Penicillin allergy test
1. Mechanism of occurrence
Penicillin is a semi-antigen, after entering the human body and tissue protein binding to become a full antigen, stimulate the body to produce specific antibodies (LgE), so that the body is in a sensitized state (sensitization stage). When the body receives penicillin again, the antigen and antibody combine to trigger an allergic reaction (sensitization stage), resulting in a series of allergic reactions such as urticaria, asthma, laryngeal edema, shock and other clinical manifestations.
2. Preventive measures
(1) Before using penicillin, ask the patient in detail about the history of medication, allergy, and family history, and those who have a history of penicillin allergy are prohibited from doing allergy tests and contacting the doctor to change to other drugs.
(2) Allergy test must be done before using various dosage forms of penicillin. Patients who have been treated with penicillin and stop taking the drug for more than 3 days or change the manufacturer or batch number in the process of using the drug must do the allergy test again.
(3) The correct implementation of penicillin allergy test: accurate preparation of skin test solution, the correct implementation of intradermal injection, timely observation of the reaction, the correct judgment test results.
(4) If the test result is negative, the drug can be used; if the test result is positive, penicillin is prohibited, and "penicillin (+)" is marked in red pen on the temperature list, medical prescription list, clinic card, medical record card, injection card and bedside card, and the patient and his family are informed at the same time.
(5) Penicillin should be used now: the aqueous solution of penicillin is very unstable at room temperature, and it is easy to produce penicillinenoic acid, penicillin thiazole and other degradation products and polymer polymers, so that its allergenicity increases, and the efficacy of the drug decreases. Therefore, the use of penicillin should be temporarily prepared, should not be placed too long.
(6) Strengthening work responsibility: staff must strictly implement the checking system. It is not advisable to carry out skin test or administration of drugs on an empty stomach to prevent hypoglycemic reactions from being confused with allergic reactions. The injection of penicillin at the same time to do a good job of rescue preparations, injection after close observation of the patient's reaction, the first injection of penicillin need to be observed for 30 minutes.
3. Test method
Intradermal injection test method
Test solution preparation: test solution containing penicillin G 200-500U per milliliter (200-500U/ml) as the standard, isotonic saline as a diluent preparation, to penicillin 1 bottle of 800,000U as an example (indicated 16-14). Penicillin test solution is unstable and can be stored at room temperature for 4 hours and refrigerated in the refrigerator for 24 hours; it should be discarded when out of date.
Indicates 16-14 penicillin test solution preparation method
Penicillin
Add isotonic saline
Penicillin content
Requirements
800,000 U
4 ml
20U/ml
Completely dissolved
Take 0.ml of the upper liquid
0.9 ml
2U/ml
Shake well
Take 0.1 ml of the upper liquid
0.9 ml
2,000U/ml
Shake well
Take 0.1~0.25 ml of the upper liquid
0.9~0.75 ml
200~500U/ml
Shake well
Test method: Intradermal injection of penicillin test solution 0.1 ml (containing penicillin G20~50U) into the lower part of the palmar side of the forearm, and then observe the result and record it after 20 minutes.
Results judgment:
Negative: no change in the dermal mound, no redness or swelling around it, and no self-conscious symptoms.
Positive: localized elevation of the dermatome, the appearance of redness and hardness, diameter greater than 1cm or pseudopods around the dermatome, itchy feeling. In severe cases, there may be dizziness, panic, nausea, and even anaphylactic shock.
Penicillin rapid allergy test method
Principle:Penicillin molecular structure of the acid root is negatively charged, in the aqueous solution after ionization, the negative ions containing allergen. When energized, its negative ions can penetrate into the subcutaneous through the negative pole, and the body protein binding into antigen, penicillin allergy in the electrode plate under the skin has a positive reaction phenomenon.
Use: Penicillin rapid allergy tester (as shown in the picture), skin test solution (prepared with water for injection) 10000U/ml, water for injection, cotton swabs, gauze.
Test method:
1Connect to the power supply, press the power button, display "123" instrument into the program self-test state; there are faults in the sound and light, the code display alarm, no fault display "P", A, B road (can be done at the same time as two) into standby mode. people) into standby mode.
2 with a swab of water for injection to wipe the patient's forearm often side of the lower part of the skin (avoid using ethanol), should not be too wet.
3 the skin test solution drops on the square electrode cloth, body injection water drops on the round electrode cloth (can be done at the same time the control test), will be fixed band in the skin test site, tighten and loosen the appropriate. Press the "start" button, 5 minutes the instrument displays "FFF" and beep prompt, press the "reset" button, enter standby mode.
4Unbuckle the fixation strap and observe the skin reaction at the electrode indentation.
Judgment by results:
Negative: skin test always without any sensation, drops of liquid under the electrode, even if there is skin pressure or congestion, congestion can be disappeared in 1-2 minutes, no systemic discomfort, or square, round electrodes under the skin have a slight redness, no pimples, not accompanied by local and systemic reactions.
Positive: under the electrodes of drug drops, the skin appears dense small papules or hives, hives, large papules, surrounded by congestion or no congestion, a few patients can be out of the Rui white spots. Some patients are accompanied by arm itching, stinging, pressure and other sensations or have a systemic reaction.