Covid-19: The blood tests we need to break the pandemic have finally started
Stanford and the state of California are doing something very right.
Some 2,500 blood samples for Covid antibody testing were taken Friday and Saturday in Santa Clara County at three Stanford University–run testing sites.
This is the first large-scale study of its kind in the U.S. — and, as I have argued at (too great) length here — is the the type of test necessary to eventually break the pandemic and restart the economy.
Volunteers signed up for test slots online; these were gone within hours. On Friday and Saturday, in Mountain View, San Jose and Los Gatos , they drove through pinprick blood collection stations set up in tents in church parking lots. Motorists rolled down their car windows and put out their hand.
Because blood samples do not contain live virus, the protective gear needed by the medical students, nurses, other volunteers taking the finger-stick samples were only lab-standard masks, gloves and gowns — not the hazmat suits seen on TV.
The pinprick itself, needed to squeeze a small sample of blood into a vial, took only a second and “didn’t hurt,” according to a 12-year old.
With paperwork, the cars moved through each parallel testing lane every 5 minutes. The actual testing of the blood samples will take place over the weekend at a Stanford lab, using a SARS-CoVid-2 antibody test of it own design.
(An FDA emergency-use authorization of the Stanford-devised antibody test is necessary formality, but on Saturday afternoon (April 4, 2020), California Gov. Gavin Newsom told reporters that FDA approval for the test was “hours away.”)
The chemistry of the test itself is very fast, approximately 15 minutes. First results are expected by Sunday evening. Anyone whose blood test returns positive will be notified .
However, the blood antibody test is not designed for —nor is it intended to be — -a replacement for the backlogged PCR tests that are the gold standard for clinical diagnosis. Those test for live virus in the nose and throat.
The blood tests looks for two infection-produced immunoglobulins, IgM and IgG. There is a 4-square grid of result outcomes. I explain the “fuzzy logic” of the antibody and PCR test results here.
To simplify, if the blood test returns full-on positive (IgM AND IgG), the test subject could be an asymptomatic carrier .
If the test result is positive on IgG only, the implication is that the test subject had a SARS-CoVid-2 infection sometime in the past, but is over it — and may well be immune.
The release signed by the test volunteers shares the results the Santa Clara County Department of Health, which coordinated the program.
Just last Friday (April 3, 2020), the state had an embarrassing backlog of 60,000 PCR tests stuck in processing, a number Gov. Newsom said on late Saturday afternoon had been reduced to 13,000.
The Stanford researchers plan to collect a similar number of blood samples in the Los Angeles soon.
The small Colorado ski town of Telluride plans offer a free blood antibody test to all 8,000 of its residents of those of the surrounding county. The testing will be sponsored in part by the co-founders of pharmaceutical company c19, who live there.
On Tuesday (March 31, 2020), researchers at the University of Bonn started a blood antibody ssurvey of 1,000 people in the western German region of Heinsberg, the site of one of Germany’s largest outbreaks. Many residents were apparently infected at a local carnival celebration in late February.
The 1,000 have been chosen as representative of the German population as a whole.
A number of epidemiologists have called for the U.S. to test a random sample of its general population to get a handle on the level of infection in rural and non-hotspot areas.
The World Health Organization (WHO) a few days ago launched a program to study blood samples from a half-dozen countries.
At least a dozen private companies around the world are in a race to get out inexpensive, single-use versions of the blood antibody test
These resemble home pregnancy tests.
While not initially intended for use by consumers at home, if the these blood-drop test work well enough, they offer immediate promise for health care workers who are presumably capable of self-administering them.
Oxford University is currently evaluating some nine different models. The UK has announced its willingness to buy millions of the kits, initially to provide to workers at the NHS.