The number of mature spermatids seen per seminiferous tubule correlates with the sperm count. If the measured sperm count is much less than that estimated from the spermatid count, then a ductal obstruction is likely.
Procedure:
(1) The testicular biopsy must be performed rapidly and carefully, to minimize distortion or artifact.
(2) Zenker's was used as the fixative.
(3) Mature spermatids are counted, since these are easily and reproducibly measured.
(4) The average number of mature spermatids per tubule is calculated.
|
spermatids per tubule |
sperm count in million per mL |
|
0 |
0 |
|
8 |
2.5 |
|
15 |
5 |
|
17 |
7.5 |
|
19 |
10 |
|
21 |
15 |
|
24 |
20 |
|
26 |
25 |
|
28 |
30 |
|
30 |
35 |
|
32 |
40 |
|
33 |
45 |
|
36 |
50 |
|
37 |
55 |
|
38 |
60 |
|
39 |
65 |
|
41 |
70 |
|
42 |
75 |
|
43 |
80 |
|
44 |
85 |
|
46 |
90 |
|
47 |
95 |
|
48 |
100 |
|
49 |
105 |
|
50 |
110 |
estimated from Figure 7, page 484 (Silber, 1981)
line approximating sperm count for spermatid count of 0 to 19 per tubule =
= (0.0002173 * ((spermatid count) ^ 4)) - (0.005479 * ((spermatid count) ^ 3)) + (0.0429612 * ((spermatid count) ^ 2)) + (0.1978566 * (spermatid count))
line approximating sperm count for spermatid count of 19 to 50 per tubule =
= (0.0008356 * ((spermatid count) ^ 3)) - (0.030603 * ((spermatid count) ^ 2)) + (2.2258284 * (spermatid count)) - 26.73539
Interpretation:
• severe oligospermia is seen with less than 10 million sperm per mL, which correlates with a spermatid count of less than 20 per tubule
• if the measured sperm count approximates the predicted sperm count from the spermatid count, then an obstruction is unlikely
• if the measured sperm count is much less than the predicted, then a ductal obstruction is likely
Specialty: Urology
ICD-10: ,
