Sudan's giants protested when eight of their first team players returned positive tests ahead of the tie in the city.
Al Merreikh had made a complaint to CAF regarding the outcome where eight of their players had tested positive before the March 16 encounter in Dar es Salaam.
Simba went ahead to win the game 3-0 as their Group A rivals headed to CAF after results indicated Abdelrahman Isaac, Bakhit Khamis, Ahmed Abdelmoneim, Tajeddin Yaqoub, Ramadan Ajab, Tony Edjomariegwe, Bakri Al Madina, and Saif Ad Damazin were COVID-19 positive.
"We acknowledge the complaint of the Al Merreikh Club dated March 21 2021 as well as the correspondences of your lawyer Ahmed Abbas El Mag and his powers of attorney," a statement by CAF as seen by The Guardian read.
The CAF noted: "We would like to hereby confirm that Al Merreikhs' complaint regarding match number 101 of the CAF Champions League is well-received however, as per the current rules and procedures the FAQs for the return of football states that, 'The mandatory PCR test should be conducted no earlier than 48 hours before the match participants access the stadium'''.
"The tests conducted before the match is the official that is taken into consideration for the eligibility of the players. As you are aware, the results of the tests can vary from one day to the other.''
"Furthermore, several players from Simba tested positive as well as some CAF officials.''
"We would like to hereby inform you that CAF has made some investigations regarding the testing procedures in Tanzania, and the investigations revealed that the laboratory does not issue or print any certification for positive cases.''
"Certification is only provided for the negative COVID-19 cases. The positives ones are communicated through the established channels for various individuals and organizations.''
"Thereby, we would like to confirm that the COVID-19 tests that were communicated to CAF are the ones to be taken into consideration for the tie in the frame of CAF Champions League."
Simba's 3-0 victory over Al Merreikh helped the former keep top spot in a group that also consists of Egypt's Al Ahly and AS Vita Club of Democratic Republic of Congo (DRC).
The Msimbazi Street club will face AS Vita Club, a squad the former beat 1-0 at their own turf, at Benjamin Mkapa Stadium on April 3.
Simba will thereafter confront second-placed Al Ahly in Egypt six days later.
With just a win and three losses, AS Vita are placed third while Al Merreikh are at the bottom with a draw and three losses.