To use the Testicular Volume Calculator, enter a width for the testis in centimenters (enter one decimal point from 0 to 9), then select an option for the genital stage development. See instructions.
Calculator
Testicular Volumes – (W-ss)3 X 0.88 by Genital Stages. Equivalent to Ultrasound W x H x L x 0.71
|
Stage |
Age |
# of Testes |
|
Volume (ml) |
||
|
|
Median |
Quartiles - 25-75% |
Range Observed |
|||
|
Stage 1-a* |
3.4 to 6.5 |
24 |
0.71 |
0.50 to 0.71 |
0.50 to 0.71 |
|
|
1-b* |
7.2 to 8.7 |
24 |
0.71 |
0.71 to 0.77 |
0.60 to 0.96 |
|
|
1-c* |
8.9 to 13.2 |
32 |
0.96 |
0.71 to 1.27 |
0.60 to 1.27 |
|
|
Stage 1 All |
3.4 to 13.2 |
80 |
0.71 |
0.71 to 0.96 |
0.50 to 1.27 |
|
|
Stage 2 |
10.0 to 15.0 |
34 |
3.62 |
2.68 to 4.00 |
2.16 to 6.52 |
|
|
Stage 3 |
11.4 to 15.0 |
22 |
6.42 |
5.48 to 6.42 |
4.64 to 7.47 |
|
|
Stage 4 |
11.7 to 16.9 |
44 |
10.85 |
8.27 to 12.32 |
6.13 to 12.32 |
|
|
Stage 5 |
13.0 to 17.5 |
38 |
17.32 |
15.47 to 17.32 |
10.71 to 21.46 |
|
|
Adult |
15.8 to 34.0 |
100 |
17.13 |
15.29 to 21.24 |
10.57 to 21.24 |
|
|
*Stage 1a, b, c: The only criterion for separation is age (Enter the number 1 only in the Genital Stage box). For testicular volumes calculated by W x H x L x 0.52, divide values reported by 1.365 (0.71/0.52 = 1.365). |
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Overview
A Medical Calculator to Determine Testicular Volumes Matching Ultrasound Values
From the Width of the Testis Obtained in the Scrotum with a Centimeter Ruler.
A calculator was developed, requiring only the identification of ① the width of the testis in cm obtained in the scrotum with a ruler (without corrections) (i.e. 0.9, 1.5, 2.0, 2.4 cm etc.) and ② the stage of genital development (G). The calculator will subtract the scrotal skin for the stage of genital development, from the measurement of the width provided, apply the formula and identify the testicular volume of the subject that matches the US volume.
The calculator will also provide, in a Table form, the values for the different stages of genital development.
Instructions
The provider ① measures the width of the testis in the scrotum, by smoothing the scrotal skin around the testis, avoiding compression, and using the ruler (i.e. 0.9, 1.5, 2.0, 2.4 cm etc.), and ② identifies the stages of genital development (1 to 5 or A for adults).
The provider needs to be familiar with the stages of genital development. This may require some explanation to avoid confusion. These are the stages of genital development described by Tanner and not the Tanner stages or pubertal stages, usually used, that include testicular volumes by orchidometer and pubic hair, without mentioning penis.
Tanner in 1969 and Marshall & Tanner, in 1970, reported genital development stages of 3 and 4 in males on Tanner stage 1; that is the reason they recommended to analyze the genital development and pubic hair development independently, because one could be out of step with the other.
The main characteristics of the stages of genital (G) development (testis, scrotum and penis only), independent of pubic hair development, were well defined by Tanner: G1. Prepubertal or preadolescent; the testes and the scrotum are small and penis is as in early childhood. G2. The testes and the scrotum have enlarged and there is some reddening of the scrotal skin. The penis is still as in early childhood. G3. Growth of the penis in both length and breadth and further growth of testes and the scrotum. G4. The penis has further enlarged in length and breadth with development of the glans. The testes and scrotum are further enlarged. G5. Genitalia are adult in size and shape.
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