ColloquiumSCINSCAN PAAMOST
dr. N.W. de Jong
Erasmus MC
Rotterdam
Topics
Factors influencing skin test
Literature
Erasmus MC
Demonstration
Cut-off value
Distribution
Factors influencing skin prick test result
Allergen:
quantitypotencyquality
Design of lancet:
Needle hight needle thicknessShape of shoulder
Drawing of the wheal:
PerformancePen thicknessInk diffusion in skin and adhesive tape
Performance:
PressureAngleTime
Histological features:
Density of mast cellsIgE on mast cellsThickness of skinDensity of receptors
Area determination:
Plus signs (1+ - 5+)Mean diameter L + W /2Area calculation:
π x (D mean/2) 2
L.K. Poulsen, C. Bindslev- Jensen, H.J. Malling Clun. Exp. Allergy 1993,23;61-8
Scanning skin test results
Advantages
Reproducibility ?
Accuracy ?
Efficiency?
Digital ?
Cut-off values?
Statistical analysis?
Elips Polygonal
Wohrl S, Vigl K, Binder M, Stingl G, Prinz M. Exp Dermatol. 2006 Feb;15(2):119-24
1.Poulsen LK, Lijsberg C, Binslev-Jensen C, Mailing HJ. Precise area determination of skin prick tests: validation of a scanning device and software for a personal computer. Clin Exp Allergy 1993;23:61-8.
2.Poulsen LK, Binslev- Jensen C, Rihoux JP. Quantitative determination of skin reactivity by two semiautomatic devices for skin prick test area measurements. Agents Actions. 1994 Jun;41 Spec No:C134-5.
3.Pijnenborg H, Nilsson L, Dreborg S. Estimation of skin prick tests reactions with a scanning program. Allergy 1996:51:782-8.
4.Eigenmann PA, Sampson HA. Interpreting skin prick tests in the evaluation of food allergy in children. Pediatr Allergy Immunol. 1998 Nov;9(4):186-91.
5.Wohrl S, Vigl K, Binder M, Stingl G, Prinz M. Automated measurement of skin prick tests: an advance towards exact calculation of wheal size. Exp Dermatol. 2006 Feb;15(2):119-24
Literaturescanning method
1.Poulsen LK, Lijsberg C, Binslev-Jensen C, Mailing HJ. Precise area determination of skin prick tests: validation of a scanning device and software for a personal computer. Clin Exp Allergy 1993;23:61-8.
-Cutting and weighting paper
-Area by diameters
-Hand held scanner
Conclusion: hand held scanner highly precise, easy to use, time consuming (5 min/ skin test)
Literature
2.Poulsen LK, Binslev- Jensen C, Rihoux JP. Quantitative
determination of skin reactivity by two semiautomatic devices
for skin prick test area measurements. Agents Actions. 1994
Jun;41 Spec No:C134-5.
comparing 2080 spt’s
-digitizer pen
-hand held scanner
Conclusion: digitizer gives larger areas than the scanner, scanner more
precise
Literature
3.Pijnenborg H, Nilsson L, Dreborg S. Estimation of skin prick
tests reactions with a scanning program. Allergy1996:51:782-8.
Comparing 160 SPT’s:
-Area = π x (D mean/2) 2
-Scanning method:
encircled, transferred to a record sheet by means of translucent tape
Conclusion: Area scanner significant more precise, better CV
Literature
4. Eigenmann PA, Sampson HA. Interpreting skin prick tests in
the evaluation of food allergy in children. Pediatr Allergy
Immunol. 1998 Nov;9(4):186-91.
Comparing two SPT’s recording methods with oral food challenge (n=160)
-mean wheal diameter
-hand held scanner
sensitivity/ specificity
Conclusion: no significant differences in predictive values between methods
Literature
5.Wohrl S, Vigl K, Binder M, Stingl G, Prinz M. Automated
measurement of skin prick tests: an advance towards exact
calculation of wheal size. Exp Dermatol. 2006 Feb;15(2):119-24
Software automatically analysis scanned images and calculates the size of
wheals inner border.
