Stool for Shiga Toxin determination – Shipped November 06, 2017

ST1711-1: Negative      ST1711-2: Positive      ST1711-3: Positive     

Participant’s results



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.

Samples ST1711-2 and -3 consisted of E.coli O157:H7, shiga toxin positive. Sample ST1711-1 consisted of E.coli, non-O157:H7, shiga toxin negative.

Toxin detection was correctly performed by greater than 70 percent of all laboratories and was thus, determined to be suitable for grading.”

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 samples were tested Shiga toxin presence using the ‘ImmunoCard STAT!’ assay. The sample lot was confirmed to be homogeneous and stable for at least 17 days.

Grading of Shiga Toxin 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 critiques, Shiga Toxin Results