Current data quality grade
To help the public understand how well each state is performing, we have assigned each state a data-quality grade based on our assessment of the completeness of their reporting. Learn more
Between March 31 and April 15, 2020, Washington state did not report Negative PCR tests (people).
On April 18, 2020, Washington state removed 190 confirmed cases that were discovered to be out-of-state residents tested in Washington laboratories.
On June 18, 2020, Washington revised its Total PCR tests (people) downward. On the same date, Washington decreased its count of COVID-19 deaths by 7, because it determined that even though those 7 people had tested positive for COVID-19, COVID-19 was not a contributing cause in their deaths.
On June 22, 2020, we updated previous values for cases and total tests in our time-series using data from Washington state's dashboard. This update caused an artificial decrease in cases and tests between June 21 and June 22.
On July 14, 2020, Washington state revised its count of COVID-19 deaths downward by 39, because it determined that even though those 39 people had tested positive for COVID-19, COVID-19 was not a contributing cause in their deaths.
On August 2, 2020, Washington state Department of Health reported that "DOH is continuing to experience issues with its reporting system today. We are able to report cases, deaths and hospitalizations but have not reported new negative test results since 8/1."
On August 26, 2020, Washington switched its total tests units to testing encounters, excluding future encounters from individuals who test positive. It also provided a full timeseries of the figure. This testing encounters figure is slightly different from how we define testing encounters in two ways: first, our definition of testing encounters includes encounters after a positive test, and second, it should be calculated not by summing resulted tests but by counting all daily tests in a separate reporting stream. Despite these differences, the historical and current values of Washington’s figure are still stored in our Total PCR tests (test encounters) field.
As of September 18, 2020, Washington's total test results are drawn from our
totalTestEncountersViral field instead of calculated via positive+negative.
Washington State reports confirmed cases, laboratory tests, and deaths as of the previous day.
We report the most recent hospitalization data available for Washington. In some cases, this data may be reviewed and revised by the Washington State Department of Health. As a result, Washington considers hospitalization data complete after a 18-day lag period. In our data this lag is 20 days.
New tests (Calculated)Total PCR tests (test encounters)
New cases (Calculated)
New deaths (Calculated)
We calculate daily changes based on the data states report each day. Some states report new cases, tests, and deaths using other methods. Please consult official state data sources for more information. We chart “New tests” using different units across jurisdictions, because not all states and territories report tests in the same units. Learn more about total test units and see what we chart for each jurisdiction in our total tests documentation.
We do not have a complete dataset for every metric in every state. If we we have data for less than 30% of the past 90 days for a given metric, you’ll see a warning instead of a chart for that metric.
All the data for these charts is available for download. You can also review tabular national data on our US historical data page and data for each state and territory on the individual state or territory’s overview page.
Viral (PCR) testsHistorical data for viral (PCR) tests
(in test encounters)