Protocol - Testes Volume

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A physician uses an orchidometer to measure testes size and determine the onset of puberty and later pubertal development. The orchidometer beads, which are of increasing volume from 1 ml to 25 ml, are compared with the size of the subject’s testicles. The examiner is careful to only include testicular tissue in the comparison.

Specific Instructions

The orchidometer, a series of ellipsoids of increasing volume, are used to determine testes size. Each testis is measured with the patient standing in a warm room. The ellipsoid is held up to each isolated testis and a measurement is estimated, making sure not to include the epididymis in the measurement. One measurement is adequate, but it never hurts to do more than once (Prader, 1966, 1975). The testicular examination requires two hands and should be performed in a warm room. The hands may be lubricated with surgical lubricant or warm, soapy water if necessary. The patient is supine. One hand is placed near the anterior superior iliac spine and the other on the scrotum. The first hand is swept from the anterior iliac spine along the inguinal canal to gently express any retained testicular tissue into the scrotum. A true undescended or ectopic inguinal testis may slide or "pop" under the examiner’s fingers during this maneuver. A low ectopic or retractile testis will be felt by the second hand as the testis is milked into the scrotum by the first hand (Cooper & Docimo, 2010; Drutz, 2010). Examination of older children and adult testes is routinely performed in the standing position. Examination of adults with a suspected undescended testis should be done in both the supine and standing positions with adequate cremasteric relaxation to differentiate true undescended testicle (UDT) or ectopic testes from retractile testes (Eyre, 2010).

Normal testicular length and volume, by age*

Age (year)

Length, cm

(mean ± SD)

Volume, ml (approximate)

< 2

1.4 ± 0.4

2 - 4

1.2 ± 0.2

4 - 6

1.5 ± 0.6


6 - 8

1.8 ± 0.3

8 - 10

2.0 ± 0.5


10 - 12

2.7 ± 0.7


12 - 14

3.4 ± 0.8


14 - 16

4.1 ± 1.0


16 - 18

5.0 ± 0.5


18 - 20

5.0 ± 0.3


*Note: Testicular volume can vary by a factor of two. Adapted from Keefer, J. R. (2000). Endocrinology (p. 227). In G. K. Siberry & R. Iannone (Eds.), Harriet Lane handbook (15th ed.). St. Louis, MO: Mosby.




Editor’s note: The photographs accompanying this protocol have been omitted. Please find these photographs, along with the protocol in Herman-Giddens et al. (2010).

Marcia E. Herman-Giddens; Carlos J. Bourdony; Steven A. Dowshen; and Edward O. Reiter. (2010). Using an Orchidometer. In: Assessment of Sexual Maturity Stages in Girls and Boys. ISBN 13: 978-1-58110-443-1, pp. 35-36.

Using the orchidometer

1. Gently grasp the testicle between the thumb and third finger while holding the beads in the opposite hand. Manipulate the testis to expose it for comparison as shown.*

Opposing the fingertips just behind the testis should result in gentle stretching of the scrotal skin over the anterior surface of the testis, permitting more accurate measurement.

2. Start with a bead that is likely to be smaller than the testicle.

While maintaining the grasp, maneuver to a bead with a higher number to assess for a better match.

3. Further check by comparing with the next larger bead. Then record the number of the largest bead that the testis is at least as large as. If the testis size is between beads, record the number on the smaller bead.

Repeat for the opposite testis. Record right and left separately.

*Editor’s Note: Photographs of the proper procedure for using the orchidometer can be found at the following citation:

Marcia E. Herman-Giddens; Carlos J. Bourdony; Steven A. Dowshen; and Edward O. Reiter. Using an Orchidometer. In: Assessment of Sexual Maturity Stages in Girls and Boys. ISBN 13: 978-1-58110-443-1, pp. 35-36.

Personnel and Training Required

Physician uses the orchidometer to measure stage of puberty. The examiner should be trained by someone familiar with the use of the orchidometer.

