Advances in Reptilian Hematology and Blood Chemistry
World Small Animal Veterinary Association World Congress Proceedings, 2006
Zdenek Knotek1, DVM, PhD; Zora Knotkova2, DVM, PhD; Sarka Trnkova2, DVM
1Professor, Avian and Exotic Animal Clinic, Faculty of Veterinary Medicine, Univ. Vet. Pharm. Sci. Brno; 2Avian and Exotic Animal Clinic, Faculty of Veterinary Medicine, Univ. Vet. Pharm. Sci. Brno, Brno, Czech Republic

Determination of morphologic characteristic of different peripheral blood cells and plasma chemistry profile of reptiles was the purpose of many studies. Research is still continuing on normal healthy tortoises, lizards, snakes and crocodiles as well as on patients suffering from different metabolic diseases. The results of independent trials show a significant degree of variation due to different animal selection methods and technical differences in blood sample treatment. Blood that is exposed to heparin for several hours will usually not stain as well as slides made immediately after collection. Haemolytic destruction of chelonian cells by EDTA was observed. Classification of white blood cells in reptiles is inconsistent, because variable criteria have been used to categorise these cells. For the more exact characterisation of different types of blood cells in a group of healthy tortoises (Agrionemys horsfieldi) the commercial kits were used (Knotková et al.2000). Ten different types of blood cells were determined: erythrocytes, thrombocytes, lymphocytes, monocytes, type-I cells (heterophils), type-II cells (eosinophils), type-III cells (azurophils), type-IV cells (basophils), type-Ia cells (toxic heterophils) and type-V cells (polychromatophil erythrocytes). Some authors pointed out technical complications involved in distinguishing reptilian small lymphocytes from thrombocytes or big lymphocytes and monocytes (Bruder 1998, Harr et al. 2001). We did not find these problems in reptiles (Pejrilová et al. 2004). Lymphocyte of lizards varies in size between small, uniformly round and large, more pleomorphic mononuclear cells. They are characterized by light-blue to grey-blue cytoplasm and nuclei in the central position, differing--especially in the case of big lymphocytes--considerably in shape. In small lymphocytes, the cytoplasm forms only a tiny rim surrounding the round nucleus. A detailed examination may reveal azurophilic and/or hyaline inclusions. Lymphocytes are the most prolific leukocyte population in peripheral blood of healthy iguanas. The presence of eosinophils varies among species of reptiles. Eosinophils are present in chelonians as well as in crocodilians. Cells which are known as heterophils and eosinophils are present in chelonians. The main difference between them is the shape of granules. Sometime it could be difficult to distinguish the type of granules with the basic Pappenheim´s smears, because the cytoplasm is filled with them. We suggest that Granulocolor® would be appreciated in cases of special importance. Pappenheim method is absolutely sufficient for routine laboratory examination of tortoise's hemogram. One peculiarity typical of green iguanas is the light-blue colour of the round cytoplasmic granules of the eosinophils. The nucleus is round to oval and situated in an off-centre position. The heterophils are characterized by oval or sharpened bright red cytoplasmic granules. The nucleus is bluish, in an off-centre position, mostly segmented. The basophils in reptile blood smears stand out by their exquisite blue granules filling in the cytoplasm and concealing even the nucleus situated in the central position. There is a risk of diluting and washing away basophilic granules in case when inconsiderate sample processing is applied. Inconsistent classification of monocytes and leukocytes with azurophilic granules in the cytoplasm has been a traditional issue in reptile haematology (Saint Girons 1970, Sypek and Borysenko 1988). Even recently, Harr et al. (2001) did not regard the azurophils in green iguana as an independent leukocyte population. Differentiating between the two types of leukocytes in reptiles takes thorough preparation of samples and much experience on the part of the person doing the count. The azurophils are mononuclear cells with a dominantly stained nucleus mostly in an off-centre position and blue-grey cytoplasm containing prominent azurophilic granules. Their shares in peripheral blood differ depending on the reptile genus and species (Campbell 1996).

Most haematological trials focusing on reptiles have had the form of one-off blood sample-taking analysis. Therefore we realised a long-term ontogenetic trial on blood-related lizards kept in identical conditions. The trial involved 11 green iguanas (Iguana iguana rhinolopha) that were kept under special regime of light (12h/12 h), temperature (24-35°C and air humidity (60-80%).

No seasonal changes of the haematological indices were observed, no significant differences in the haematological indices between male and female subpopulations were found (Pejřilová et al. 2004). As to the number of erythrocytes, a statistically significant drop was observed comparing the data at 14 to 15 months of age with those at 34 to 36 months. We recorded a statistically significant drop in packed cell volume comparing the figures at 14 to 18 months with those obtained at 34 to 35 months of age of the animals. Our results confirmed a statistically significant rise in haemoglobin concentration comparing the data at 23 to 24 months with those at 35 to 36 months. A similar statistically significant rise was confirmed for computed red cell indices (MCV, MCH, MCHC), too.

