FIELD W 

 Column 68 



(If "death" [of the individual or of a percentage of a population] is the response for which 

 the minimum dose needed has not been demonstrated [demonstrated by all of the two or 

 more dose levels tested having caused death to the individual or caused death to the same 

 percentage of a treated population], Symbol N is used in Field W, with some criterion other 

 than Criterion 2 or 21 in Field X. ) 



Three or more tests have been performed, each with a different dose level. (When the 

 response is "death", refer to the final statement in parentheses, below. ) 



Two or more of the doses tested produce the same intensity of response and one or more of 

 the doses tested produce a lower intensity of response. 



The maximum intensity of response of which the test compound is capable has been demon- 

 strated (the intensity on which the coded evaluation is based). 



The minimum dose needed to cause the maximum intensity of response has been demonstrated 

 (the coded dose). Do not use Symbol when Criterion 20 is used in Field X, unless "death" 

 (or other "all-or-none" response) is coded in Field T-2, as explained below. 



(If "death" [of the individual or of a percentage of a population] is the response for which 

 the minimum dose needed has been demonstrated [demonstrated by one of the doses admin- 

 istered not having caused death to the individual or not having caused any deaths when the 

 next larger dose (the threshold dose) causes 100% kill in a treated population]. Symbol 

 is used in Field W and Criterion 20 or 21 may be used in Field X. If maximum response is 

 100% kill and the minimum dose for causing 100% kill is demonstrated, yet the threshold 

 dose causes less than 100% kill, use of Criterion 20 or 21 demands a coded dose smaller 

 than the minimum dose needed to cause maximum response and Symbol can not be used in 

 Field W, but only Symbol P. ) 



P Two or more tests have been performed, each with a different dose level. (When the response 

 is "death", refer to the final statement in parentheses, below. ) 



All of the doses tested produce different response intensities (the larger the dose, the greater 

 the response intensity). 



The maximum response intensity of which the test compound is capable has not been demon- 

 strated; the intensity produced by the largest dose tested (the intensity on which code 

 evaluation Is based) may or may not be the maximum intensity which the test compound is 

 capable of producing. 



For each intensity produced in any of the tests, the dose producing it is the minimum needed 

 (i.e. , for the test being coded, a reasonable relationship exists between the dose coded 

 and the response intensity produced). When the threshold dose has been demonstrated and 

 Symbol 20 is used in Field X, Symbol P must be used in Field W except under special con- 

 ditions when "death" is coded in Field T-2, as explained in the final statements defining 

 the use of Symbol 0. 



(When "death" is coded in Field T-2 and administration is to a population and each dosage 

 level administered causes a different percentage kill, Symbol P is used in Field W and some 

 criterion other than Criterion 20 or 21 must be used in Field X. [See the final statements 

 below for the situation in which the threshold percentage kill by any dose administered to a 

 population is determined, when Symbol P is used with Criterion 20 or 21. ] "Death" to a 

 single treated individual or "death" to 100% of a treated population represent non-variable 

 response intensities [they must either occur as totalities or do not occur at all, at any dose] 

 and Symbol P can not be used to apply to them; use only Symbol N or [or Symbol M, if the 

 compound is tested at only one dose level, or Symbol J or K, if death did not occur]. Symbol 

 P is used when Criterion 20 is coded in Field X and the response for which the dosage coded 

 and shown by the test to be the threshold quantity is not death; Symbol P is used with Cri- 

 terion 20 or 21 when the response is "death" but only when application of the chemical has 

 been to a population, the threshold response is shown to be less than 100% kill , and in- 

 creasingly larger doses cause increasingly greater percentages of kill, meaning that the 

 coded dose is not the minimum causing the maximum response [for which Symbol is used], 



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