University of Birmingham
2016 Laboratory guidelines for postvasectomy
semen analysis: Association of Biomedical
Andrologists, the British Andrology Society and the
British Association of Urological Surgeons
Hancock, Paul; Woodward, Bryan; Muneer, Asif; Kirkman-Brown, Jackson
DOI:
10.1136/jclinpath-2016-203731
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Citation for published version (Harvard):
Hancock, P, Woodward, B, Muneer, A & Kirkman-Brown, J 2016, '2016 Laboratory guidelines for postvasectomy
semen analysis: Association of Biomedical Andrologists, the British Andrology Society and the British
Association of Urological Surgeons', Journal of Clinical Pathology. https://doi.org/10.1136/jclinpath-2016-203731
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2016 Laboratory Guidelines for Post Vasectomy Semen
Analysis - Association of Biomedical Andrologists, the British
Andrology Society, and the British Association of Urological
Surgeons.
P Hancock
1
; BJ Woodward
1,4
; A Muneer
2,3,5
; JC Kirkman-Brown
2,6,7
1
Member of Association of Biomedical Andrologists (ABA) Executive committee
2
Member of British Andrology Society (BAS) Executive committee
3
Chairman British Association of Urological Surgeons (BAUS) Section Andrology
4
IVF Consultancy Services, Leicester, UK
5
Department of Andrology and Urology, University College London Hospitals, London, UK
6
Centre for Human Reproductive Science, Institute of Metabolic & Systems Research (IMSR), College of
Medical & Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
7
Birmingham Women’s Fertility Centre, Birmingham Women’s NHS Foundation Trust, Birmingham, UK.
Abstract
Post vasectomy semen analysis (PVSA) is the procedure used to establish whether sperm are present in the
semen following a vasectomy. PVSA is presently carried out by a wide variety of individuals, ranging from
doctors and nurses in General Practitioner (GP) surgeries to specialist scientists in andrology laboratories, with
highly variable results.
Key recommendations are that: 1) PVSA should take place a minimum of 12 weeks after surgery and after a
minimum of 20 ejaculations; 2) Laboratories should routinely examine samples within 4 hours of production if
assessing for presence of sperm. If non-motile sperm are observed, further samples must be examined within
1 hour of production; 3) Assessment of a single sample is acceptable to confirm vasectomy success if all
recommendations and laboratory methodology are met and no sperm are observed. Clearance can then be
given; 4) The level for special clearance should be <100,000/ml non-motile sperm. Special clearance cannot be
provided if any motile sperm are observed and should only be given after assessment of two samples in full
accordance with methods contained within these guidelines.
Surgeons are responsible both pre-operatively and post-operatively for the counselling of patients and their
partners regarding complications and the possibility of late recanalisation after clearance.
These 2016 guidelines replaces the 2002 British Andrology Society (BAS) laboratory guidelines and should be
regarded as definitive for the UK in the provision of a quality PVSA service, accredited to ISO 15189:2012, as
overseen by the United Kingdom Accreditation Service (UKAS).
KEYWORDS
Guidelines, sterilisation, male, laboratory, protocols, spermatozoa, vasectomy
2016 PVSA Guidelines
2016 PVSA Guidelines
INTRODUCTION
Post vasectomy semen analysis (PVSA) is the laboratory procedure used to establish whether sperm are
present in the semen following a vasectomy. As such, PVSA indicates whether surgery has been successful to
achieve male sterilisation.
PVSA continues to be carried out by a wide variety of individuals with different levels of training. This ranges
from doctors and nurses in GP surgeries to specialist scientists in dedicated andrology laboratories. PVSA may
also be performed in general pathology laboratories. Consequently, the test quality and control of the
procedure is variable, which is clearly not acceptable for a “Yes/No” indicator of surgical success.
In the UK, the move towards laboratory accreditation overseen by the United Kingdom Accreditation Service
(UKAS) to the international standard ISO 15189:2012, is driving the quality of the PVSA process forward. Only
laboratories meeting this analytical standard should be considered as providing the necessary reliability of
result to confirm successful vasectomy.
In 2002 the British Andrology Society (BAS) published a set of laboratory guidelines for PVSA [1]. Advances in
technique options, observations of areas where uncertainty exists and compliance with the ISO 15189:2012
standard, now make additions to the 2002 BAS guidelines desirable. Revisions include clarifying factors around
when and how to test and the number of samples that should be examined.
These 2016 guidelines have been agreed and accepted across the three major groupings and co-author
professional bodies for the field as best practice providing for standardisation of seminal analysis protocols
and reporting of results. Crucially it should be noted that they are not only clinical recommendations but also
take into account good laboratory practice and the accuracy of diagnosis. As such they supercede any prior
guidelines published for the UK. The guidelines do not deal with the counselling of patients or discuss the
indications for male sterilisation, for which compliance with the Faculty of Sexual & Reproductive Healthcare
(FSRH) clinical guidance for male and female sterilization is recommended[2].
