Dose Calculations for the Maintenance Vial
Theformulabelowoffersasimpliﬁedmethodforcalculatingthevolumeofan extract to add based on the target dose selected. Importantly, thiscalculationcanbeusedforanypotencyunit(AU, BAU, PNU, w/v, or µg).
V = 10T/E
V: Volume to be drawn up from the manufacturer’s bulk concentrate and added to the patient’s vial
T: Target maintenance dose in 0.5cc injection (e.g., 2000BAU, 1000PNU, 7.5µg Der p 1)
The following assumptions are made, and must be met to use this formula:
- (1) The volume of the patient’s maintenance vial to be mixed = 5mL
- (2) The maximum injection volume for the maintenance dose = 0.5cc
This formula is derived from the basic chemical formula for determining volume and concentration:
(V1 x C1 = V2 x C2).
V1 = Target Volume
C1 = Target Concentration V2 = Volume Needed
C2 = Concentration Needed
Forvialsthatfalloutsidetheassumptionsofusinga5mL maintenance vial with a 0.5 cc injection volume, it is best to use the basic chemical formula outlined above.
Timothy Grass (Phleum pratense):
Target concentration (T) = 2000 BAU
Extract Concentration (E) = 100,000 BAU
V = 0.2 mL
House Dust Mites (Dermatophagoides farinae/Dermatophagoides pteronyssinus)
E = 10,000 AU
V = 1 mL