Hadassah and the Hebrew University performed 130,000 corona tests while saving 76% of the test systems
A group of researchers led by Dr. Moran Yassour and Prof. Dana Wolf presents first-of-its-kind findings about the sensitivity and effectiveness of the pooling method, which allows testing up to eight subjects with a single test. Newspaper nature He praised the results of the study in the periodic Corona update he published for the month of November
In the months of April-September she performed The Virology Department of Hadassah Hospital with the assistance of the Hebrew University of Jerusalem About 130,000 corona tests (Covid-19) Using the method of pooling test tubes (pooling). This method, applied in pioneering in Israel by the joint team of Hadassah and the university, designed to perform high-throughput screening tests while significantly saving on test kits. The method was highly praised by researchers from Israel and the world, and even led according to The latest publications in the media For a real change in morbidity in Uruguay - which, unlike its neighbors, preceded to carry out pooling tests and as a result, during the three months of the first wave, no more than five cases per person were transferred, and in most cases the chain was broken after no more than two patients. This country also became one of the first countries to open schools safely.
Widespread detection of asymptomatic
Widespread use of pooling is intended for monitoring outbreaks of the virus, and constant scanning of populations at high risk of contracting the virus or developing severe symptoms. From the analysis of the test data recently carried out as part of a study by the researchers Prof. Dana Wolf from Hadassah Hospital, Dr. Moran Yassur and student Neta Barak from the Faculty of Medicine and the School of Engineering and Computer Science, it appears that the tests of 133,816 asymptomatic subjects were tested using only 32,466 test kits - saving about 76% of the tests.
The pooling idea described in the new study is fundamentally simple, and was first proposed by statistician Robert Dorfman in 1943 for comprehensive tests of soldiers for syphilis. Samples from several subjects are put into one test tube (pool), which is tested using a PCR test, which is the currently accepted corona test. If the pool received a negative answer, a negative answer is reported for all the tests that make it up. If the pool received a positive answer, all the individual tests that make it up are tested individually and the results are transferred separately for each test.
The decision to perform pooling tests in corona patients was based largely on theoretical and empirical studies in smaller samples (as well as a previous article by Hadassah and the Hebrew University), which offered a significant improvement in efficiency while maintaining a significant percentage of the test's sensitivity. Also, the pooling process is already being used in tests to detect various diseases in blood banks.
The efficiency (that is, the percentage of tests that can be saved) of pooling the tests depends on two key factors - the percentage of positives in the population and the size of the 'pool'. In general, the lower the percentage of positives in the population, the larger the size of the 'pool' that will provide maximum efficiency. Throughout the period there were significant fluctuations in the percentage of positives among the survey population - between 0.5% and 6%. In order to maintain the maximum effectiveness of the tests were carried out using 5 or 8 sample size pods, according to the current percentage of positives. In addition to the improvement in efficiency, a minimal impairment in sensitivity was observed, which supports the claims according to which the pooling of corona tests is safe to use.
The new study on the method has been submitted for peer review in a scientific journal, and is now appearing on the medRxiv pre-publication articles server, and was mentioned about two weeks ago In the weekly nature update, which reviews developments in the Corona research. "This experiment, on a large scale, showed that pooling tests can be extremely effective, even beyond theoretical predictions," Written in the mention of the prestigious journal. "The researchers used only about a quarter of all the tests they needed to test all the samples individually." Student Neta Barak summarizes: "The scale of the study, which includes a total of 133,816 tests tested using 17,945 poles, is the first of its kind, and allows for a better than ever assessment of the effect of pooling tests on the sensitivity and efficiency of the tests."
More of the topic in Hayadan:
An accurate method for diagnosing corona without the need for PCR amplification
Highly effective coronavirus antibodies identified will form the basis of a passive COVID-19 vaccine
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This is certainly great and welcome, but it is not clear why a positive result of the test requires an individual test of all the samples in it. Is it not possible to split the 8 test tubes into 4 and 4? Thus, instead of 8 tests, 5 or 6 are performed.
What, saving 20-30% is not saving?
Besides, I wonder what the theory says about adding each test tube from a positive pool to its own separate pool with 7 other samples. It is interesting to run a probabilistic model with 1-6% positive cells randomly scattered and normally distributed
Simply amazing. Common sense.
simply incredible