .5 wastage, then the quantity field should be 3, and the wastage field should be .5