Related Experiment Video
Updated: May 10, 2026

Anogenital Distance and Perineal Measurements of the Pelvic Organ Prolapse (POP) Quantification System
Published on: September 20, 2018
Accuracy of Prader orchidometer in measuring testicular volume
T U Mbaeri1, J C Orakwe, A M Nwofor
1Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, Nnewi Anambra State, Nigeria.
Background:
Seminiferous tubules comprise 80-90% of testicular mass. Thus, the testicular volume is believed to be an index of spermatogenesis. Therefore, accurate testicular volume is one way to assess testicular function.
Objective:
To determine the accuracy of Prader orchidometer for measuring the testicular volume by comparing the resultant measurement with the actual testicular volume in humans.
Materials And Methods:
The testicular volumes of 121 testes from 62 patients with prostate cancer (mean age 72.74 ± 9.38 years) were measured using Prader orchidometer before therapeutic bilateral orchidectomy. The actual testicular volumes were then determined by water displacement of the testis.
Results:
The mean testicular volume of the 121 testes was 10.60 ± 3.5 ml and 13.26 ± 5.2 ml for water displacement and Prader orchidometer measurements, respectively. A strong correlation was found between the actual testicular volume and volumes obtained by Prader orchidometer ( r = 0.926, P = 0.0001). The Prader orchidometer however, over-estimated the mean actual testicular volume by 2.66 ± 2.37 ml (25.10%).
Conclusion:
The result of this study has shown that measuring the testicular volume by Prader orchidometer overestimates the actual testicular volume.
Related Concept Videos
Testes: Gross Anatomy
Each testis is surrounded by the tunica albuginea, a dense connective tissue layer that provides structural support and protection. This layer is covered by an outer serous membrane called the tunica vaginalis, which helps reduce friction...
Testing a Claim about Mean: Unknown Population SD
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used; instead...
Testing a Claim about Standard Deviation
The hypothesis testing for the claim of population standard deviation (or variance) requires the data and samples to be random and unbiased. The population distribution also must be normal. There is no specific requirement on the sample size as the estimation is based on the chi-square distribution.
As a first step, the hypothesis (null and alternative) concerning the claim about...
Uncertainty in Measurement: Reading Instruments
Urodynamic Studies: Uroflowmetry
Testes: Histology
The spermatogenic cells, responsible for producing sperm, are...