It is always important for patients to be warned that a vasectomy may apparently fail at any time, though the
actual chance of this is rare, at less than 1% if correctly performed [3-8], with some reports suggesting that
temporary reappearance of sperm may occur a year after clear PVSA [9].
Failures can be classed into early and late recanalisation. Recanalisation is considered to have occurred where,
after an initial azoospermic sample, there is a rapid increase in sperm numbers [10 11] . These are suggested
to comprise the major category of vasectomy failures [12]. The potential for late recanalisation has been
reported to be around 0.04% to 1% [4 13].
Measurements of vasectomy failure are complex to interpret, as many are only discovered after an adverse
outcome, i.e. occurrence of a pregnancy. It should also be recognized that no data exist relating to women
who may seek pregnancy terminations after this unexpected outcome, perhaps without telling their partner.
As pregnancies have been confirmed to occur even after repeated azoospermic samples, [14] due caution
around the meaning of a PVSA result should always be noted in reports. The patient should be provided with
information from his clinician regarding the likelihood of a successful vasectomy operation and the possibility
of recanalisation. It is recommended that such information should be given both verbally and in writing [12].
FERTILITY OF RESIDUAL SPERM POST SURGERY
Ejaculates may contain potentially fertile sperm immediately after vasectomy [15], and patients should
continue with contraceptive precautions until successful vasectomy has been confirmed. This has been
extensively discussed in the 2002 BAS guidelines [1] and by the FSRH [2].
2016 PVSA Guidelines
POST VASECTOMY SEMEN SAMPLES
Scheduling of sample testing
The time between the vasectomy and the PVSA has been widely discussed without agreement, with some
publications even suggesting a wait of up to 6 months before first analysis [16]. However, the majority of
published literature suggests a minimum number of weeks before testing of between 12 [6 11 16 17], 14 [18
19] and 16 weeks [1 20]. Decreased patient compliance has been noted with longer intervals [6 17 20].
The earlier the PVSA testing occurs, the more the likelihood increases of a false positive result. This may be
due to an inflammatory reaction and/or temporary bruising within the testis. These is also evidence that early
recanalisation can occur within the first few weeks following a vasectomy, and this may be more common
after certain techniques[12] and may be transient [21]. Testing too early may also cause problems with
analysis due to high sample viscosity, presence of residual (usually non-motile) sperm and raised levels of
round cells that may mask sperm presence. Therefore, the desire to perform prematurely early PVSAs has to
be balanced against the increased patient inconvenience and also the workload / cost to the laboratory (e.g.
[16 17 22 23]) as repeat tests would be required for accurate confirmatory diagnosis.
There is a consensus that ‘sufficient ejaculations’ should take place between the vasectomy and the PVSA,
since ejaculatory frequency will affect time to azoospermia. [1 11 24]. Men with fewer than 3 ejaculations per
week have been reported to reach azoospermia around 5 weeks later than those with a higher number of
ejaculations [25]. It has also been reported that azoospermia may not be achieved until 60 ejaculates for some
individuals [25]. However, systematic review data indicates that by 20 ejaculates, 80% of men should show
azoospermia or sperm numbers beneath detectable levels [11] . It is therefore recommended that knowing
the number of ejaculates is important, though some authors have debated this point [24].
The recommendation is Grade B due to robust evidence, noting that it is surprising and disappointing that no
conclusive multi-centre study has yet occurred for such a prevalent procedure.
Recommendation 1: PVSA should take place a minimum of 12 weeks after surgery and after a minimum of
20 ejaculations.
Pre-Assessment
Sample collection instructions
The laboratory staff should ensure that the person requesting the PVSA test is provided with clear ‘user
information’ in the form of written instructions for sample collection. Sample production should be arranged
on an appointment basis to ensure the laboratory has sufficient time for each assessment to be completed
within recommended analytical time frames.
The specimen container
Gamma-irradiated and mouse embryo assay (MEA)-tested specimen containers are recommended for use,
together with CE-marking for containers manufactured in Europe. However, none of these tests confirm the
level of sperm non-toxicity. Specimen containers should therefore additionally be confirmed as non-toxic to
sperm via an in-house sperm toxicity bioassay [26]. Confirmation of sperm non-toxicity should also apply to all
consumables used in the PVSA process that come in to contact with the sample, e.g. any tubes, slides,
coverslips and pipette tips. Traceable sperm toxicity testing is required for each new batch and make of item,
in accordance with ISO 15189:2012.
If samples are provided in unscreened specimen containers, the PVSA report will only be valid if no sperm are
observed. If sperm are observed, and they are immotile, then no confirmation of sperm non-toxicity from the
2016 PVSA Guidelines