Experience Of Molecular Pathology Laboratories Confirming Cases Of Swine Influenza A Described

Dr. Jan Nowak, President of the Association for Molecular Pathology presented public comments September 10 at the Clinical Laboratory Improvement Advisory Committee meeting. During the initial weeks of the pandemic H1N1 influenza outbreak, community based molecular pathology laboratories developed diagnostic tests capable of rapidly detecting and confirming suspected cases of pandemic flu. Dr. Nowak reported on the efforts to confirm suspected cases in the Chicago area and among the broader AMP membership and discussed the challenges encountered by the diagnostic community as well as the opportunities to improve access to high quality rapid diagnostic tests for pandemic influenza.

AMP members stand ready to help with surge capacity during a reemergence of pandemic influenza strain during this year's flu season. Last April, when the first reports of the novel H1N1 influenza strain began to appear, community molecular pathology laboratories were confronted with the task of providing timely, useful information to their clinicians about this new infectious agent. An informal survey of AMP member laboratories during the first week of the H1N1 episode showed that 93% of the 43 respondents had a molecular assay that could detect and distinguish Influenza Type A from Type B. Those laboratories had an aggregate test capacity of 3,000 to 4,000 specimens/day, and could expand their capacity to as much as 12,000 specimens/day within 30 days if needed. Thirty-six percent of the laboratories reported having the capability of distinguishing the novel H1N1 strain from seasonal H1 strains. During week one of the outbreak, those laboratories had an aggregate test capacity approaching 2,500 specimens/day, with a potential of nearly 8,000 specimens/day within 30 days.

AMP members are uniquely qualified to develop and validate rapid diagnostics to confirm clinical cases of pandemic flu.

Early in week one of the outbreak, the molecular laboratories in the Chicago area participated in a conference call with the Illinois Department of Public Health to exchange information about tests in use, testing capacity, confirmatory capabilities, etc. Within a week the community labs had sufficient information to know that available assays for influenza A were capable of detecting the novel H1N1 strain, and furthermore, that some assays were capable of specifically identifying the novel H1N1 subtype. This knowledge greatly reduced the number of specimens that needed to be confirmed by IDPH. By the end of week two of the outbreak, many labs had sufficient data from IDPH to validate their assays, and were asked to limit their submissions for IDPH confirmation. After four weeks, more cases of H1N1 had been diagnosed in community molecular diagnostic laboratories (790 cases) than by IDPH (698 cases).

Dr. Nowak shared his experience, "by the end of the first week of the H1N1 episode, our own laboratory had identified 39 cases of probable H1N1 infection, only a fraction of which had been corroborated by our state public health laboratory, and confirmed only sometime after day 8." The CDC tally for all of Illinois at the end that week was still only 3 cases confirmed, a number widely reported in the media, which greatly misinformed the public and the medical community of the true nature of the spread of this disease in Illinois.

With the President's Council of Advisors on Science and Technology warning that more than half of the US population will be infected with the H1N1 influenza virus this flu season, AMP encourages close collaboration between molecular diagnostics laboratories, CDC, and public health laboratories to ensure prompt diagnosis and timely surveillance of the outbreak. Dr. Nowak expressed his pride in his profession's role in the outbreak, "In the recent H1N1 outbreak, I believe the quality of laboratory testing has been outstanding, as has been the response of molecular diagnostics laboratories to this public health emergency."