Equipment Needs


Requirement CategoryRequired
Major equipment No
Specialized training Yes
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Physical Measurement


Infant, Toddler, Child, Adolescent, Adult, Senior, Pregnancy


Males, aged newborn to end of life

Selection Rationale

This protocol is an extensively used clinical method for assessing testicular size and has been validated in a number of studies. While there are several other methods for testicular measurement in addition to the orchidometer, the most accurate of which is ultrasound, the orchidometer is the most commonly used method.


Chinese, English

Logical Observation Identifiers Names and Codes (LOINC) Testes development proto 62676-2 LOINC
Human Phenotype Ontology Abnormality of the testis size HP:0045058 HPO
Human Phenotype Ontology Puberty and gonadal disorders HP:0008373 HPO
caDSR Form PhenX PX101501 - Testes Development 5971446 caDSR Form
Derived Variables


Process and Review

The Expert Review Panel #5 (ERP 5) reviewed the measures in the Reproductive Health domain.

Guidance from ERP 5 includes:

  • Revised descriptions of the measure

Back-compatible; no changes to the Data Dictionary.

Previous version in Toolkit archive (link).

Protocol Name from Source

Melmed, S., et al. Williams textbook of endocrinology, 2008


Herman-Giddens, M. E., Bourdony, C. J., Dowshen, S. A., & Reiter, E. O. (Eds.). (2010). Using an orchidometer (pp. 35-36). In Assessment of sexual maturity stages in girls and boys. Elk Grove Village IL: American Academy of Pediatrics.

Melmed, S., Polonsky, K., Reed Larsen, P., & Kronenberg, H. M. (Eds.). (2008). Williams textbook of endocrinology (11th ed.). Philadelphia, PA: Saunders.

General References

Cooper, C., & Docimo S. (2010). Undescended testes (cryptorchidism) in children and adolescents. In J. E. Drutz (Ed.), UpToDate. Waltham, MA: Wolters Kluwer.

Drutz, J. E. (2010). Undescended testes (cryptorchidism) in children and adolescents. In T. K. Duryea (Ed.), UpToDate. Waltham, MA: Wolters Kluwer.

Eyre, R. C. (2010). Evaluation of nonacute scrotal pathology in adult men. In M. P. O’Leary (Ed.), UpToDate. Waltham, MA: Wolters Kluwer.

Keefer, J. R. (2000). Endocrinology (p. 227). In G. K. Siberry & R. Iannone (Eds.), Harriet Lane handbook (15th ed.). St. Louis, MO: Mosby.

Prader, A. (1975). Delayed adolescence. Clinical Endocrinology and Metabolism, 4(1), 143-155.

Prader, A. (1966). Testicular size: Assessment and clinical importance. Triangle, 7, 240-243.

Slora, E. J., Bocian, A. B., Herman-Giddens, M. E., Harris, D. L., Pedlow, S. E., Dowshen, S. A., & Wasserman, R. C. (2009). Assessing inter-rater reliability (IRR) of Tanner staging and orchidometer use with boys: A study from PROS. Journal of Pediatric Endocrinology and Metabolism, 22(4), 291-299.

Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX101501020000 Number of the largest bead that is at least more
as large as the left testis show less
PX101501010000 Number of the largest bead that is at least more
as large as the right testis show less
Reproductive Health
Measure Name

Testes Volume

Release Date

February 26, 2010


Testes volume is an indication of testicular function and sexual development. Testicular volume is measured by an orchidometer, which consists of a string of 12 numbered wooden or plastic elipsoid beads of increasing size measured as volume.


Testicular volume increases with the onset of puberty and the initiation of spermatogenesis and can be used to confirm pubertal onset. Small testes (<12 cc) may indicate either primary or secondary hypogonadism and large testes (>30 cc) may indicate other testicular pathology.


Reproductive health, testes development, pubertal development, puberty, orchidometer

Measure Protocols
Protocol ID Protocol Name
101501 Testes Volume

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