Thank you for your recent inquiry.
First of all, a multitest in strength is usually considered somewhere between a classical prick test (where each antigen is tested separately) and an intradermal test. However, it would, in my opinion, be considered a closer relative to the prick test than to the intradermal test as noted in an abstract copied for you below (Simons JP, et al). Therefore if you are limited to classifying it into either the prick or intradermal category, I would place it within the prick test classification.
There are a number of systems used to grade allergy prick and intradermal testing. The grading system is identical for both. I have copied below two such systems. One is taken from an article in the Annals of Allergy, Asthma, and Immunology and the other from Patterson's textbook of Allergy. These are representative samples and both are very similar.
Alternatively, you could employ the system suggested by the American Academy of Allergy, Asthma, and Immunology which recommends measuring height and width. A form for recording skin test results in this fashion is available online for members of the Academy.
Thank you again for your inquiry and we hope this response is helpful to you.
Otolaryngol Head Neck Surg. 2004 May;130(5):536-44.
Comparison of Multi-Test II skin prick testing to intradermal dilutional testing.
Simons JP, Rubinstein EN, Kogut VJ, Melfi PJ, Ferguson BJ.
Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
OBJECTIVES/HYPOTHESIS: Intradermal dilutional testing (IDT) has been considered more sensitive than prick testing for detecting low-level allergies. Multi-Test II is one of the most sensitive and reproducible prick testing methods available. This study compares Multi-Test II prick testing with IDT.
DESIGN: Retrospective chart review and data analysis on patients who had allergy testing with both Multi-Test II and IDT.
SETTING: Outpatient allergy clinic in the otolaryngology department of an academic tertiary care medical center.
POPULATION: Forty adult patients had complete allergy testing with both Multi-Test II and IDT for a standard panel of twelve antigens between January 2002 and April 2002.
INTERVENTION: Analysis and comparison of test results on Multi-Test II and IDT for each antigen separately and across all antigen tests together.
RESULTS: Forty patients had complete testing for all antigens during the time period for the study. Six of these patients did not react to the positive control on Multi-Test II and were eliminated from the main analysis. Of the 34 patients included in the main analysis, all were positive for at least one antigen on IDT; one half (17/34) were negative for all antigens on Multi-Test II. A significantly greater number of patients were positive on IDT than Multi-Test II for all antigens except dog (P < 0.05). There was a statistically significant correlation between IDT endpoint and Multi-Test II score for several antigens (P < 0.05). Of 408 total antigen tests performed, 339 (83.1%) were negative on Multi-Test II. Of these 339 negative Multi-Test II tests, 148 (43.7%) were negative on IDT and 191 (56.3%) were positive on IDT; 174/339 (51.3%) had an IDT endpoint of 2 or 3 and 17/339 (5.0%) had an IDT endpoint > or = 4. A significantly greater number of antigen tests were positive on IDT than on Multi-Test II (P < 0.001). The overall Spearman correlation coefficient between IDT endpoint and Multi-Test II score was 0.370 (P < 0.001).
CONCLUSION: Patients were more likely to have a positive test on IDT than on Multi-Test II. IDT therefore may be a more sensitive testing technique for inhalant allergies than Multi-Test II prick testing. In addition, Multi-Test II score may not be a good predictor of IDT endpoint. Although a statistically significant correlation is demonstrated between Multi-Test II score and IDT endpoint, the correlation coefficient is low enough that clinical application may not always be safe or appropriate. The clinical significance of positive IDT results in the presence of negative Multi-Test II results is not known
Table 1. Grading System for Skin Testing
Grade and Skin appearance
0: No reaction or reaction no different than
1: Erythema less than 21 mm
2: Wheal less than 3 mm and erythema larger
than 21 mm
3: Wheal greater than 3 mm with surrounding
4: Wheal with psuedopods and surrounding
SOURCE:McCann WA, Ownby DR. The reproducibility of the allergy skin test scoring and interpretation by board-certified/board eligible allergists. Ann Allergy Asthma Immunol. 2002;89:368–371
PATTERSON'S ALLERGIC DISEASES seventh edition
0.....no reaction or a reaction no different than negative control
1+.....erythema less than 21 mm and larger than negative control, no wheal
2+.... erythema laeger than 21 mm and larger than negative control, wheal less than 3mm
3+.....erythema and wheal formation of 3mm or greater and wheal formation without pseudopod
4+......erythema and wheal formation of 3mm or greater and wheal formation with pseudopod
Background: Previous comparisons of devices for percutaneous skin testing have revealed statistically and clinically significant differences, from one device to another, in the size of reactions to histamine and allergen extracts and at negative control sites.
Objective: The objective of this study was to compare the performance of several skin test devices which are either new, modified, or used with a modified technique.
Methods: Twenty subjects were tested five to eight times with each of the devices both to glycerol-saline and to 10 mg/ml histamine base. The devices tested were the MultiTest II, Duo Tip-Test (prick and scarification), Quintest, DermaPik (prick and scarification), and small pox needle.
Results: There were highly significant differences among the devices for the size of the reaction to histamine (mean wheal diameter 4.28 to 8.59 mm, p < 0.0001), the standard errors of the wheals to histamine (0.82 to 1.45 mm, p < 0.05) and in the mean wheal size with glycerol-saline (0.00 to 2.48 mm, p < 0.0001).
Conclusions: Devices for performing skin prick testing vary greatly in several characteristics, including the size of reactions at both positive and negative test sites. Each skin test technician should be tested with the device used in that skin testing laboratory to establish criteria for positive and negative tests. (J Allergy Clin Immunol 1998;101:153-6.)
A comparison of multiheaded devices for allergy skin testing
Harold S. Nelson, Catherine Kolehmainen, Jennie Lahr, James Murphy, Andrea Buchmeier
Journal of Allergy and Clinical Immunology Vol. 113, Issue 6, Pages 1218-1219, June 2004
Phil Lieberman, M.D.
Key Words: allergy skin tests, prick test, Multitest