A portion of an experiment to determine the limit of blank/limit of detection in a biochemical assay.

LoBD

Format

A data frame with 84 observations on the following 9 variables.

pool

a factor with levels 1 2 3 4 5 6 7 8 9 10 11 12 denoting the 12 pools used in the experiment; each pool had a different level of drug.

I1L1

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I1L2

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I2L1

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I2L2

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I3L1

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I3L2

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I4L1

a numeric vector giving the measured concentration in pmol/L of drug in the assay

I4L2

a numeric vector giving the measured concentration in pmol/L of drug in the assay

Details

Important characteristics of a clinical chemistry assay are its limit of blank (LoB), and its limit of detection (LoD). The LoB, conceptually the highest reading likely to be obtained from a zero-concentration sample, is defined operationally by the upper 95% point of readings obtained from samples that do not contain the analyte. The LoD, conceptually the lowest level of analyte that can be reliably determined not to be blank, is defined operationally as true value at which there is a 95% chance of the reading being above the LoB.

These data are from a portion of a LoB/D study of an assay for a drug used to treat certain cancers. Twelve pools were used, four of them blanks of different types, and eight with successively increasing drug levels. The 8 columns of the data set refer to measurements made using different instruments I and reagent lots L.

Source

Used as an illustrative application for Box-Cox type transformations with negative values in Hawkins and Weisberg (2015). For examples of its use, see bcnPower.

References

Hawkins, D. and Weisberg, S. (2015) Combining the Box-Cox Power and Generalized Log Transformations to Accommodate Negative Responses, submitted for publication.

