Yup! Only about 20% of flu deaths are confirmed by test. The rest are estimated by an algorithm (which the OP alluded to) Sorry for AMP link, canonical url is

Yup! Only about 20% of flu deaths are confirmed by test. The rest are estimated by an algorithm (which the OP alluded to) Sorry for AMP link, canonical url is paywalled: https://www.google.com/amp/s/www.washingtonpost.com/business/2020/05/02/theres-more-accurate-way-compare-coronavirus-deaths-flu/%3foutputType=amp https://www.google.com/amp/s/www.washingtonpost.com/business... The CDC explains its methodology here. There are valid reasons to assume influenza deaths are higher than confirmed tested deaths. But many of these apply to coronavirus as well: https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm