Patent Description:
Worldwide, <NUM>-<NUM>% of couples that attempt to conceive a new child have sub-optimal fertility. Difficulty in conceiving may be due to defects in either the male or the female reproduction system or a combination of the two, or due to other contributing factors. In approximately <NUM>% of cases of infertility, the male partner is a contributing factor. The primary metrics available to evaluate male fertility are sperm count and motility. Sperm count is a concentration of sperm cells in semen and motility is a percentage of sperm cells capable of movement.

Conventional methods of evaluating male fertility comprise conducting clinical tests including microscopic examination to measure sperm count and motility. Semen samples for the clinical tests must be provided at the site of examination leading to privacy concerns for male subjects. Furthermore, providing a semen sample at the site of examination or in a clinical setting is widely perceived as awkward or embarrassing. This perception can deter male fertility testing for couples with difficulty conceiving despite the high prevalence of male fertility issues. A semen analysis test suitable for use in the home may be useful in cases where aversion to clinical conditions would otherwise deter testing. A few semen analysis test kits have been developed for use in the home, such as those in which a colored line is displayed when the concentration of sperm cells in a sample exceeds a particular number (e.g., <NUM> million per mL) or a color change is displayed when concentration of viable sperm cells in a sample exceeds a particular number (e.g., <NUM> million per mL). In these examples of test kits, the semen analysis tests provide a non-quantitative evaluation of sperm count. In cases where a low sperm count is correctable or sperm count varies over time, it may be desirable to have a quantitative estimate of the absolute sperm count and motility.

European patent application <CIT> discloses a container, adaptable for use with a centrifuge, and comprising a fill well section, a channel section, and a fluid expansion cavity section. The fill well section includes a fill well which receives the fluid sample through an opening in the container. The channel section defines a channel system providing communication between the fill well and the fluid expansion cavities. When the container is spun in a centrifuge, the fluid sample received in the fill well begins to flow through the channel system. The fluid is then collected in a distribution cavity portion of the channel system, which includes a ramped side that restricts the flow of fluid into the fluid expansion cavities. Once the speed of rotation of the centrifuge is increased to a certain level, the centrifugal force imposed on the fluid by the centrifuge forces the fluid to spill over the ramped portion of the distribution cavity and into the plurality of fluid expansion cavities.

The disclosed device and method is for estimation of particulate content in a biological sample, including estimation of cell, such as sperm cell, concentration by centrifugal sedimentation of cells in fluid, such as seminal fluid. The estimation is performed using an enclosed sedimentation column of defined cross-sectional area and by measuring height of a pellet of compacted cells within the sedimentation column with aid of a scale bar along the sedimentation column. In one embodiment, the device includes a cartridge containing the sedimentation column as well as channels and cavities for directing fluid and sedimenting particulates or cells. In other embodiments, the sedimentation column contains fluid of defined density to further separate cell populations by density. The sedimentation column may also include portions of variable cross-sectional area allowing for a visual of the height of sedimented cells in the sedimentation column to resemble measurements of cell concentration in the sedimented cells over a wider range of cell concentrations than otherwise possible. The device also includes or can be used with an instrument for rotating the cartridge at specified rotational rates for intervals of time.

Embodiments of the device can be used at home as home use test kits to estimate sperm cell concentration and motile sperm cell concentration, aiding in diagnosis and monitoring of male fertility disorders and allowing users to avoid having to provide samples in a clinical setting. When used in a fertility context, the device and method allow for a quantitative evaluation of sperm count and motility. The user can get a more accurate estimate of the actual sperm count rather than just determining whether the sperm count is above or below a certain threshold. The user can, for example, determine if sperm count and motility is only somewhat low, and so may be more readily correctable. Similarly, the user can determine if the sperm counts vary over time, possibly allowing the user to identify causative factors for sperm count, and otherwise track times when sperm counts are higher.

The figures depict various embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein.

