There is good news in testing. As Mr. Trump has said, the US is doing a large amount of testing. Of the major countries in the world, the US has done more testing than any of them save China. China has performed over 90 million tests, the US over 55 million, Russia over 27 million and India over 17 million.
When adjusted for population (tests per million), the US is still very high compared to major countries, being eclipsed solely by Russia and the UK.
The UK has performed 224 thousand tests per million, Russia has performed 189 thousand, the US has performed 169 thousand, Italy has performed 110 thousand and Germany has performed 89 thousand.
(you knew there was going to be “but” here, didn’t you?)
Here are some very important pieces of information to keep in mind when looking at these statistics.
- TESTS ARE SNAPSHOTS
Tests are only a snapshot of any one individual at the time of the test. Community tests are also only snapshots of that community at the time of the test. There is no “cumulative” value to the number of tests done. In other words, if you are tested today and found to be negative, it does not mean that you will not be found to be positive if you are tested again next week, next month or next year. The fact that 20% of a population has been tested over the past 6 months has little long-term value, as it does not mean that you needn’t test those people again.
Therefore, the large number of tests that were done last month are effectively valueless today. - THE NUMBER OF TESTS DOES NOT EQUAL THE NUMBER OF PEOPLE TESTED
The gross number of tests performed is not equal to the number of people tested. We have discussed this in the past, but it is worth recapitulating that people are often tested multiple times before they are allowed to leave a hospital, visit the President or play in a sports league. Having tested negative at one point in time does not mean that you will not need to be tested again after having been exposed to a person who has tested positive at a later date. - TESTING IS STILL VERY RESTRICTED
If you or someone you know has wanted to be tested recently you may very well have seen that navigating the system to get that test is not open water. You must “qualify” for the test; you must meet certain gated thresholds of symptoms or situations in order to be allowed to get a test, and it is even more difficult to get follow-on testing to give you assurances that the first test was accurate or that the first test was not too early on in the disease to have been able to be positive. With these restrictions in place, testing is still skewed towards the more likely diseased populations. - TESTING NUMBERS REFLECT PUBLIC ANXIETY
Most testing is currently initiated at the request of an individual. Although a fraction of tests performed are used for contact tracing, or for family members of patients hospitalized, the vast majority of test requests come from people who want to know if they have been infected based on their own perception of risk. That is why the lines at testing centers are so long. Individuals, depending on their zip code may be able to simply show up, or they may be required to fill out a request online to determine their eligibility for a test, or they may be required to contact their physician to get a testing order. Nevertheless, in all of those instances the initiation of the process begins with the individual.
The result of this individual-initiated testing is that if you increase or decrease the attendant risk-awareness that an individual calculates, you will simultaneously increase or decrease the demand for testing. For example, if you are currently living in Italy which has a current daily new case rate of around 350, your concern that you might be infected would most likely be quite low and your urgency to get tested may likewise be low.
On the other hand, if you were in the US where yesterday there were almost 70,000 new cases, your concern might be quite high and your urgency to get tested likewise high. The net effect of this social pressure is higher testing rates in countries with higher daily case rates.
In some countries testing demand outstrips testing availability as in the USA. In others testing demand is lower than availability and testing resources are used by health services for contact tracing and statistical analysis.
The observation here is that the demand for testing which impels the testing rates is fed by increasing case rates, hospitalization rates and death rates.
- We will NEVER reach a level of testing that is sufficient. This is simply an absolute. Since testing is only determinative for the day of the test, and only valuable if the data is analyzed and returned to the individual with 24 hours, and since the value expires within a matter of days after the results are analyzed, the only truly successful testing regime would test a majority of individuals every 4-5 days to be able to track susceptibility and spread. This cannot be achieved. Therefore, the value of testing needs to be viewed as a tool for contact tracing and exposure risk, not as some metric of national pride.