How could you take a nucleic acid test and an IgM antibody test and have it certified by an embassy 48 hours before traveling?

Question

China has introduced new rules for traveling.

The Chinese embassy in Belgium has updated their news to include a Notice on Airline Boarding Requirements for Certificates of Negative Nucleic Acid and Anti-Body Blood Tests Results.

Under Test Requirements it is noted that:

1. Passengers traveling to China via direct flights must, within 48 hours before boarding, conduct the sampling and testing of a nucleic acid test and a IgM anti-body test at qualified medical institutions in Belgium. After receiving the certificates for negative test results for both the nucleic acid and the anti-body test, passengers may present the test reports to the Embassy of China in Belgium to apply for a green health code with the "HS" mark or a certified health declaration form.

How could you take a nucleic acid test and an IgM antibody test 48 hours and have it certified by an embassy before traveling? 48 hours is surely not enough time to be able to complete all these tasks before an international flight.

The same criteria are also required of passengers catching connecting flights in a 3rd country. Belgium themselves have said that:

For passengers departing from a third country and traveling to China via Belgium, as the transit area at Brussels Airport is not yet equipped for conducting nuceic rapid tests and the anti-body tests for transit passengers, and passengers of Chinese nationality are not permitted for entering Belgium border unless in humanitarian circumstances, it is recommended that passengers bounding for China avoid transiting via Belgium.

Are these requirements even doable?

Answer 1

Are these requirements even doable?

Yes if your area has decent COVID-19 testing facilities.

As JonathanReez mentioned, PCR results can be obtained within the same day.

The same applies to anti-body tests, e.g. from https://www.fda.gov/consumers/consumer-updates/coronavirus-testing-basics:

E.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177139/:

The ALLTEST 2019-nCoV IgG/IgM Rapid Test Cassette is a rapid LFIA (turn-around time within 15 min) that uses a recombinant SARS-CoV-2 N protein to detect both IgM and IgG antibodies.

https://www.fda.gov/media/139792/download:

FYI: COVID-19 Testing FAQs from the American Society for Microbiology (mirror).

Answer 2

PCR tests take a few hours to process, so 48 hours is more than sufficient if there aren't bottlenecks in the test lab. For example, a Seattle company called Atlas Genomics advertises the following:

We provide travel testing with same day results. Please call xxx.xxx.xxxx
Atlas Covid-19 tests are being accepted by Hawaii due to our partnership with Discovery Health who is on the list of Trusted Partners.

Out of interest, I gave Atlas Genomics a call and they said they can do a same-day test Mon-Fri for $149, as long as you show up for the test before 12pm. So you could probably get tested on a Monday morning, email the Chinese consulate on Monday evening, get a confirmation Tuesday afternoon and fly out Wednesday morning - around 48 hours after taking your test.

You should be able to locate a similar lab with premium test processing in your area. Depending on the country/state, even free testing might be fast enough - my own free COVID test here in Seattle took less than 48 hours to process.