Various embodiments of estimation of sperm count and motility based on volume occupied by sperm cells packed into a column of defined cross-section following centrifugation is disclosed. The method is similar in principle to the hematocrit technique wherein concentration of red blood cells in a sample volume of blood is estimated by volume of packed red blood cells in a capillary following centrifugation. The hematocrit technique is a well-established technique for estimating red blood cell count in a blood sample based on packed volume of red blood cells following centrifugation from a known sample volume of blood. Estimation of cell count based on packed volume has also been applied to nucleated cell types such as leukocytes and leukocyte sub-types. For example, some hematology analyzers estimate red cell, granulocyte, and lymphocyte cell count from a sample volume of blood centrifuged in a capillary. In many cases, a scalebar incorporated in the hematocrit capillary provides a visual reference and aids in estimation of cell concentration. Thus, packed volume sedimentation provides an easy-to-read method for estimating cell concentration, which can be applied to counting sperm cells.

However, previous implementations used for blood analysis are wholly impractical for direct application to semen analysis. For humans, the average concentration of red blood cells in blood is approximately <NUM> times higher than the average sperm concentration in semen. Also, the considerably higher viscosity of semen prevents uptake of a defined volume of sample by capillary action as is necessary for operation of hematocrit tubes and retards or prevents sedimentation of sperm cells upon centrifugation. Semen is also highly heterogeneous in composition (i.e. initially contains regions of high and low sperm concentration) unlike blood, and therefore requires homogenization to achieve reproducible measurements of concentration. For these reasons, different fluidic structures and modified sample processing steps are necessary to form a sedimented pellet of sperm cells that can be measured. Furthermore, the previously described hematocrit and blood analysis techniques require heavy and expensive centrifuges or dedicated analyzers to spin and contain the sedimentation capillaries, making them impractical for the general public. Nonetheless, if a means of mitigating the considerable challenges listed above was developed, packed volume sedimentation could provide a simple-to-use means of estimating sperm count.

In one embodiment, the estimation of cell count is provided for through use of a device that can be included in a kit. The device comprises a cartridge including a packed volume column and a motorized instrument for spinning the cartridge. The cartridge may attach to the motorized instrument, for example, using a frictional press fit between a motor shaft of the motorized instrument and the cartridge, or using a plurality of magnets. In addition, the device, when prepared as a kit, may also comprise a fluid transfer device and a sample collection cup to assist with transferring the sample to the cartridge. The cartridge may be a disposable cartridge, and a user can use a new cartridge for each sample.

Throughout this description, the disclosed method and device is presented in terms of a method and device for manipulating semen samples for fertility analysis. However, these examples are provided for the purpose of illustration only. The method and device can also be used with other suitable fluids or samples for this method comprising packed volume sedimentation. For instance, the device may also be applied to examining packed volume of particulates in motor oil or to automated quantification of red blood cells or leukocytes in a sample volume of blood. Other types of particulates or solids in other types of samples can also be quantified or otherwise analyzed with the devices and methods described throughout. In some embodiments, the samples are food, soil or other materials, and in other embodiments, the samples are biological samples, such as blood, stool, semen, and other samples that might come from an organism, such as a human.

An embodiment of the device for estimating concentration of cells <NUM> based on volume occupied by cells <NUM> in a packed volume is illustrated in <FIG>. The cells <NUM> are initially suspended in a fluid <NUM>. In one embodiment, the cells <NUM> are sperm cells and the fluid <NUM> is seminal fluid. Following rotation, the cells <NUM> are packed at the bottom of a sedimentation chamber <NUM> and the sedimented cells occupy a volume proportional to a number of cells <NUM> initially suspended in the fluid <NUM>.

A top view and a side cross-section view of an example not according to the claimed invention of a cartridge <NUM> are illustrated in <FIG>, respectively. A top view of the cartridge <NUM> is shown in <FIG> and a cross-sectional side view in <FIG>. The cartridge <NUM> can be constructed from a variety of materials including a polymer or other similar material. All cartridges described throughout the detailed description may be constructed in the same manner. In general, features or materials described for any cartridge included herein can be included or used in any of the other cartridges described herein, as well. Cartridges described herein can be the cartridge <NUM> or embodiments of the cartridge as described per figure.

