HONG KONG INSTITUTE OF MEDICAL LABORATORY SCIENCES

Quality Assurance Programme Limited

In collaboration with

Public Health Laboratory Services Branch

Centre for Health Protection

External Quality Assessment Programme

 in

Virus Serology

Survey materials

Inactivated simulated serum or plasma samples

- All the positive specimens in each survey are prepared from diluted reactive sera or plasma using normal plasma or Basematrix as the diluent, while the negative specimens are prepared using normal plasma or Basematrix.

- The samples are confirmed for their reactivity and aliquotted into final form before randomly selected for the homogeneity check. The result of homogeneity should show CV less than or equal to 20% for each of proficiency testing (PT) specimens. The statuses of the PT samples are further verified using various assays before being used in the PT exercise by sending them to a number of expert laboratories (number not less than 10% of the total participating laboratories).

- In each survey, PT specimens are selected among those that give at least 90% concordant results in the consensus study.

- The assigned result of each specimen is based on the overall results of the consensus study.

- Before being used as PT samples, a pre-distribution set and post-distribution set are tested and compared with the results obtained from homogeneity testing to ensure the stability of the samples during storage and during the period of delivery.

No.of survey materials

HIV Serology          - Five serum samples for anti-HIV testing

Hepatitis Serology   - Five serum samples for HBsAg and /or anti-HBs testing
                               - Five serum samples for anti- HCV testing

Frequency

Four times a year

Deadline for Return of Result

Two weeks after the dispatch of survey material

Quality Control of Survey Samples

Homogeneity Check

The samples are confirmed for their reactivity and aliquotted into final form before randomly selected for the homogeneity check. The result of homogeneity should show CV of less than or equal to 20% for each of proficiency testing specimens.

Stability Check

Respective set of proficiency testing specimens will be tested before and after distribution of each panel to ensure their stability during the period of shipment. Results of the pre-distribution set are also compared with the results obtained from homogeneity testing to ensure the stability of the samples during storage i.e. before being used as PT samples. Results of the pre-distribution set should be less than or equal to 20% as compared to the corresponding mean value of sample reading to cutoff value obtained from the homogeneity testing. Another respective set of PT samples is also tested after distribution to ensure their stability during the period of delivery. Results of the post-distribution set should be less than or equal to 20% as compared to the corresponding mean value of sample reading to cutoff value obtained from the homogeneity testing. The percentage difference of sample reading to cutoff value of each specimen between the pre- and post-distributions should be less than or equal to 20%. 

Test requested

Test all the specimens using the current assays in the laboratory for:

1.          HIV antibody,

2.          HBsAg; anti-HBs for HBsAg negative samples and

3.          Anti-HCV.

Request for replacement samples

Participants can request a replacement of survey materials by submitting a formal request. The request form can be downloaded at:

http://www.hkimlsqap.org/Information/Form/Specimen Replacement Form.pdf

Criteria for Performance Evaluation of Virus Serology

Timely Reporting

Participants are required to report the results before the due dates. Late returned results will not be scored.

Scoring of Result

Preliminary Result

Intended results will be posted online 3 weeks after the dispatch of survey materials.

Survey Reports

Final report will be issued quarterly to the participants documenting the identities of samples dispatched, intended results, reported results, scores achieved and assay methods used by respective participants. If there is a statistical difference in the performance for test methods used by each group of participants, this will be discussed. Late or nil return will be marked on the individual report of the participant. Year-end summaries of the total scores will be compiled and released.

Certificate of Participation

A certificate of participation will also be issued indicating the number of survey results returned timely.

Enquiry

Should there be any enquiry on the survey, participants are requested to contact HKIMLSQAP for assistance.

Appeal

Should there be any data discrepancy in the survey report or any disagreement with the performance evaluation; participant can appeal to the chairman of HKIMLSQAP for amendment and review.

Contact us:

(852) 2499 0015 [Phone]
(852) 2124 2798 [Fax]
info@hkimlsqap.org [Email]

The Chairman
Quality Assurance Programme Committee
Hong Kong Institute of Medical Laboratory Sciences Quality Assurance Programme Ltd.

Flat 1711, 17/F, Block C, Bell House,
525 - 543 Nathan Road, Yaumatei, Kowloon, Hong Kong.

Last updated on 17 September 2015.