Video
Video 1. This video was produced by Katie Lennox-Phillibeck and narrated by Dr. Angela Lennox. An embedded clip on jugular venipuncture was contributed by Dr. Marco Di Giuseppe.
The video script was written by Dr. Christal Pollock and reviewed by Drs. Byron de la Navarre, DVM, Alyssa Scagnelli, DVM, and Anneliese Strunk. More detailed information is available in the text below, as well as a brief video illustrating jugular transillumination and venipuncture in a chameleon shared by Dr. Charly Pignon.
Introduction
Hematology and biochemistry results are an important part of the minimum database for all veterinary patients, including lizards. Proper venipuncture technique is critical for accurate interpretation of laboratory results.
Equipment needed
To collect the sample, you will need:1,8,19,22
- Antiseptic (Fig 1)
- Glass slides and hematocrit tubes
- A 22-27-gauge needle attached to a 1 or 3-ml syringe (or insulin syringe). The length of the needle will vary with the size of the animal, and a long needle is often required to collect samples from large lizards.
- Anticoagulant tubes: Many clinical practices routinely use lithium heparin for reptile hematology. However, research has identified species in which sodium ethylenediamine tetraacetic acid (EDTA) works or is even superior to heparin, such as the green iguana (Iguana iguana) and Chinese water dragon (Physignathus cocinus).12,16
- A butterfly catheter can be useful to obtain samples from areas prone to movement, like the tail.
- Disposable gloves to minimize the risk of zoonotic disease
Visit “General Principles of Reptile Venipuncture” for advice on sample handling, use of anticoagulants, and recommended sample volume.

Figure 1. With even the most scrupulous sanitation, lizards frequently sit in or walk through their own droppings. To minimize the risk of needle site contamination with bacteria or uric acid, aseptically prepare the venipuncture site with an antiseptic. Photo credit: Dr. Charly Pignon. Click image to enlarge.
Handling and restraint
Two people are typically required for venipuncture in lizards. One person restrains the animal while the phlebotomist collects the sample. Sedation may be required for large or intractable patients.21 Ketamine, alfaxalone, or alpha-2 agonists, like dexmedetomidine, can be used to chemically restrain the lizard.20
Venipuncture sites
Blood samples can be collected from a variety of sites in the lizard (Fig 2), including the axillary plexus, brachial vein, heart, cranial vena cava, jugular vein, orbital sinus, ventral abdominal vein, and ventral coccygeal vein (Fig 3, Fig 4) (Table 1).1–10,13,15,18,19,21 Samples are most frequently collected from the ventral coccygeal vein and the jugular vein.1,13,18,19

Figure 2. There are a variety of venipuncture sites in the lizard but blood samples are most frequently collected from the ventral coccygeal vein and jugular vein. Image credit: Katie Lennox-Phillibeck. Click image to enlarge.

Figure 3. Collection of blood from the cranial vena cava has been described in leopard geckos (Eublepharis macularius) and crested geckos (Rhacodactylus ciliates). Photo credit: Dr. Sean Perry. Click image to enlarge.

