[Application of multiple limits regression in dealing with nondetects with multiple limits of detect].
OBJECTIVE
To investigate the application of Multiple Limit Regression (MR), that is alternative to regression on order statistics, in imputing nondetacts below multiple detect limits.


METHODS
The Multiple limits regression method was used to dealing with the nondetects in cadmium residue in Fish food in 2004 from China markets; The nondetects are imputed with the predicted values based on MR; The results of estimates are compared with those from simple substitution methods. The analysis was performed using self compiled SAS macro code.


RESULTS
The mean estimated by MR methods is 0.01509 mg/kg, the means from substitution methods with 0, 1/2LOD and LOD are 0.014759, 0.015270, 0.015781 respectively.


CONCLUSIONS
MR is a worthy recommendatory method in handling nondetects with multiple limits of detect for its rationality and can be completed conveniently by compiled SAS macro code.
Yu
Xiaojin
X
School of Public Health, Southeast University, Nanjing 210009, China. xiaojin71@sohu.com
Liu
Pei
P
Min
Jie
J
Zhang
Hong
H
D000818:Animals; D015982:Bias; D002104:Cadmium / Q000032:analysis*; D003627:Data Interpretation, Statistical; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005399:Fishes; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D008962:Models, Theoretical; D012044:Regression Analysis
D002104:Cadmium