Pilot study:
Comparing 110 SPT’s Histamine. CV area versus Diameter
CV horizontal diameter: 37.9%
CV maximal/ minimal diameter: 25.9%
CV scanning method: 11.9%
Literature
Scanning method
Wohrl S, Vigl K, Binder M, Stingl G, Prinz M. Exp Dermatol. 2006 Feb;15(2):119-24
a. Original imageb. Blue color to greyc. Increase contrastd. Wheal’s contour
middle e. Close gapsf- i superimposition of reconstruction
NW de Jong*, E Hoorn**, PGH Mulder***,H de Groot*, R Gerth van Wijk**Department of Allergology, **Department of Information and Technology, ***Department of Epidemiology & Biostatistics, Erasmus MC, Rotterdam, the Netherlands
SKINSCAN development 1998- …
-Poster 2002: Determination of ICT and SPT reactions with a scanning program
-Analyse 2005: Calculating Heic and Hep index with a scanning program.
-Thesis N.W. de Jong 2004: Reproducibility and stability of "in house manufactured" extracts used in the diagnosis of IgE mediated allergy.
NW de Jong*, E Hoorn**, PGH Mulder***,H de Groot*, R Gerth van Wijk*
*Department of Allergology, **Department of Information and Technology, ***Department of Epidemiology & Biostatistics, Erasmus MC, Rotterdam, the Netherlands
Results:Reproducibility SPT; histamine response 8 replicate observations per subject.
Intraoperator c.v 0.82%, Interoperator c.v.: 0.95%, day-to-day c.v. : 1.53%
Comparing with Pijnenborg et al.:Intraoperator c.v.: 1.4%, Interoperator: 2.3%, day -to- day c.v.: 1.9%
Skinscan
Demonstration
Suppression of histamine and grass pollen induced early and late phase skin reaction by levocetirizine (LCTZ). (In press)Dr. N.W de Jong*, E. Hoorn**, Dr. PGH Mulder***, Prof. Dr. R. Gerth van Wijk*
N = 240
Histamine
CV SPT 19% (Niemeyer 27.2%)
(Lower SPT areas may lead to
big measurement errors when
calculated by hand.)
CV ICT 15% (Niemeyer 15.9 %)
Grass pollen
CV SPT 20%
CV ICT 13%
CV late phase skin 26%. (N =
120)
The use of the skinscan program to calculate skin test areas in scientific research. Coefficient of variation
Chapter 7: Optimization of Skin testing, evaluation of cut-off values
Optimally cut-off value using mean wheal diameter: ICT 0.7, SPT 0.4
Predictive value:
ICT: RAST 83%; Anamnesis 77%
SPT: RAST 77%; Anamnesis 86%
Examples: ICT
Histamine 8 mm; grass pollen 5 mm:5/8 = 0.62 (negative) or 6/8 = 0.75 (positive)
SPT
Histamine 7 mm; peanut 3 mm: 3/7 = 0.42 (positive)
Skin test reagent in the diagnosis of atopic diseaseN.R. Niemeyer; thesis 1996
n = 1500
6 differentinhalationallergens:
D. pteronyssiusBirchGrassMugwortKatDog
Determination of cut-off values using skin test areaHEIC index: Histamine Equivalent Intracutanous index Area versus diameter
HEIC Cut off value X (diameter) = 0.7; Y (AREA) = 0.55
HEP Cut off value X (diameter) = 0.4; Y = (AREA) = 0.21
Determination of cut-off values using skin test areaHEP index: Histamine Equivalent Prick indexArea versus diameter
n = 1200
10 different
Food allergens: Scrimp
Curry
Egg- white
Cows milk
Peanut
Soy
Peach
Wheat
Celery
Tomato
totalen hep diameter < 2.0
y = 0,6362x2 + 0,2738x
R2 = 0,9506
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
4,00
0,00 0,50 1,00 1,50 2,00 2,50
hep diameter
hep
are
a
Skinscan
Advantages
Reproducibility: low CV intra, inter & day to day
Accuracy: low CV SPT & ICT
Efficiency: fast, easy, cheap
Digital: step forward to electronic dossier
Cut-off values more research on predictive values
Statistical analysis via access, statistics are easily done
Future: Dutch data bank skin test results
St. Elisabeth ziekenhuis, Tilburg
Leids Universitair Medisch, Centrum
Universitair Centrum, Maastricht
Universitair Medisch Centrum, Groningen
Maasstad, Rotterdam
Diakonessenhuis, Utrecht
Diakonessenhuis, Voorburg
Scinscan distribution
ColloquiumSkinScan PAAMOST
Dept. of Information and Technology:
Ed Hoorn
Nico Drost
Dept of Epidemiology & Biostatistics:
Paul Mulder
Dept. of Allergology:
Nicolette de Jong
Ilse Groenendijk
Hans de Groot
Roy Gerth van Wijk