What does Ecuador require to be shown on a COVID-19 PCR test in order to enter the country?

Sorry I have no hard data on Ecuador but can share some recent experience from Germany.

• There do not appear to be some well defined rules and there is some room for interpretation.
• There is no standard format for test results and the people checking them are struggling to make sense of various screen shots or print outs. Everybody is improvising a bit.
• I submitted the same test format twice. One was accepted, the other one didn't. They difference? 2 miles. Turns out the hotel I was staying, was in a different town and a different local health offices applied different standards.

Some suggestions:

• The requirements all reference the date the sample was taken (not the result date). If that's not included in the report, that's probably a non-starter. Reports that show both sample date and time are preferred.
• Double up. Get tested at least twice by different labs and bring both reports. If you have trouble with one, chances are they are going to accept the other.
• Something official looking with a lab logo, lots of medical mumbo jumbo and a signature on it will look better.
• Find out which entity needs to see the report and try to contact them up front. Send them an example and ask if that's ok. In your case you need to figure out who is in charge for granting quarantine exemptions. This may be a entirely different entity than the one that determines admission to the country or your eligibility to board the plane. Do NOT assume that each entity will use the same standards. What's acceptable to immigration may not be acceptable to the health board.

I am scheduled to fly to Ecuador (Guayaquil) in a few months from the US. Ecuador currently requires a negative COVID-19 PCR test from no more than 10 days before entry in order to avoid quarantine. I found this and other useful information on the US Embassy site. I also found similar information in Spanish from what appears to be the official Ecuadorian embassy site (plus Galápagos-specific information in English).

Yes, indeed. Moreover, they run random tests, and if you get a POSITIVE even with a negative PCR result you need to go to quarantine (called APO: aislamiento preventive obligatorio) in a place designated by the government, as explained in the last information release from the National Emergency Operation Committee (COE Nacional). Also, you need to fill the Traveler Health Declaration form, one per family. And finally, if you have symptoms, independently of the negative PCR result, you get an antigen test, and if positive, you pass under the care of the Ecuadorian health system and need to follow their orders (quarantine for sure, and medical care).

However, I cannot find any information about what specifically counts as a negative COVID-19 PCR test. I get regular COVID-19 tests via test-at-home kits, and each test result shows (in English):

• My name
• The approving physician's name The type of the test (SARS-CoV-2 RT-PCR)
• A test ID/locator number The "result date" (just the date, no time). This is not actually the date the test sample was collected from me, just the date the lab finished analyzing it (typically a couple days later).
• The result: "Not Detected" for a negative test
• The name/logo of the lab that performed the test

Is a printout of such a test result enough to qualify for entry to Ecuador, or do I need a test result showing more information? Would it be better to directly show the website containing the test result on my phone? Where could I find authoritative information on this topic?

Regarding this, it is true that is not easy to get information on what exactly is required to be written in the PCR result. I would recommend you to take a test in a more conventional "trusted" institution, as your stay in the country depend on that. Think about what kind of result would US require you to have in order to accept your entrance to the country. I will be doing a little bit more digging, if I find something I will come back and edit the answer.