Lincoln Diagnostics, Inc.

"Utilizing the three skin testing devices, twenty subjects were tested on the back, four sites with histamine and four sites with saline. Greer Pick produced 52% greater intrasubject variability than UniTest PC, and 46% greater than the smallpox needle. Wheals greater than 3mm at saline sites occurred only from Greer Pick. Neither UniTest PC nor the smallpox needle produced wheals greater than 3 mm at saline sites. The highest sensitivity (100%) was gained from UniTest PC, While the lowest resulted from the smallpox needle (91%). Pain was minimal for all devices, but Greer Pick and the smallpox needle caused sharp pain while UniTest PC created a pressure-like pain. UniTest PC was considered, by the technicians, the easiest to use. Testing technicians observed that periodically a Greer Pick point did not penetrate the epidermis, necessitating repeat pricking."

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"Twenty adult patients were tested, utilizing 1mg/ml histamine on the arms and 6 mg/ml histamine on the back. Multi-test PC produced only three wheals less than 3 mm in diameter on the arm and none on the back, while ComforTen results showed 27 or nine times as many, arm and back. When averaging wheal sizes, wheals from Multi-Test PC were 50% larger than those from ComforTen. ComforTen was 14% more painful than Multi-Test PC."

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Purpose of study:

"To determine whether a skin test (ST) profile of negative percutaneous tests with positive ID [intradermal] tests (-/+ST) correlated with positive nasal challenges (NC)."

Results:

"Of 76 subjects tested using Multi-Test II (MT-II) percutaneous and ID methods with six aeroallergens (alternaria, cat, mixed ragweed, trees, grasses, house dust mites), repeat STs confirmed 8 subjects with 12 -/+ST profiles to an aeroallergen."

"None of the 12 NCs performed in 8 -/+ST subjects were positive."

Conclusions:

"In our study, positive ID tests with corresponding negative MT-II tests did not identify any subjects with a positive NC. These findings indicate that when MT-II tests are negative, routine performance of ID tests is unlikely to identify clinically significant allergy."

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"An important observation from our study is that Multi-Test affords the user greater protection against blood-borne diseases than other skin testing techniques. Its construction and method of application are such that the user's fingers and hands are not in close proximity to any bleeding that might occur on the patient's skin. In addition, the design of Multi-Test and its method of administration greatly reduce the risk of inadvertent pricking of the user's skin."

"We found the Multi-Test technique of skin testing to be rapid, convenient, and well accepted by patients. Reproducibility of test results from Multi-Test was high, and variability of results between users low. We concluded that the Multi-Test technique of skin testing provided sufficient precision, sensitivity, and specificity to be classified as a reliable in-office diagnostic procedure."

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"The reproducibility of the histamine reactions expressed as the standard deviation also revealed significant differences among devices. The variability of the Multi-Test [II] device was significantly less than that of the smallpox needle or the Duotip and DermaPIK by either method as well as the Quintest."

Multi-Test II had the lowest variability of all the devices used (CV = 12.7), including the following:

• Multi-Test II (Avg. combined arm and back) 12.7
• Quintest (Avg. combined arm and back) 26.4
• Smallpox needle (prick) 22.0
• DermaPIK (GreerPIK), prick 19.2
• DermaPIK (GreerPIK), twist 16.9

This study found DermaPIK twist to be traumatic to the skin, evoking substantial non-specific irritant response. DermaPIK twist had low specificity (35%) at a 3 mm wheal cutoff. Every other method, including DermaPIK prick, was at least 95% specific at a 3 mm level. Sensitivity and specificity for Multi-Test II was 100% and 97.5% respectively. [Lincoln Diagnostics' summary]

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"When Multi-Test and Morrow Brown skin test results from antigens on the upper and lower right side of the back were compared with their duplicates on the left side, the correlation between reaction sizes was better with Multi-Test. The Pearson correlation coefficient for the Multi-Test of 0.91 was superior to that of the Morrow Brown needle which was 0.47."

"Finally, when patients were asked which skin test device they preferred, 29 out of 30 chose the Multi-Test. The principal reasons were that it was less painful because it diffused the pain and its quicker application."