Examples

LoBD
#>             pool I1L1 I1L2 I2L1 I2L2 I3L1 I3L2 I4L1 I4L2
#> 1  Blank_1_CAL_A    2    3    3   -8    3   -1    3    0
#> 2  Blank_1_CAL_A    0    1   -2   -6    1    2    1    4
#> 3  Blank_1_CAL_A   -1    1    3   -1   -1    3    5    3
#> 4  Blank_1_CAL_A   -1    2   -4    0    0    3    6    4
#> 5  Blank_1_CAL_A    0    1    2    0    0    1    2    1
#> 6  Blank_2_CAL_A   -4   -2    0    0    0   -2    1    4
#> 7  Blank_2_CAL_A    2    2   -1    1    2    0    2    1
#> 8  Blank_2_CAL_A    1    0    0   -2    3    0    6    4
#> 9  Blank_2_CAL_A   -2   -5   -1   -1    1    3    3    2
#> 10 Blank_2_CAL_A   -1    2   -1    0    1    1    8    2
#> 11  Blank_Plasma    2   -3   -1   -8    0    1    3    1
#> 12  Blank_Plasma    2    3   -2   -5    1    2    3    2
#> 13  Blank_Plasma   -5   -5   -1   -7   -1   -1    2    2
#> 14  Blank_Plasma   -4    2    3   -8   -1   -2    2    3
#> 15  Blank_Plasma   -1    5   -2    0   -1    2    4    6
#> 16   Blank_Serum   -1    1   -3   -5   -3   -3    1    0
#> 17   Blank_Serum    2   -4   -2   -8    1    0    3    3
#> 18   Blank_Serum   -2   -4   -4  -12    0    3    2   -1
#> 19   Blank_Serum    2   -1    3   -8   -1    1    2    4
#> 20   Blank_Serum    3    1   -2   -4    0    3    2    1
#> 21       Panel_1   11    9   10    9    9   11   13   10
#> 22       Panel_1   11   10    9    9    8   10   11    9
#> 23       Panel_1    9   10   10    8   10    8   11   10
#> 24       Panel_1    8   11    8    9    7   10   10    7
#> 25       Panel_1   11   12   10    9    8    7   12   12
#> 26       Panel_1   10   10    9    8    9    8   10   13
#> 27       Panel_1    9   11    7   10   10   11   11   10
#> 28       Panel_1    8   10   11    5    9    9   10    8
#> 29       Panel_2   20   18   17   17   18   19   22   20
#> 30       Panel_2   19   19   19   19   19   18   20   20
#> 31       Panel_2   17   19   19   21   18   18   22   18
#> 32       Panel_2   19   20   17   19   18   20   20   18
#> 33       Panel_2   18   19   20   20   18   18   19   21
#> 34       Panel_2   17   18   15   19   20   20   20   19
#> 35       Panel_2   21   20   18   20   17   19   20   20
#> 36       Panel_2   19   18   18   18   17   17   21   21
#> 37       Panel_3   31   27   29   30   29   27   32   30
#> 38       Panel_3   29   34   25   24   28   27   32   28
#> 39       Panel_3   29   28   28   31   28   29   30   25
#> 40       Panel_3   29   31   26   28   29   26   31   27
#> 41       Panel_3   27   27   28   29   28   29   29   27
#> 42       Panel_3   29   30   28   27   28   28   29   31
#> 43       Panel_3   29   29   29   30   26   27   31   28
#> 44       Panel_3   28   26   29   26   27   27   30   30
#> 45       Panel_4   38   37   40   36   38   37   39   37
#> 46       Panel_4   35   38   34   33   37   36   38   37
#> 47       Panel_4   39   38   37   35   34   36   39   34
#> 48       Panel_4   38   37   37   36   36   36   40   36
#> 49       Panel_4   36   36   38   34   38   37   39   36
#> 50       Panel_4   38   36   34   40   36   37   41   37
#> 51       Panel_4   39   35   37   39   39   36   39   39
#> 52       Panel_4   37   38   37   37   35   38   41   36
#> 53       Panel_5   52   51   47   46   45   47   49   43
#> 54       Panel_5   50   48   49   46   46   48   48   49
#> 55       Panel_5   46   45   47   49   47   46   52   45
#> 56       Panel_5   47   48   50   47   47   47   48   48
#> 57       Panel_5   49   49   50   46   48   46   50   46
#> 58       Panel_5   47   46   44   45   48   46   49   47
#> 59       Panel_5   50   45   47   47   48   47   49   46
#> 60       Panel_5   46   48   45   46   46   49   51   48
#> 61       Panel_6   80   78   74   80   77   78   80   79
#> 62       Panel_6   81   80   76   76   76   78   80   81
#> 63       Panel_6   79   74   81   71   76   78   80   75
#> 64       Panel_6   77   77   80   75   79   80   85   77
#> 65       Panel_6   77   73   75   78   77   77   84   79
#> 66       Panel_6   76   81   79   77   79   78   80   76
#> 67       Panel_6   80   74   83   82   81   75   84   79
#> 68       Panel_6   80   79   72   75   80   74   82   82
#> 69       Panel_7  108  100   94  106   99   97  101   96
#> 70       Panel_7  100   96   89   96   96   98   96  100
#> 71       Panel_7  106  103   95   99  100  100   98   95
#> 72       Panel_7   99  105  104   94  101  100  105  100
#> 73       Panel_7   99   97  108  107   98   95  100   98
#> 74       Panel_7  103   96   97   98   98   98  104   97
#> 75       Panel_7  110   95   93  101  100   98   96   98
#> 76       Panel_7  102   99   98   92   95   97  109  100
#> 77       Panel_8  205  192  212  189  194  199  210  191
#> 78       Panel_8  193  194  202  190  202  196  194  202
#> 79       Panel_8  201  196  191  186  195  192  207  202
#> 80       Panel_8  202  205  187  195  199  199  193  190
#> 81       Panel_8  207  204  207  198  197  203  195  193
#> 82       Panel_8  206  202  192  199  192  199  198  195
#> 83       Panel_8  207  190  192  197  192  200  200  200
#> 84       Panel_8  203  189  189  198  185  194  205  201