Cryptosporidium parvum is an opportunistic intracellular apicomplexan parasite that can cause 
life-threatening diarrhea in immunocompromised patients and self-limited diarrhea in healthy 
persons. This study screened Cryptosporidium parvum infection among immunocompromised 
patients versus immunocompetent persons, comparing different diagnostic methods of Cryptos
poridium parvum, and to detect the validity of mini FLOTAC apparatus versus the coproantigen 
ELISA test. A cross-sectional study was carried on two groups: G1:100 immunocompromised 
patients recruited from the National Liver Institute, Oncology Institute, Renal Dialysis Unit, over 
four consecutive seasons. G2: 100 immunocompetent apparently healthy persons. Stool samples 
were divided into two parts, the first part was examined freshly by direct smear and staining 
methods, some mixed with formalin 10% for FECM, and some was used in mini-flotac tech
nique mixed with zinc-sulphate solution. The second part was frozen in (-20) freezer for later 
ELISA copro-antigen technique. The samples were C. parvum oocyst examined by direct smear, 
staining (Iodine and/or Modified Ziehl-Neelsen) and Mini-Flotac apparatus versus C. parvum 
antigen by coproantigen ELISA as a golden standard test.  
The results showed that Cryptosporidium parvum infection by copro-antigen ELISA test was 
25% among all participants (20.5%) in immunocompromised and (4.5%) in immunocompetents 
respectively. Regarding diagnostic tests, direct smear had the lowest sensitivity (14%) for Cryp
tosporidium Parvum detection while the Mini-FLOTAC technique had the highest sensitivity 
(84%) compared to the copro-antigen ELISA method which was 100%.