Introduction: The change of blood group on the spot is when the non-O blood groups, namely A, B and AB, are found to be blood group O (false), this can occur one of them because of the long time of scattered blood (blood stains) found at the scene of the crime, so it can cause blood stains to be contaminated by mycoorganisms. One microorganism known to easily contaminate bloodstains is Aspergillus flavus. This can lead to the degradation of contaminated bloodstains because the contents in the blood can be used by microorganisms as their metabolic material. Objective : This study examines whether there is an effect of incubation time on changes in blood group in blood spots contaminated with Aspergillus flavus, this study uses blood spots of blood group A and blood group B contaminated with Aspergillus flavus. Method : This study was conducted in vitro and is an experimental study using a one-group pretest-posttest design. Blood spots contaminated with Aspergillus flavus were treated with an incubation period of 1 week, 2 weeks, 3 weeks and 4 weeks.  Changes in blood group were then identified using the absorption-elution method. Results : The results of the study as many as 30 units of blood spots of blood group A and blood group B contaminated with Aspergillus flavus did not change the blood group because it can still be identified antigens that match the blood group of the insect at week 4 seen from the occurrence of agglutination. Conclusions : The conclusion that can be drawn from this study is that blood spots of blood groups A and B contaminated with Aspergillus flavus do not change blood groups during incubation times of 1 week, 2 weeks, 3 weeks and 4 weeks or 28 days.

Doty, Kyle C., Gregory McLaughlin, and Igor K. Lednev. 2016. “A Raman ‘Spectroscopic Clock’ for Bloodstain Age Determination: The First Week after Deposition.” Analytical and Bioanalytical Chemistry 408(15):3993–4001. doi: 10.1007/s00216-016-9486-z.

Faruq, Zulfikar Husni. 2015. “Modul 3: Serologi Golongan Darah.” Banten: Poltekkes Jakarta 3.

Indah, Sari, Bastian, and Nurul Pathia. 2022. “Analisa Pengaruh Waktu Terhadap Perubahan Golongan Darah Pada Sampel Bercak Darah.” Jurnal Riset Kesehatan Poltekkes Depkes Bandung 14(1):167–72. doi: 10.34011/juriskesbdg.v14i1.2024.

Kachuri, A. .., A. M. Golubev, M. M. Geisow, O. S. Veselkina, L. S. Isaeva-Ivanova And, and K. N. Neustroev. 1995. “Role of Methionine in The Active Site of Alpha_Galactosidase From Rhizopus Stolonifer and Aspergillus Flavus.” J. Biochem 1995 308 (Pt 3): 955-964.

Kubo, S. 1989. “Changes in The Specificity of Blood Groups Induced by Enzymes From Soil Fungi.” J. Foren Sci volume 34.

Kulkarni, U. K., N. R. Gosavi, and K. V Kulkarni. 2016. “Effect of Ageing and Environment of North Maharashtra on ABO Grouping Substances of Blood Stain.” Journal of Pharmaceutical, Chemical and Biological Sciences 3:608–11.

Li, Richard. 2015. Forensic Biology Second Edition John Jay College of Criminal Justice. 2nd ed. Ney York.

Masyrur, Muhamad, I. Ketut Junitha, and Meitini W. Proborini. 2019. “Perubahan Golongan Darah Berdasarkan Pengaruh Waktu Dan Mikroorganisme Yang Berperan.” Metamorfosa: Journal of Biological Sciences 6(2):165. doi: 10.24843/metamorfosa.2019.v06.i02.p05.

Olsson, Martin L., and Henrik Clausen. 2007. “Modifying the Red Cell Surface: Towards an ABO-Universal Blood Supply.” British Journal of Haematology 140(1):3–12. doi: 10.1111/j.1365-2141.2007.06839.x.

Suryadi, Taufik. 2015. “Teknik Analisis Dna Dalam Mengidentifikasi Genotip Golongan Darah Pada Jenazah Kasus Forensik.” Jurnal Kedokteran Syiah Kuala 15(3):157–61.

Susilo, Bagas, I. Ketut Junitha, and Yan Ramona. 2020. “Perubahan Golongan Darah Dan Identifikasi Bakteri Yang Berperan Dalam Merubah Golongan Darah.” Metamorfosa: Journal of Biological Sciences 7(1):96. doi: 10.24843/metamorfosa.2020.v07.i01.p13.