Figure 4. Collection of blood from the jugular vein of a chameleon. Photo credit: Dr. Charly Pignon. Click image to enlarge.
Table 1. Venipuncture sites described in the lizard | |||||
---|---|---|---|---|---|
Vessel | Landmarks | Advantages | Limitations | Comments | References |
Axillary plexus | Near the shoulder joint at the caudal aspect of the humerus | Lymph dilution can occur1,15 | Described as the brachial plexus by Brown (2007)1 | 1,8,15,21 | |
Brachial vein | Often lymph diluted | Blind approach | 2 | ||
Cardiocentesis | Cardiac position is highly variable in lizards and a Doppler flow monitor can be useful in small lizards | The sample is generally free of lymph | Generally considered an unacceptable route due to the potential for injury and hemorrhage since the lizard heart cannot be stabilized as it is in snakes1,6,8 | Utilized in crested geckos* in a laboratory setting. The animals were monitored for over 1 year afterwards and “showed no ill effects”17 | 1,5,6,8,17,21 |
Cephalic vein | 19 | ||||
Cranial vena cava | This blind technique was used in leopard geckos** under isoflurane anesthesia 11 and in crested geckos* using manual restraint17 | 4,11,17 | |||
Jugular vein | Between the point of the shoulder and the tympanum or ear scale | Lymph contamination is often less likely | Often performed as a blind technique, which increases the risk of soft tissue injury | Transillumination has been used in chameleons10 | 1-3,6,7,10,1819 |
Orbital sinus | 8,21 | ||||
Ventral abdominal vein | Located on ventral midline within a suspensory ligament just beneath the linea alba | Risk of vessel and visceral lacerations with subsequent uncontrolled hemorrhage or intracoelomic contamination | Often a blind technique although a transilluminator can be useful in some small species | 1,5,18,19,21,23 | |
Ventral coccygeal vein | Ventral or lateral midline of the tail, approximately one-fourth the length of the tail caudal to the vent | Accessible in most lizards | Avoid or use caution in species with tail autotomy | The most common venipuncture site in the lizard | 1,3,4,12,14,15,16,19 |
*Crested gecko (Rhacodactylus ciliates) **Leopard gecko (Eublepharis macularius) |
Ventral coccygeal vein
The ventral coccygeal vein or “tail vein” is the most commonly used vessel in lizards.5,8,21 The tail vein extends along the ventral surface of the coccygeal vertebral bodies and is partially protected by the ventral spinous processes.1
Potential complications
Care must be exercised in species with tail autotomy 2,5, and some reptile veterinarians avoid this site all together in species, such as iguanids and geckos.6 If coccygeal venipuncture is utilized in a species with the ability to shed the tail, risk may be minimized by monitoring the tail closely and aborting the procedure if tail twitching is observed.4 If venipuncture is attempted too close to the vent there is also a risk of puncturing the hemipenes in male lizards.5 Lymphatic contamination may also occur.8

Figure 5. The leopard gecko (Eublepharis macularius) is a species that practices tail autotomy, presumably as a defensive mechanism. Photo credit: Katie Lennox-Phillibeck and Dr. Angela Lennox. Click image to enlarge.

Figure 6. Dropped tail from a leopard gecko (Eublepharis macularius). Photo credit: Katie Lennox-Phillibeck and Dr. Angela Lennox. Click image to enlarge.
Venipuncture of the tail vein is a blind technique and the rate of failure to obtain a useful sample can be significant.3,10,14 In a study comparing venipuncture sites in the common chameleon (Chamaeleo chamaeleon), only 67% (34/51) of venipuncture attempts from the ventral tail were successful.10 Even when a sample is obtained, difficulty during sample collection can lead to soft tissue damage and transient darkening of the skin.3,10,14
Location
The recommended venipuncture site is approximately one-fourth the length of the tail caudal to the vent. Of course the best venipuncture site will vary by species and the ideal site can range between 20% to 80% down the tail.5,8 The tail vein can be accessed either ventrally or laterally.22
Equipment
Select a needle that is long enough to be able to reach the ventral vertebral processes.1 When accessing the “tail vein” by the ventral approach, a 13 mm (0.5-in) needle will often suffice in smaller patients but a needle measuring at least 25-50 mm (1-1.5 in) will be required for most medium-sized to large lizards.1 The lateral approach requires a shorter needle than the ventral approach.1
Ventral approach
To perform the ventral approach:1,2,4,5,8,10,19,22
- Restrain the lizard in dorsal recumbency.
- The phlebotomist uses their non-dominant hand to pin the hind legs beside the tail. The dominant hand is used to collect the blood (Fig 7, Fig 8).
- Aseptically prepare the venipuncture site.
- Insert the needle directly on ventral midline at a 45 to 60-degree angle between two ventral scales (Fig 9).
- Once the needle is through the scales, direct the needle at a 90-degree angle towards the tail OR in a craniodorsal direction.
- Maintain gentle negative pressure as the needle is advanced.
- Once blood appears in the needle hub, hold the needle steady while continuing to apply gentle negative pressure (Fig 10).
- If the needle reaches a ventral vertebral process without getting a flash of blood, then very slowly withdraw a few millimeters while maintaining negative pressure.
- It may be necessary to withdraw the needle and redirect slightly. If a flash is noted but stops, gently rotate the needle and syringe while applying very gentle negative pressure and moving the needle and syringe in tiny increments towards and away from the vertebrae until a better flow of blood is observed.
Some large lizards possess extremely tough, semi-calcified scales along the ventral tail surface that prevent easy insertion of a needle. Consider the lateral approach in these patients.1

Figure 7. The phlebotomist uses their non-dominant hand to pin the rear limbs beside the tail. Photo credit: Dr. Charly Pignon. Click image to enlarge.

Figure 8. Alternatively, the handler can restrain the rear limbs allowing the phlebotomist to focus on grasping the tail base in the non-dominant hand. Photo credit: Katie Lennox-Phillibeck and Dr. Angela Lennox. Click image to enlarge.

Figure 9. Insert the needle directly on ventral midline at a 45 to 60-degree angle between two ventral scales. Photo credit: Dr. Charly Pignon. Click image to enlarge.

Figure 10. Once blood appears in the needle hub, hold the needle steady while continuing to apply gentle negative pressure. Photo credit: Dr. Charly Pignon. Click image to enlarge.
Lateral approach
In the lateral approach, the needle is inserted on the lateral midline and directed just beneath the lateral processes of the coccygeal vertebrae.1,2,4,5,8,10,22 The lateral approach can be particularly useful for larger lizard species.8 Some individual patients also better tolerate this approach since they are allowed to remain in sternal recumbency, however, lymph dilution may be more likely (Fig 11).8

Figure 11. Lateral approach to the ventral coccygeal vein is sometimes better tolerated because the patient can remain in sternal recumbency. Photo credit: Dr. Marco Di Giuseppe. Click image to enlarge.
Step-by-step technique1,8,22
- Restrain the lizard in sternal recumbency.
- The lateral midline can be identified by a longitudinal groove where the dorsal and ventral coccygeal muscle groups meet. This landmark can be difficult to identify in overweight lizards.
- Aseptically prepare the venipuncture site.
- Insert the needle at a 90-degree angle to the tail OR advance the needle at a 45 to 60-degree angle in a craniomedial direction (Fig 12, Fig 13).
- Maintain gentle negative pressure as the needle is advanced.
- If the needle contacts bone, slowly shift the needle ventrally in very small increments while maintaining negative pressure.

Figure 12. To approach the ventral coccygeal vein laterally, the needle can be inserted perpendicular to the tail. Photo credit: Katie Lennox-Phillibeck and Dr. Angela Lennox. Click image to enlarge.

Figure 13. Alternatively, the needle can be advanced in a craniomedial direction at a 45 to 60-degree angle. Photo credit: Katie Lennox-Phillibeck and Dr. Angela Lennox. Click image to enlarge.
Jugular vein
Experienced reptile veterinarians also sometimes utilize the jugular vein.1–3,6,7,10,19 The vessel is sizable and relatively large volumes of blood can be collected with little lymphatic fluid dilution.6 In a survey of 51 samples collected from common chameleons, none of the samples appeared to be hemodiluted.10
Jugular venipuncture has historically been recommended in larger lizards, such as monitors and iguanas.1,2,8 More recently, the technique has been employed in small lizards, such as agamids, chameleons, lacertids, and geckos, weighing less than 100 grams.3,6,7
Anatomical landmarks
The jugular veins lie lateral and deep and are rarely visible even when caudally occluded by digital pressure.1,2,8,19 To locate the jugular vein, draw an imaginary line between the point of the shoulder and the tympanum or ear scale.1,8,18,19 The jugular vein lies caudal to the ramus of the mandible or the tympanum and courses caudoventrally toward the point of the shoulder (Fig 14-Fig 16). In chameleons, an extension of the jugular vein, called the casque vein, can also be accessed behind the casque as it courses vertically along the inside of this bony structure.9

Figure 14. Gross anatomy image illustrating the jugular vein in a gecko. Photo credit: Dr. Marco Di Giuseppe. Click image to enlarge.

Figure 15. Gross anatomy image with overlay and arrows indicating the jugular vein in a gecko. Photo credit: Dr. Marco Di Giuseppe. Click image to enlarge.

Figure 16. Diagram illustrating the jugular veins (REJV, LEJV) in a small lizard. Image credit: Dr. Marco Di Giuseppe. Click image to enlarge.
Potential complications
Jugular venipuncture can pose technical challenges and when using the blind technique there is a risk of causing pain and soft tissue injury to major cervical anatomical structures, such as the carotid artery and vagus nerve.10 Hemodilution is less common with jugular venipuncture but it is also possible.
Blind technique
Jugular venipuncture is often a blind technique.1–3,6,7,10
- Restrain the lizard in lateral recumbency with the head and neck slightly extended (Fig 17).
- Di Guiseppe (2017) recommends placing the index and middle fingers behind the head, in contact with mandibular branch.6
- The right jugular vein is usually larger than the left. Slightly rotate the head to the left to better expose the jugular vein.
- To locate the jugular vein, draw an imaginary line between the point of the shoulder and tympanum.
- Aseptically prepare the venipuncture site.
- Insert the needle behind the tympanum at an angle less than 45-degrees while applying gentle negative pressure .
- Direct the needle in a caudal direction along the imaginary line towards the point of the shoulder (Fig 18).

Figure 17. Restrain the lizard in lateral recumbency with the head and neck slightly extended. Photo credit: Dr. Marco Di Giuseppe. Click image to enlarge.

Figure 18. Direct the needle in a caudal direction towards the point of the shoulder while applying gentle negative pressure. Photo credit: Dr. Marco Di Giuseppe. Click image to enlarge.
Transillumination
The transillumination method relies upon visualization of the jugular vein in a restrained chameleon by backlighting the cervical region (Video 2, Fig. 19).10 Any bright, concentrated light source can be used, such as a penlight, flashlight, or transilluminator.10 Directly viewing the vein using transillumination allows the angle of needle insertion to be adjusted as needed (Fig 20, Fig 21).1 Since the jugular vein lies relatively close to lymphatics in the common chameleon (Chamaeleo chamaeleon), Eshar (2018) also recommends creating an approximate 45-degree bend in the needle to reduce the risk of hemodilution.10
Video 2. Jugular transillumination and venipuncture in a chameleon. Video shared by Dr. Charly Pignon.

Figure 19. Transillumination of the cervical region in a chameleon. Image credit: Dr. Charly Pignon. Click image to enlarge.

Figure 20. The angle of needle insertion is informed by directly viewing the vein via transillumination, but is often approximately 45 degrees. Photo credit: Dr. Charly Pignon. Click image to enlarge.

Figure 21. When blood appears, hold the needle steady while continuing to apply gentle negative pressure. Photo credit: Dr. Sean Perry. Click image to enlarge.
The transillumination technique has been reported to provide more accurate venipuncture, increased sampling success, and reduced handling time, while minimizing soft tissue damage.10 In a survey of 40 chameleons, the transilluminated jugular venipuncture technique was successful in all animals.10 The smallest chameleon to be sampled from the jugular vein using this technique weighed only 13 grams.10
Ventral abdominal vein
Lizards possess a large ventral abdominal vein that lies within a suspensory ligament just beneath the linea alba.1,5,8,9 The ventral abdominal vein is formed by the joining of the pelvic veins, hypogastric veins, as well as a single ventral pubic vein.1,8,9 At the level of the umbilicus, the ventral abdominal vein begins to dive dorsally and joins with the hepatic vein.1
Anatomical landmarks
The ventral abdominal vein is located on ventral midline between the umbilical scar and pelvic inlet.5,18
Potential complications
The ventral abdominal vein is an extremely fragile vessel and there is the potential for intracoelomic hemorrhage if the vein is lacerated.1,5,23 This hemorrhage can be uncontrolled since it is difficult to apply pressure to the vessel.1,8 There is also the risk of visceral lacerations and contamination of the coelom if the gastrointestinal tract or bladder is punctured.1,8,23
Technique
Venipuncture of the ventral abdominal vein is generally a blind technique, although a transilluminator can assist visualization of the vessel in some smaller species (Fig 23).1 Due to the potential risks, the patient should be anesthetized.1
- Aseptically prepare the venipuncture site.
- Approach the vessel in the midcoelomic region, at or just proximal to the umbilicus (Fig 22).1,8
- Insert the needle at a 15 to 45-degree angle.1
- Apply gentle negative pressure once the needle is inserted and advance the needle in a craniodorsal direction.8,18

Figure 22. Cannulation of the ventral abdominal vein in a green iguana (Iguana iguana). Photo credit: LafeberVet. Click image to enlarge.