Plasma chemistry profile in reptiles involves analysis of well separated plasma for the concentration of total protein, glucose, uric acid, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, cholesterol, triglycerids, calcium and phosphorus. The hyperuricaemia may indicate renal damage in reptiles, but uric acid levels do not increase significantly until the extensive damage of kidney. Hyperphosphataemia seems to be more reliable indicator of renal insufficiency in iguanas (Knotek et al. 2002). Indeed, the phosphorus-calcium ratio could be a sensitive parameter for the diagnosis of renal disease. Results of our previous studies show a significant degree of variation in plasma chemistry of green iguanas. Females with post-ovulatory egg stasis or pre-ovulatory follicle stasis had the highest mean plasma values for uric acid and phosphorus compared to females with acute hypocalcaemia and females with metabolic bone disease. Females with acute hypocalcaemia had the highest concentration of AST, the highest phosphorus to calcium ratio and the lowest plasma concentrations of total protein, glucose, cholesterol and calcium (Knotek et al. 2003). The peripheral blood concentrations of calcium, cholesterol and triglycerides may correspond to the metabolic activity requirement, which is lower in adult males than in females during the breeding season. Calcium levels in peripheral blood of green iguana females peak within the period of vitellogenesis. In ovariectomized females we revealed downward trend for examined values reaching the levels typical for males. During the following reproductive season intact females returned to the vitellogenic high concentrations of calcium, cholesterol and triglycerides whereas ovariectomized females did not (Knotková et al. 2005). The mechanism of hormonal control (oestrogen levels) for seasonal changes of calcium, cholesterol and triglycerid levels in blood of female green iguana is expected.

Table 1. Plasma chemistry values in iguanas with renal disease.



Boyer et al.

Knotek et al. 2002
Mean ± SD

Total protein



53.51 ± 15.96




10.07 ± 6.81

Uric acid



306.70 ± 212.88




61.07 ± 24.78




0.38 ± 0.33




0.74 ± 0.64




5.02 ± 5.82




5.29 ± 3.62




4.18 ± 0.33




2.06 ± 0.78




5.95 ± 3.21

Table 2. Plasma chemistry values in females green iguana.







7.59 ± 3.34

3.55 ± 3.10

2.75 ± 0.20

2.11 ± 0.13


10.13 ± 3.46

6.44 ± 2.68

6.03 ± 2.24

2.60 ± 0.40


12.42 ± 4.74

2.40 ± 2.62

2.98 ± 0.60

1.75 ± 5.21


7.50 ± 3.15

5.32 ± 2.84

3.00 ± 0.20

2.76 ± 0.45


15.75 ± 1.47

15.62 ± 0.50

7.01 ± 1.67

6.91 ± 1.37


12.24 ± 4.63

10.03 ± 2.57

7.67 ± 1.30

3.37 ± 1.47


1.  Bruder M Blutreferenzwerte bei Grünen Leguanen (Iguana iguana). Thesis, Univ München, 1998, 113.

2.  Campbell TW Clinical pathology. In: MADER DR (Ed).: Reptilie Medicine and Surgery. WB Saunders, Philadelphia, 1996, 248-257

3.  Divers SJ, Redmayne G, Aves EK Haematological and biochemical values of 10 green iguanas (Iguana iguana). Vet Record, 1996, 138: 203-205.

4.  Harr KE, Alleman AR, Dennis PM, Maxwell LK, Lock BA, Bennet RA, JAcobson ER Morphologic and cytochemical characteristics of blood cells and hematologic and plasma biochemical reference in green iguanas. J Amer Vet Med Assoc, 2001, 218: 915-921.

5.  Hawkey CM, Dennett TB Color atlas of comparative veterinary hematology. Wolfe Medical Publ, 1989, 192.

6.  Knotek Z, Hauptman K, Knotková Z, Hájková P, Tichý F Haemogram and Plasma Biochemistry in Green Iguanas with Renal Disease. Acta Veterinaria Brno, 2002, 71: 333-340

7.  Knotek Z, Knotková Z, Doubek J, Pejřilová S, Hauptman K Plasma Biochemistry in Female Green Iguanas (Iguana iguana) with Calcium Metabolism Disorders. Acta Veterinaria Brno, 2003, 72: 183-189.

8.  Knotková Z, Knotek Z, Hájková P. Plasma biochemistry of chelonians of the Geochelone group. Proc.3rd EAZWV Sci. Meeting, 31.5.-4.6. 2000, Paris, 281-285.

9.  Knotková Z, Pejřilová S, Trnková Š, Matoušková O, Knotek Z. Influence of Reproductive Season upon Plasma Biochemistry Values in Green Iguanas. Acta Veterinaria Brno, 2005, 74: 515-520.

10. Köhler G. Krankheiten der Amphibien und Reptilien. Eugen Ulmer Vrlg, 1996, 166.

11. Saint Girons MC Morphology of the circulating blood cells. In: Gans C, Parsons TS (Ed): Biology of the Reptilia, vol. 3--Morphology C, Academic Press London, 1970, 73-91.

12. Pejřilová S, Knotková Z, Knotek Z, Vrbas J Age-Related Changes of the Haematological Profile in Green Iguana (Iguana iguana rhinolopha). Acta Vet Brno 2004, 73: 305-312.

13. Sypek J, Borysenko M Reptiles. In: Rowley AF, Ratcliffe NA (Ed): Vertebrate blood cells. Cambridge Univ Press, Cambridge, 1988, 211-256.

14. Walton RM. Establishing Reference Intervals. Health as a relative Concept. Seminars in Avian and Exotic Pet Medicine, 2001, 10: 66-71.

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Zdenek Knotek, DVM, PhD
Avian and Exotic Animal Clinic
Univ. Vet. Pharm. Sci. Brno
Brno, Jihomoravský kraj, Czech Republic

Zora Knotkova, DVM, PhD
Avian and Exotic Animal Clinic
Univ. Vet. Pharm. Sci. Brno
Brno, Jihomoravský kraj, Czech Republic

Sarka Trnkova, DVM
Avian and Exotic Animal Clinic
Univ. Vet. Pharm. Sci. Brno
Brno, Jihomoravský kraj, Czech Republic

MAIN : Exotics : Reptilian Hematology
Powered By VIN