"In conclusion, our experiences with Multi-Test, both in routine clinical use and under controlled study conditions, have been highly satisfactory and we have found this technique reliable, convenient and well accepted by patients."

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"Skin testing is rapid and relatively painless. Because such a small quantity of antigen is introduced into the epidermis, the likelihood of an anaphylactic reaction is minimized."

"The Multi-Test device lends itself admirably to the standardization of testing technique, a goal greatly desired in allergy practice. A reasonably uniform amount of glycerinated material is deposited in a constant area of 2mm with penetration limited to the epidermis. Because of the simultaneous and standardized application, reactions to controls and antigens can be meaningfully compared."

"Skin test responses to glycerinated inhalant antigens, 1:20 or 1:10 w/v, administered by Multi-Test were comparable to those obtained from the same antigens applied intradermally in aqueous dilutions of 1:1000 or 1:1500 w/v."

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"The intradermal test was always positive in patients but induced two false positive reactions. All prick test methods gave false negative reactions. The Multi-Test device produced intermediate reactions between prick test and intradermal test."

"Multi-Test gave the best correlations among all four skin tests and specific IgE antibody titers."

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"Allergy skin tests can be very helpful in evaluating chronic rhinitis and should especially be directed to those with an allergy history and/or nasal eosinophilia with or without basophilic cells. A sterile, disposable, multi-head puncture device, MULTI-TEST, provides a convenient, rapid and sensitive technique."

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"To answer the question of whether proximity of Multi-Test skin test sites causes false positive reactions, 50 subjects with prior 4+ skin test responses were retested with antigens and ten additional subjects were tested with histamine (1.8 mg/ml). No positive readings occurred at any of the replicate saline control sites adjacent to 3+ or 4+ allergen sites or to 3+ histamine reactions."

"Our results would indicate that the proximity of test head sites does not contribute to false positive responses, and that those who use Multi-Test may be assured of the immunologic accuracy of positive skin test results."

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"This study demonstrates that percutaneous administration of histamine with a MULTITEST device is a simple, rapid, reproducible method that permits the measurement of dose-related histamine responses in vivo in an acceptably precise manner. This method minimizes the requirement for skill that is known to be essential for reproducible testing by intradermal or needle-prick methods."

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"The Multitest holds a standard amount of antigen and when applied according to manufacturer's directions produces a uniform depth of puncture."

"The reproducibility of Multitest was evaluated by one investigator on 33 patients. Data are shown in Table III. The total percentage agreement was 85%, which may be considered excellent for this type of procedure. The percentage agreement could have been much higher had the criteria not been so stringent."

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"In relation to other forms of skin testing, Multi-Test enjoys advantages such as speed, convenience, and good patient acceptance. When using Dip 'N Touch for loading heads, dozens of antigens can be applied to a patient's back or arms in a reproducible fashion very quickly."

"While rapid and convenient, it shares the advantages of intracutaneous testing that include a high level of sensitivity (comparable to that of intracutaneous testing with 1:1000 dilution of antigens wt/vol) and a comparable level of reproducibility. Further, Multi-Test is particularly adaptable for standardization of antigen application, interpretation of reactions and scoring, an attribute that is increasingly important in modern practice."

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"Thirty-six subjects, 6 males and 30 females, mean age 30.6 years (range 21-60), were skin tested with Multi-Test II and Quintest utilizing histamine (10 mg./ml.) at six sites and glycerosaline at two sites for each device."

"Mean wheal sizes from histamine were: Multi-Test II 7.7 mm, Quintest 5.3. Mean coefficient of variation: Multi-Test II 17.7%, Quintest 36.1%. Sensitivity and specificity at 3 mm. level of positivity: Multi-Test II 97.7% and 95.8%, Quintest 91.2% and 100%."

"For application of 40 tests . . . Quintest testing required 2.9 times more time than did Multi-Test II testing."

"Both devices had high sensitivity and specificity. Multi-Test II had better reproducibility, faster application and better subject acceptance than Quintest . . . The 14.7 cm length of Quintest (versus 6.9 cm length of Multi-Test II) may limit its usefulness in smaller subjects and children."

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