Serology Phase I QA.pdf

Serology Phase I Questions and Answers

1. In Section L6, Page 60 (now page 66 of track changes copy), you describe the proficiency panel.

You describe it thus: "The proficiency panel will contain samples and antigens to complete a panel of sera testing using the hemagglutination inhibition assay. “.

a. How many test samples are in this panel - 20

b. Will it contain any known control samples (i.e. either positive, or negative controls, or both) – controls will be included with the panel

c. The HAI assay generally uses a virus to induce agglutination. Is the “antigen” referred to in this proficiency w3panel a substitute for the virus, and we are to test against this antigen. In the next line, you describe the information we need to develop. Item 2 is "sample titers against the tested antigen(s)”, which would imply that we are substituting the provided antigen(s) for the virus. – antigen is a form of the test virus.

d. Assuming I have understood correctly, how many antigen(s) will be provided? Will the testing be done per antigen, or will the antigens be pooled together. – 3 antigens, each antigen needs to be tested individually.

e. Item 1 in the list of information required is the "virus back titration”. Does this refer to the antigen in the proficiency panel? Specifically, do you want us to determine the virus concentration in this antigen (e.g. via serial dilution and CPE)? Or, does this refer to the test samples itself, which may contain some live virus (not just antibodies), and we are to determine the virus concentration ? Your pass/fail criterion (down below) only lists seroconversion match rate, and % titers that are >2 fold different; so we found this to be a little confusing. – Back titration is the confirmation of antigen concentration as HAU.

2. In your pass/fail criterion, the first item is “seroconversion match rate” This will depend on the threshold used for defining positives. Will you define that? – 4-fold rise of the paired samples.

3. Do you need a YES/NO response, or do you also want a Viral Titer Level? – Page 60 of the solicitation states that the Offerors shall submit electronically the following information to the Contracting Officer: 1) virus back titration(s); and 2) sample titers against the tested antigen(s).

Further, page 60 also states that the sample titers must be submitted as single titer and geometric mean titers (per sample). Offerors may also submit additional information related to the sample testing as needed, including, but not limited to, sample hemadsorption to reduce any non-specific hemagglutinins, sample treatment, etc. Please report viral titer.

4. If you need a Viral Titer level, do you want it calibrated against a particular strain? – Yes If yes, then which strains? - CDC will specify the virus antigen. – CDC will specify the virus antigen.

5. How many samples do you want tested? – 20

6. Our lab uses Chicken, Turkey, Guinea Pig, and Horse RBCs depending on the specific virus we are using. Because we do not know what virus or antigen will be in the HAI proficiency panel, we have been ordering all four types of RBC so we are ready to go, no matter what virus is included. I am hoping to not buy all four types of RBC for a third time and was wondering if there is any way you can let us know what viruses will be in the proficiency panel. – The Lab’s suggestion is to have turkey red blood cells for the testing.