Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. The product should be discarded if discoloration or particles are observed.   
The skin test concentration of 10,000 AU/mL in dropper vials is used for scratch or prick-puncture testing. Puncture tests performed with D. farinae extract on 5 persons sensitive to mite showed a mean diameter wheal of 8.8 mm + 1.8 mm and mean diameter erythema of 39.2 mm + 5.3 mm.   
Puncture tests with D. pteronyssinus extract on 10 persons sensitive to mite showed a mean diameter wheal of 7.8 mm + 4.1 mm and mean erythema of 33.7 mm + 12.0 mm.   
Extract for intradermal testing should be prepared by diluting the 10,000 AU/mL stock concentrate in bulk vials with sterile saline with or without human serum albumin.   
Intradermal skin tests (0.05 mL) in persons highly sensitive to mite showed the following results: 

Intradermal extract should be used as follows:   
Intradermal tests should only be performed after a scratch or prick-puncture test has been administered with a negative result. Patients who do not react to a valid scratch or prick-puncture test should be tested intradermally with 0.02 to 0.05 mL of a 10 AU/mL (1:1,000 v/v of the 10,000 AU/mL concentrate). If this test is negative, a second intradermal test may be performed using a 100 AU/mL (1:100 v/v dilution of 10,000 AU/mL concentrate). Skin tests are graded in terms of the wheal and erythema response noted at 1 5 to 20 minutes. Wheal and erythema size may be recorded by actual measurement of the extent of both responses. 

Therapeutic   
The dosage of mite extract administered by subcutaneous injection is highly individualized and varies according to the degree of sensitivity of the patient, his clinical response and tolerance to the extract administered during the early phases of an injection regimen. In patients who appear to be highly sensitive by history and skin test, the initial dose of the extract should be 0.05 mL of a 0.1 AU/mL dilution or as established by skin test titration. The amount of allergenic extract is increased at each injection by not more than 50% - 100% of the previous amount, and the next increment is governed by the response to the last injection. Large local reactions which persist for longer than 24 hours are generally considered an indication for repeating the previous dose or reducing the dose. Any evidence of systemic reaction is an indication for a significant reduction (at least 50%) in the subsequent dose. The upper limits of dosage have not been established; however, doses larger than 0.2 mL of the concentrate may be painful due to the glycerin content of the extract.   
The optimal interval between doses of mite extract has not been definitely established. However, as is customarily practiced, injections are given one or two times per week until the maintenance dose of extract is reached. At this time, the injection interval may be increased to 2 weeks, then to 3 weeks and finally to 4 weeks. If the patient does not return for 6 to 8 weeks after the last injection, the dose should be reduced to 25% of the last dose. If longer than 8 weeks, a dose reduction of one, too or three dilutions may be made depending on a consideration of the components and the patient's sensitivity The dosage and the interval between injections may need to be modified according to the clinical response of the patient. When switching patients to fresh extract, the initial dose should be reduced to one-quarter (25%) of the previous dose.   
The usual duration of treatment has not been established. A period of three to five years of injection therapy constitutes an average course of treatment.   
Children and older age patients appear to tolerate injections of allergenic extract well, and no special recommendations need to be made for these groups. 

Preparing Dilutions   
To prepare dilutions for intradermal skin tests and therapeutic use, the stock concentrate may be diluted as shown in Table 1. Vial #1 is made by adding 1.0 mL of the concentrate to 9.0 mL of sterile diluent. Vial #2 is made by adding 1.0 mL of Vial #1 to 9.0 mL of sterile diluent. This process is repeated until the desired concentration is achieved. In each case, the subsequent vial is made by adding 1.0 mL of the previous dilution to 9.0 mL of sterile diluent. The number of allergy units per mL in each dilution is shown in table below.