Estimate of False Negative Rates for the In Vivo Rabbit Dermal Corrosion Assay
R.R. Tice1,2, N.Y.
Choksi1,2, J. Haseman3, R.
Hill4, M. Lewis4, D. Lowther4,
W.S Stokes2
1. ILS, Inc., RTP, NC, USA. 2. NICEATM, NIEHS,
Research Triangle Park, NC, USA. 3. NIEHS, RTP, NC, USA.
4. EPA, Washington, DC, USA. 5. FDA, College Park, MD,
USA.
Alternative in vitro test methods proposed
to substitute or replace an in vivo assay should provide
equivalent or improved protection of human or animal health to
gain regulatory and general acceptance. ICCVAM evaluated four in
vitro dermal corrosivity assays as potential replacements for
the in vivo dermal corrosivity assay. ICCVAM recommended that
these assays be used in accordance with the globally harmonized
tiered testing scheme in a weight-of-evidence approach. In this
approach positive substances could be classified and labeled as
corrosives and negative substances are further evaluated in
accordance with an internationally accepted testing scheme. This
recommendation was based largely on the 12-17 percent false
negative rates of the in vitro assays in identifying corrosive
substances. ICCVAM concluded that these false negative rates
likely exceeded that of the currently used in vivo assay and
would not provide adequate public health protection. To estimate
the likelihood of a false negative result in the in vivo assay,
the available data was reviewed. Relevant in vivo dermal
corrosivity data were obtained from federal agencies and the
published literature. The database consisted of 50 corrosive
substances. Since the true likelihood of a corrosive response
for each of the substances in the database was unknown, the
sample rate was considered the best estimate of the true
positive response rate. Initial analysis of the database
indicated that the current in vivo dermal corrosivity test has
an estimated false negative rate of 5.5 percent. The analysis
also suggests that under-classification of a substance would
most likely occur only for weak corrosives. NICEATM continues to
seek additional high-quality in vivo corrosivity data to refine
the estimated in vivo assay false negative rate. This evaluation
emphasizes the need for high quality in vivo dermal corrosivity
data that can be used to evaluate the performance of proposed
alternative assays. ILS staff supported by NIEHS contract
N01-ES-35504.
This page was last updated May 9, 2007
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