Introduction: Reliability of biological assays results depends closely on the quality of the 3 biological stages: pre-analytical, analytical, and post-analytical. In each stage, a quality program including internal quality control (IQC) and external quality assurance (EQA) has to be assessed to ensure test result accuracy and precision. The coagulation laboratory plays an important role in the diagnosis and treatment of people with blood disorders, so though several lack of facilities in Malagasy labs, QC has to be implemented. Thus, this study aimed to analyze IQC and EQA in hemostasis tests in the Hematology laboratory of the CHU-HJRA in Antananarivo Madagascar in order to improve its analytical phases quality. Methods: This retrospective descriptive and analytical study was conducted from January 1st, to October 31st, 2021 in the Hematology laboratory of CHU-JRA within the routine coagulation tests (Prothrombin time PT and Activated partial prothrombin time aPTT). Regarding the EQA, percentage of deviation from the peer groups results were calculated. Then in order to analyze IQCs results, coefficient of variation and biases of IQCs results, corresponding respectively to precision and accuracy, were calculated and Levey-Jennings graphs were analyzed. Results: Regarding global results of EQA, 50% were within consensus compared to peer-group. And regarding IQC, for precision, one coefficient of variation for both PT and aPTT exceeded 5%, and for accuracy, no bias exceeds 10% deviation from the expected result. Levey-Jenningss plot showed more than 90% of the results to be within M±2 SD range. A violation 10x Westgard rules, corresponding to a systematic error was observed. Conclusion: Each out-of-control results has to be analyzed as part of strengthening quality program guaranteeing coagulation tests reliability.