CT2105

Stool: Clostridium difficile common antigen and toxin/toxin gene

CT2105A: Positive/Positive     CT2105B: Positive/Positive

CMPT QA/QC

CT2105-A: C.difficile common antigen positive and gene/toxin positive, viable for 60 days

CT2105-B: C.difficile common antigen positive and gene/toxin positive, viable for 60 days

Reference Laboratories

CT2105-A: 9/11 labs reported both antigen and toxin positive; one lab did not test antigen but reported toxin positive; one lab did not test antigen and reported toxin negative

CT2105-B: 9/11 labs reported both antigen and toxin positive; two labs did not test antigen but reported toxin positive

Participants’ results

NOTE: grading for Clostridium difficile toxin testing has changed. Please click here for more details

 

Table 1. CT2105A - Antigen/Toxin or Toxin geneTotalGrade
positive/positive48Acceptable/Acceptable
not tested/positive4Ungraded/Acceptable
not tested/negative1Ungraded/Unacceptable
not tested/not tested*2Ungraded/Ungraded
No report/No report1Unacceptable/Unacceptable
Total56

*Labs could not process samples because of specific incidents.

Table 2. CT2105A - IC /PH NotificationTotalGrade
YES50Acceptable
NO (reported positive)1Unacceptable
NO (reported positive)**1Ungraded
Not applicable (reported negative, no reported)4Ungraded
Total56

**PH authority does not require this lab to report to infection control for outpatients

 

Table 1. CT2105B - Antigen/Toxin or Toxin geneTotalGrade
positive/positive48Acceptable/Acceptable
not tested/positive5Ungraded/Acceptable
not tested/not tested*2Ungraded/Ungraded
no report/no report1Unacceptable/Unacceptable
Total56

*Labs could not process samples because of specific incidents.

Table 2. CT2105B - IC /PH NotificationTotalGrade
YES51Acceptable
NO (reported positive)1Unacceptable
NO (reported positive)**1Ungraded
Not applicable (not tested/no report)3Ungraded
Total56

**PH authority does not require this lab to report to infection control for outpatients

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.

Grading: Please note that grading for Clostridium difficile toxin testing has changed. Please click here for more details

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 60 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.

Posted in CDNews, Clostridium difficile Results, critiques