Knowledge of suitable methods and reagents for assessing the health condition of specimens of a given species is essential. The present study evaluated the efficacy of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA, and K3EDTA on the blood parameters of yellow-spotted amazon river turtle Podocnemis unifilis, employing different solutions for red blood cells count. The use of the various anticoagulants evaluated after 10 hours of storage efficiently inhibited coagulation in blood samples from P. unifilis. An increased number of erythrocytes was observed with the use of K3EDTA 5% when compared with heparin. Statistically significant changes in the erythrocyte number were observed with the use of the different solutions. Solutions which featured sodium citrate and formaldehyde in their composition, allowed erythrocytes counting up to 120 hours after blood collection, without a change in values. The use of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA 3%, Na2EDTA 5%, K3EDTA 3% was recommended in the hematological analysis of P. unifilis. Also recommended was the use of the formaldehyde-citrate solution containing 1.9 g of sodium citrate and 1.0 mL of formaldehyde (in 50 mL of distilled water) to perform red blood cells counts in yellow-spotted amazon river turtle.