Filling time of a lamellar capillary-filling semen analysis chamber is a rapid, precise, and accurate method to assess viscosity of seminal plasma.

SANNE RIJNDERS,* JAN G. M. BOLSCHER,{JOSEPH MCDONNELL,* ANDJAN P. W. VERMEIDEN*{From the *IVF Center, Vrije Universiteit MedicalCenter, Amsterdam, The Netherlands; gametes (Gonzales et al, 1992). Deviant viscosity canDepartment ofOral Biochemistry, Academic Centre Dentistry,Amsterdam, The Netherlands; and`Leja Products BV, Nieuw-Vennep, The Netherlands.Among men from infertile couples, increased viscosityof the ejaculate has been reported to occur morefrequently than in fertile men (Moon and Bunge, 1968;Bunge, 1970). During standard semen analysis, severalsemen variables are evaluated (Oehninger, 2000), butviscosity is rarely quantified. Since the current seminalvariables have limited prognostic value (Castilla et al,2006), extra variables are needed to improve malefertility diagnostics.Viscosity is a semen variable that has received relativelylittle attention in the literature. Hyperviscosity might bedue to dysfunction of accessory sex glands. Associationshave been made between hypofunction of seminal vesiclesand hyperviscosity (Gonzales et al, 1993), and alteredprostate function is associated with low zinc content insperm chromatin and low chromatin stability (Bjo¨rndahland Kvist, 1990). When this integrity is altered, spermquality declines. Seminal viscosity abnormality has beenshown tobe associatedwithmaleinfertility and was foundto accompany poor semen quality (Elzanaty et al, 2004)and altered sperm motility (Eliasson, 1973, Gonzales et al,1993). It also has been shown that the epididymis andaccessory sex glands play a role in the function of maleaffect the quality of sperm cells. Hyperviscosity canattribute to biophysical alterations or chemical changes ofthe ejaculate thatcouldimpact sperm quality despiteothernormal sperm variables seen during semen analysis(Gonzales and Sanchez, 1994). To make viscosity a diagnostic variable, the relation-ship between viscosity and fertility needs to be de-termined. First the viscosity of semen must be quantifiedproperly. Currently this remains a time-consuming jobbecause specialized machinery is required. The methodfor viscosity assessment suggested by the World HealthOrganization (1999) is semiquantitative and in ouropinion, inadequate for good quantitative assessments.A method that can be widely used and that expresses itsresults in centipoise (cP), the international unit ofviscosity, is needed.It is known that the flow velocity in a capillarydepends on the diameter of the capillary, the angle ofcontact, and the viscosity of the fluid. For this study, weused capillary-loaded semen analysis chambers fromLeja. The properties of these chambers are well defined.According to theoretic assumptions, a linear relation-ship exists between filling time of the capillary andviscosity of the sample (Douglas-Hamilton et al, 2005). The aims of this study were to assess the relationshipbetween the filling time of a capillary-loaded chamberand the viscosity of seminal plasma, to express theviscosity in cP, and to assess the accuracy and precision ofthe proposed method. Such a method will make itpossible to describe the relationship between fertility andthe semen variable viscosity. This will extend the numberof variables available for the assessment of male fertilityand will contribute to better models of male fertility.