Sadly, taking coronavirus tests has become almost a requirement for international travel. Test requirements may vary depending on the country you are traveling to or transiting through.
An important requirement for all coronavirus tests, regardless of their type, is the expiration date. In most cases, this is 72 hours for classic molecular tests carried out using real-time polymerase chain reaction (RT-PCR), or 48 hours for rapid tests, say LAMP or antigen tests. In this publication we will tell you how to calculate the expiration date of coronavirus tests.
We assume that we are taking the test for a practical purpose: so that we will be allowed to board the plane or be allowed to enter the country. This means that we will calculate the optimal time for taking the test based on the time it takes to check the result.
Time to board a flight or arrive in the country
This is the time when the test will be checked — at this point the test must be valid. There are 3 options:
- check-in time for a flight into the country,
- check-in time for the first flight on the route to the country. Depends on the airline's requirements,
- time of arrival in the country. Typically, this refers to the time it takes to clear passport control upon arrival.
In particular, Mexico City — Istanbul — Frankfurt, the test is needed for Germany, but you will be asked to show it when landing in Mexico City.
Another example: Mexico City — New York — Istanbul, tests are needed for both the USA and Turkey. Although it is cheaper for the US to do an antigen test, it will not be accepted in Turkey. Therefore, it is more rational to do a PCR test, which will be valid for 72 hours and is suitable for both the USA and Turkey. They will be asked to show the test in both Mexico City and New York.
Time to take the test
The expiration date of the test is calculated from the time the biological sample (smear) was taken for analysis, and not from the time you received the test result.
This time must be indicated in the test results. No matter how it is designated (Reception, Run Date, Date Sampled or whatever else), this will be the earliest time indicated on the result. In our image, the sampling time is indicated by the number 3 in the red circle.
If you took a PCR test, which most often takes almost 24 hours, after purchasing its result you will have approximately 2 more days, rather than 72 hours, for the test to remain valid.
Test expiration date
The actual expiration date of a coronavirus test is calculated as the time difference between two events — the time of swab collection and the time of boarding the flight.
Count back 72 hours from the time of landing or arrival, and you will get the time NOT BEFORE which you need to take the coronavirus test. The later you take the test after the estimated time, the longer its expiration date will be. However, part of the expiration date will be spent running the test in the laboratory before they give it to you.
Add 72 hours to the time the sample is taken for testing, and you get the deadline until which the test will remain valid. Take into account the time difference between departure and arrival airports!
If you are flying west:
- time when the test will be checked
- minus72 hours
- plusthe time difference between the city where the test will be tested and the city where you will take the test.
If you are flying east:
- time when the test will be checked
- minus72 hours
- minusthe time difference between the city where the test will be tested and the city where you will take the test.
As a result of the calculations, we get the time before which the test does not need to be taken. The closer to the time of departure you receive the test result, the calmer you will be.
Some countries and airlines allow the test's shelf life to be extended to 96 hours if arrival in the country is late due to a flight delay caused by the airline.