PRINCIPLES OF TOXICOLOGY

TABLE 12-3 NTP and Gene-Tox Evaluation of Short-Term Test Sensitivities and Specificities
Specificity b
Sensitivity a
Gene-Tox NTP
NTP d
Gene-Tox c
Assay (+)/Total %(+) (+)/Total %(+) (–)/Total %(–) (–)/Total %(–)
Ames/Salmonella 175/223 78 20/44 45 29/47 62 25/29 86
Mouse/lymphoma 45/54 87 31/44 70 0/5 0 13/29 45
CHO/HGPRT 40/41 98 — — 1/1 100 — —
V79 84/104 81 — — 3/3 100 — —
Drosophila SLRL 77/106 73 4/18 22 9/16 60 9/9 100
In vitro cytogenetics 40/54 74 24/44 55 2/6 33 20/29 69
In vivo cytogenetics 8/9 89 9/15 60 0/0 — 11/12 92
In vitro SCE 100/101 99 31/44 70 0/10 0 13/29 45
In vivo SCE 21/21 100 10/15 67 0/0 — 5/12 42
UDS in hepatocytes 19/22 86 6/30 20 0/0 — 13/14 93
Source: Kier (1988).
a
Sensitivity is the proportion of positive results for carcinogens.
b
Specificity is the proportion of negative results for noncarcinogens.
c
Gene-Tox data include combined results for sufficient and limited-evidence carcinogens and noncarcinogens.
d NTP specificity assumes that equivocal evidence compounds are noncarcinogens.
258