Introduction: Aspergillosis is a type of fungal infection or a type of mold that can cause serious respiratory illnesses in people especially those with weakened immune systems. Timely diagnosis and treatment of Aspergillus infections is critical to preventing potentially life-threatening complications. It can be difficult to diagnose, as it often mimics other diseases. Cytopathology and microbiology lab techniques can be used to help diagnose aspergillosis; Histopathology, PCR and biochemistry are also important. Aims: To compare the most effective laboratory diagnostic techniques to detect the Aspergillus in body. Methods: This systematic review searched for studies that evaluated the use of cytopathology and microbiology and other lab techniques in the diagnosis of aspergillosis. Studies were identified through searches of Google Scholar, MEDLINE, EMBASE, and the Cochrane Library. Results: Cytopathology and microbiology lab techniques can both be helpful in diagnosing aspergillosis. Cytopathology and histopathology are both highly accurate, but results may take longer to obtain than with other tests. Microbiology is useful for diagnosing infections, but it may not be as accurate as cytopathology or histopathology. Poly Chain Reaction (PCR) is very accurate, but it is also expensive and results may take some time to obtain. Biochemistry can be useful for diagnosing metabolic disorders, but it is not as accurate as other tests. Conclusion: There is no one “best” way to detect Aspergillus, and the best approach may vary depending on the particular patient and situation. In general, a combination of two or more tests may be needed to accurately diagnose aspergillosis. The most important factor/guideline in choosing which tests to use is whether they will provide information that can help guide treatment decisions. Nevertheless, with all factors considered the PCR is the best test because it is highly sensitive and specific; able to detect even low levels of Aspergillus.