Figure 23. Collection of blood from the ventral abdominal vein enhanced with the use of a bright light source. Photo credit: Dr. Marco Di Giuseppe.
Summary
The venipuncture site selected can depend on a variety of factors including the preferences and experience of the phlebotomist, the volume of blood needed, patient size and temperament, and of course the species involved. Blood samples are most frequently collected from the ventral coccygeal vein and jugular vein in lizards.
Acknowledgements: Thank you to Drs. Charles Innis and Stacey Leonatti Wilkinson for helpful feedback.
References and further reading
References
1. Brown C. Blood sample collection in lizards. Lab Anim 2007;36(8):23. doi: 10.1038/laban0907-23.
2. Campbell TW. Blood sample collection and preparation in reptiles. In: Exotic Animal Hematology and Cytology, 4th ed. Ames, IA:John Wiley & Sons. 2015:282-291.
3. Cuadrado M, Molina-Prescott I, Flores L. Comparison between tail and jugular venipuncture techniques for blood sample collection in common chameleons (Chamaeleo chamaeleon). Vet J. 2003;166(1):93-97. doi: 10.1016/s1090-0233(02)00253-8. PMID: 12788022.
4. Cojean O, Alberton S, Froment R, Maccolini E, Vergneau-Grosset C. Determination of leopard gecko (Eublepharis macularius) packed cell volume and plasma biochemistry reference intervals and reference values. J Herp Med Surg. 2020;30(3):156–164. doi: 10.5818/19-01-184.1.
5. de la Navarre BJS. Current diagnostic techniques and therapeutic techniques in reptiles and amphibians. Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2015:74.
6. Di Giuseppe M, Morici M, Martinez Silvestre A, Spadola F. Jugular vein venipuncture technique in small lizard species. J Small Anim Pract. 2017;58(4):249. doi: 10.1111/jsap.12656. Epub 2017 Feb 11. PMID: 28188616.
7. Di Giuseppe M, Morici M, Martinez Silvestere A, et al. Jugular vein venipuncture technique in small lizards. Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2017: 572-573.
8. Divers SJ. Diagnostic techniques and sample collection. In: Divers SJ, Stahl SJ (eds). Mader’s Reptile and Amphibian Medicine and Surgery, 3rd ed. St. Louis, MO: Elsevier. 2019:1087-1088.
9. Divers SJ, Camus MS. Lizards. In: Heatley JJ, Russell KE (eds). Exotic Animal Laboratory Diagnosis. Wiley Blackwell. 2020:319-346.
10. Eshar D, Lapid R, Eshar VH. Transilluminated jugular blood sampling in the common chameleon (Chamaeleo chamaeleon). J Herp Med Surg 2018;28(1):19-22. doi: 10.5818/17-10-127.1.
11. Gould A, Molitor L, Rockwell K, Watson M, Mitchell MA. Evaluating the physiologic effects of short duration ultraviolet B radiation exposure in leopard geckos (Eublepharis macularius). J Herp Med Surg. 2018;28(1-2):34–39. doi: 10.5818/17-11-136.1.
12. Hanley CS, Hernandez-Divers SJ, Bush S, Latimer KS. Comparison of the effect of dipotassium ethylenediaminetetraacetic acid and lithium heparin on hematologic values in the green iguana (Iguana iguana). J Zoo Wildl Med. 2004;35(3):328-332.
13. Heatley JJ, Russell KE. Hematolgy. In: Divers SJ, Stahl SJ (eds). Mader’s Reptile and Amphibian Medicine and Surgery, 3rd ed. St. Louis, MO: Elsevier. 2019:865.
14. Laube A, Pendl H, Clauss M, Altherr B, Hatt JM. Plasma biochemistry and hematology reference values of captive panther chameleons (Furcifer pardalis) with special emphasis on seasonality and gender differences. J Zoo Wildl Med. 2016;47(3):743-753. doi: 10.1638/2015-0161.1. PMID: 27691946.
15. Mader DR. Clinical pathology in reptiles: What do these results mean? Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2015:59-60
16. Mayer J, Knoll J, Innis C, Mitchell MA. Characterizing the hematologic and plasma chemistry profiles of captive Chinese water dragons, Physignathus cocincinus. J Herp Med Surg. 2005;15(3):45–52. doi: 10.5818/1529-9651.15.3.45.
17. Mayer J, Knoll J, Wrubel KM, Mitchell MA. Characterizing the hematologic and plasma chemistry profiles of captive crested geckos (Rhacodactylus ciliatus). J Herp Med Surg. 2011; 21(2-3):68-75. doi: 10.5818/1529-9651-21.2.68.
18. Mitchell MA. Reptile biochemistries. Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2013:22-23.
19. Mitchell MA. Managing the reptile patient in the veterinary hospital: Establishing a standard of care model for nontraditional species. J Exotic Pet Med. 2010;19(1):56-72. doi: 10.1053/j.jepm.2010.01.015.
20. Nevarez J. Lizards. In: Mitchell MA, Tully TN (eds). Manual of Exotic Pet Practice. Saunders Elsevier; St. Louis; 2009:179-180.
21. Pendl H. Avian and reptilian haematology. Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2015:177-178.
22. Proença LM. Blood sampling and intravenous access in exotic species. Proc International Conference on Avian Herpetological and Exotic Mammal Medicine 2015:122-126.
23. Sykes JM 4th, Klaphake E. Reptile hematology. Clin Lab Med. 2015;35(3):661-80. doi: 10.1016/j.cll.2015.05.014. PMID: 26297412.
Further reading
Dyer SM, Cervasio EL. An overview of restraint and blood collection techniques in exotic pet practice. Vet Clin North Am Exot Anim Pract. 2008;11(3):423-43, v. doi: 10.1016/j.cvex.2008.03.008. PMID: 18675727.
de la Navarre BJS. Common procedures in reptiles and amphibians. Vet Clin Exot Anim Pract. 2006;9:248. doi: 10.1016/j.cvex.2006.04.002. PMID: 16759946.
O’Malley B. Lizards. In: Clinical Anatomy and Physiology of Exotic Species. St. Louis, MO: Saunders-Elsevier; 2005: 64.
Porter WR, Witmer LM. Vascular patterns in iguanas and other squamates: blood vessels and sites of thermal exchange. PLoS One. 2015;10(10):e0139215. doi: 10.1371/journal.pone.0139215. PMID: 26466378; PMCID: PMC4605690.
Saggese MD. Clinical approach to the anemic reptile. J Exotic Pet Med 2009;18(2):98-111. doi: 10.1053/j.jepm.2009.04.003.
Pollock CG. Blood collection in lizards. LafeberVet web site. April 28, 2022. Available at https://lafeber.com/vet/blood-collection-in-lizards/