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• Antigen Laboratories, Inc.
  

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  Cricket | Antigen Laboratories, Inc.

  

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  Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Some allergenic extracts naturally precipitate. This allergenic extract is "For Diagnostic Use Only". (Refer to STORAGE section.)

  PRICK-PUNCTURE TESTING: To identify highly sensitive individuals and as a safety precaution, it is recommended that a prick-puncture test using a drop of the extract concentrate be performed prior to initiating very dilute intradermal testing. Prick-puncture testing is performed by placing a drop of extract concentrate on the skin and puncturing the skin through the drop with a small needle such as a bifurcated vaccinating needle. The most satisfactory sites on the back for skin testing are from the posterior axillary fold to 2.5 cm from the spinal column, and from the top of the scapula to the lower rib margins. The best areas on the arms are the volar surfaces from the axilla to 2.5 or 5 cm above the wrist, skipping the anticubital space. Skin testing should include a positive control of histamine phosphate and a negative control of 50% v/v glycerine in buffered saline. A positive reaction is approximately 10-15 mm erythema with 2.5 mm wheal. Smaller, less conclusive reactions may be considered positive in conjunction with a definitive history of symptoms on exposure to the allergen. Less sensitive individuals can be tested intradermally with an appropriately diluted extract (See "INTRADERMAL TESTING").

  INTRADERMAL TESTING: The surface of the upper and lower arm is the usual location for skin testing. A sterile, disposable syringe and needle is used for each extract tested. Intracutaneous test dilutions, five-fold or ten-fold, may be prepared from stock concentrate using physiologic saline as a diluent. (1) Start testing with the most dilute allergenic extract concentration. (2) A volume of 0.02-0.05 ml should be injected slowly into the superficial skin layers making a small bleb (superficial wheal). (3) For patients without a history of extreme sensitivity, or a negative or weakly reactive prick-puncture test, the initial dilution for skin testing should be at least 1:12,500 w/v. This initial dilution can be prepared by diluting 1:20 to 1:50 w/v (2%-5%) extracts five-fold to 5-4 or 1:10 w/v (10%) extracts to 5-5. Dilute 1:10 w/v (10%) extracts to 10-3 if using ten-fold dilutions. (4) Sensitive patients with a positive prick-puncture test require a further dilution to at least 1:312,500 w/v. This dilution can be prepared by diluting 1:20 to 1:50 w/v (2%-5%) extracts to 5-6 or 1:10 w/v (10%) extracts to 5-7 (five-fold dilutions). Ten-fold dilution to 10-6 of a 1:10 w/v (10%) extract would be a safe starting dilution. For interpretation of skin reactions, refer to chart below. If after 20 minutes no skin reaction is observed, continue testing using increasing increments of the concentration until a reaction of 5-10 mm wheal and 11-30 mm erythema is obtained, or a concentration of 5-2 or 10-1 has been tested. A negative control, 50% glycerine diluted with diluent to 5-2 (1:25) or 10-1 (1:10) dilution and a positive control of histamine phosphate, should be tested and included in interpretation of skin reactions.2,4

  GRADE mm ERYTHEMA mm WHEAL 0 less than 5 less than 5 ± 5-10 5-10 1+ 11-20 5-10 2+ 21-30 5-10 3+ 31-40 10-15 or with pseudopods 4+ greater than 40 greater than 15 or with many pseudopods

  INTRADERMAL TESTING–SKIN ENDPOINT TITRATION: The allergenic extracts to which the patient is sensitive and the patient's degree of sensitivity can be determined through the use of intracutaneous skin tests involving progressive five-fold dilutions of allergenic extracts. Intracutaneously inject 0.01 to 0.02 ml of the test allergen to form a 4 mm diameter superficial skin wheal. For patients demonstrating a negative or weakly reactive prick-puncture skin test, an initial screening dilution of 1:12,500 w/v is safe. For patients demonstrating a positive prick-puncture skin test, an initial screening dilution of 1:312,500 w/v is safe (see "Serial Dilution Titration Test Dilutions" chart below).When a sequence of five-fold or ten-fold dilutions of an allergen is injected, the endpoint is determined by noting the dilution that first produces a wheal or erythema (15 minutes after injection) that is 2 mm larger than wheals with erythema produced by weaker, non-reacting dilutions (5 mm negative wheal).

  SERIAL DILUTION TITRATION TEST DILUTIONS APPROXIMATE ALLERGENIC EXTRACT CONCENTRATION RESULTING FROM 1:5 DILUTION Titration Number Dilution Exponent Weight / Volume Allergenic Extract Concentrate 1:50 (2%) 1:40 (2 1/2%) 1:33 1/3 (3%) 1:20 (5%) 1:10 (10%) No. 1 5-1 1:5 1:250 1:200 1:167 1:100 1:50 No. 2 5-2 1:25 1:1,250 1:1,000 1:835 1:500 1:250 No. 3 5-3 1:125 1:6,250 1:5,000 1:4,175 1:2,500 1:1,250 No. 4 5-4 1:625 1:31,250 1:25,000 1:20,875 1:12,500 1:6,250 No. 5 5-5 1:3,125 1:156,250 1:125,000 1:104,375 1:62,500 1:31,250 No. 6 5-6 1:15,625 1:781,250 1:625,000 1:521,875 1:312,500 1:156,250 No. 7 5-7 1:78,125 1:3,906,250 1:3,125,000 1:2,609,375 1:1,562,500 1:781,250 No. 8 5-8 1:390,625 1:19,531,250 1:15,625,000 1:13,046,875 1:7,812,500 1:3,906,250 No. 9 5-9 1:1,953,125 1:97,656,250 1:78,125,000 1:65,234,375 1:39,062,500 1:19,531,250 No. 10 5-10 1:9,765,625 1:488,281,250 1:390,625,000 1:326,171,875 1:195,312,500 1:97,656,250 No. 11 5-11 1:48,828,125 1:2,441,406,250 1:1,953,125,000 1:1,630,859,375 1:976,562,500 1:488,281,250 No. 12 5-12 1:244,140,625 1:12,207,031,250 1:9,765,625,000 1:8,154,296,875 1:4,882,812,500 1:2,441,406,250

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