This blog is a follow on from the MOH diagnosis change taking effect from 21 May 2012 blog. Up until yesterday, the reports I'd concentrated on, were the ESR WEEKLY PERTUSSIS. After reading the diagnostic change blog, a vigilant reader gave a timely reminder that the reports needing reviewing, were the ESR MONTHLY REPORTS .
Solomon's mine, indeed. Starting from January 2011, the monthly reports reveal an interesting pattern.
The first mention of PCR use for diagnosis, comes in the November 2011 monthly report, where we are told that out of 494 total notifications, 108 (21.9%) were culture confirmed, and 82 (16.6%) were PCR confirmed.
December 2011 monthly report say that out of 540 notifications, 76 (14.1%) were culture confirmed and 105 (19.4%) were PCR confirmed.
January 2012 says that out of 430 notifications, 86 (20.0%) were culture confirmed, and ....14 (3.3%) were PCR, which is probably indicative of the fact that priorities are set by which sector of the medical profession "checks out" until 21 January. Diagnostics might have been pared back to bare essentials only.
February 2012 doesn't bother to tell us how many of the tests were either lab or PCR confirmed. Perhaps they still had holiday blues. Maybe they didn't bother to do either?
March 2012 tells us that out of 379 cases, 83 (21.9%) were culture confirmed and 141 (37.2%) were PCR confirmed.
April 2012 tell us that out of 328 cases, 48 (14.6%) were culture confirmed and 99 (30.2%) were PCR confirmed.
May 2012 tells us that out of the 572 cases, 48 (14.6%) were culture confirmed and 155 (27.1%) were PCR confirmed.
The PCR-boosted increase is seen in the graph which was published in the same 8th June weekly report which announced the diagnostic changes taking place FROM 31 May 2012.
By checking the numbers in all the monthly reports, with the numbers represented by the black line, the graph shows that the the PCR data has been included RETROSPECTIVELY:
Far from being a 31 May, 2012 directive, the ESR has already slid previous PCR confirmations into the official data, which means that the historical data is essentially meaningless. Not that it was anything but a crystal ball guestimate anyway.
PCR usage in March, April and May (MAM) 2012, averages out to around 31% excess of case notifications, had only the previous laboratory culture been used. As PCR diagnostic percentages increase, and culture rates decrease, it will be impossible to know just how much whooping cough is actually whooping cough, or contaminated PCR, or PCR false positives.
And given Fine 1984.....
The statistical experts are still defining the extent of any epidemic, by counting what little doesn't escape through the big black holes out into the "unknown".
So --- are 2011/2012 reported numbers coming from a crystal ball, or a collander?
