Stool: Clostridium difficile common antigen and toxin/toxin gene – Shipped November 07, 2016
CT163A: Positive/Positive CT163B: Negative/Negative
Reference Laboratories
CT163A: 12/12 laboratories reported C.difficile common antigen/gene/toxin positive/positive or not tested/positive
CT163B: 12/12 laboratories reported C.difficile common antigen/gene/toxin negative/negative, negative/not tested or not tested/negative
Participants’ results
Table 1. CT163-A - Antigen/Toxin or Toxin gene Total Grade
Positive / Positive 46 8/8
Not tested/Positive 9 4/4
Total 55
| Table 2. CT163A - IC /PH Notification | Total | Grade |
|---|---|---|
| Yes | 48 | 4/4 |
| No report | 6 | 0/4 |
| n/a (PH lab does not report directly to IC) | 1 | ungraded |
| Total | 55 |
| Table 3. CT163-B - Antigen/Toxin or Toxin gene | Total | Grade |
|---|---|---|
| Negative / Negative | 41 | 8/8 |
| Negative / Not tested | 5 | 4/4 |
| Not tested / Negative | 6 | 4/4 |
| Total | 55 |
PH: Public Health; IC: infection control
Suitability for Grading
A challenge is considered suitable for grading if agreement is reached by 80 percent of selected reference group and at least 70 percent of the participants.
Antigen and toxin detection was correctly performed by at least 80 percent of reference laboratories and greater than 70 percent of all laboratories thus, both challenges were determined to be suitable for grading.
Maximum grade: CT163A: 12 , CT163B: 8
The samples are assessed for homogeneity and stability using in-house quality control methods and random selection of samples before and during production, and post sample delivery. The number of random samples selected is based on selection tables within Military standard 105E (1).
The challenge sample lot was confirmed to be homogeneous and stable for at least 15 days.
Grading of Clostridium difficile common antigen and toxin/toxin gene detection is based on a Positive / Negative result, no further statistical analysis is performed on the results beyond that described under “Suitability for grading(1) Famum NR. Acceptance sampling. In: Modern Statistical Quality Control and Improvement. Belmont, California.: Duxbury Press; 1994:305.
