It is the International Athletics Federation's integrity unit AIU (Athletics Integrity Unit) that appealed the independent panel's acquittal last month, several international news agencies write.
The anti-doping agency Wada was also prepared to take the case to Cas.
"I'm worried about Salwa Eid Naser and the panel's decision.
Wada will analyze it carefully and exercise its right to appeal if necessary ", tweeted Wadachefen Witold Banka when the panel's acquittal decision came.
Had four misses in the stay reporting
The Bahrain runner, who won the World Cup in Doha last year at the world's third best time of all time, 48.14, had missed in his stay reporting.
According to the regulations, three mistakes in the stay reporting within one year can lead to a two-year suspension, the minimum penalty is one year.
Eid Naser had his misses on 12 and 16 March 2019 and 24 January 2020, making three misses in less than a year.
But the test on March 16 is technically counted as the beginning of the quarter, ie on January 1.
This means that the three missed tests count for just over a year and are therefore not punishable.
In addition, there is a fourth suspected case regarding Eid Naser's stay reporting, something that happened on April 12, 2019. However, the doping hunter could not get hold of Eid Naser after a series of misunderstandings about telephone number and address in his hometown Riffa.
The AIU wanted to count it as a miss but the independent panel dismissed it.
Normally, it takes Cas several months to prepare a case of this dignity.