The cartridge <NUM> may comprise a sedimentation column <NUM> that comprises metering marks <NUM>. The metering marks <NUM> aid a user in determining volume of sedimented cells. The cartridge may also comprise a central sample entry cavity <NUM> and a sample directing cavity <NUM> with a defined volume, the sample directing cavity <NUM> in fluid communication with the central sample entry cavity <NUM>. In other words, the fluid is capable of moving between the central sample entry cavity <NUM> and the sample directing cavity <NUM>. For example, when a volume of fluid equal to the volume of the sample directing cavity <NUM> is added to the central sample entry cavity <NUM> and the cartridge <NUM> is rotated clockwise or counterclockwise about a central axis <NUM> of the cartridge <NUM>, the fluid collects in the sample directing cavity <NUM>. With further rotation, for example at <NUM>-<NUM> RPM for <NUM>-<NUM> minutes, cells from the fluid are packed at the bottom of the sedimentation column <NUM> and the sedimented cells can be read by the user using the metering marks <NUM>. The cartridge <NUM> may additionally include a hub attachment <NUM> configured to securely connect the cartridge <NUM> to a motorized instrument for spinning the cartridge <NUM>. In one embodiment, the cartridge <NUM> may connect or attach to the motorized instrument for spinning the cartridge <NUM> using a plurality of magnets. For all cartridge and instrument descriptions herein, a plurality of magnets can be used to attach the cartridge and the instrument.

In addition, the cartridge <NUM> may hold a reagent pellet <NUM> or be coated with chemical reagents, such as digestive enzymes, to provide fluorescent cell labels, contrast dyes, specific density beads, or, in the embodiment of sperm cells, reduce semen viscosity to facilitate easier reading by the user. These reagents may be freeze dried.

An embodiment of the device as a kit is shown in <FIG>. The device comprises items used for counting cells including a cartridge <NUM> such as a disposable cartridge, a fluid transfer device <NUM> such as a bulb pipette, other type of pipette, or a syringe, a collection cup <NUM> for collecting fluid, and an instrument <NUM> configured to rotate the cartridge <NUM>. The user transfers a defined sample volume into the cartridge <NUM> using the transfer device <NUM>. The transfer device <NUM> may have a level mark configured to assist in measuring the defined sample volume. For the cartridge designs embodied in <FIG>, a non-precise amount of sample may be transferred to the cartridge by the user. The collection cup <NUM> may comprise a reagent pellet <NUM> or be coated with chemical reagents, such as those described above regarding reagent pellet <NUM>, and the reagents or pellets may be freeze dried. Similarly, for all collection cups comprising a reagent pellet herein, the collection cup may comprise the reagent pellet or may be coated with chemical reagents, such as those described above regarding regent pellet <NUM>, and the reagents and/or pellets may be freeze dried. To rotate or spin the cartridge <NUM>, the user can attach the cartridge <NUM> to the instrument <NUM>. In one embodiment, the cartridge <NUM> and instrument <NUM> comprise additional components to securely attach the cartridge <NUM> to the instrument <NUM>.

A top view and a side cross-section view of an embodiment of a cartridge <NUM> are illustrated in <FIG>, respectively. The cartridge <NUM> may comprise a sedimentation column <NUM> that contains metering marks <NUM>. The metering marks <NUM> are configured to aid the user in determining volume of sedimented cells. The cartridge <NUM> also comprises a central sample entry cavity <NUM> and a sample directing cavity <NUM> with a defined volume. The apparatus of the present claims includes a counterbalance cavity. The cartridge <NUM> may also comprise an overflow chamber <NUM> with a counterbalance cavity <NUM> intended to counterbalance the sample directing cavity <NUM>. The overflow chamber <NUM> is connected to the central sample entry cavity <NUM> by shallow channels <NUM>. The shallow channels <NUM> allow the sample in the cartridge <NUM> to move from the central sample entry cavity <NUM> to the overflow chamber <NUM> during rotation, for example during a second round of rotation, as further described in <FIG>. The sample directing cavity <NUM> is connected to the central sample entry cavity <NUM> by additional shallow channels <NUM>. The additional shallow channels <NUM> in one embodiment include a larger depth or diameter than the depth or diameter, respectively, of the shallow channels <NUM>. The shallow channels <NUM> allow the sample to move from the central sample entry cavity <NUM> to the sample directing cavity <NUM>, for example during a first round of rotation, further described in <FIG>. The shallow channels <NUM> and additional shallow channels <NUM> have a depth or diameter configured such that fluid wetting and surface tension forces prevent movement of the sample through the channels <NUM> and <NUM> unless a threshold rotation rate is exceeded by the cartridge <NUM>, for example, during centrifugation. The threshold rotation rate necessary for causing movement of the sample through shallow channels <NUM> is based at least in part on diameter or depth of the shallow channels. For example, the threshold rotation rate will increase as diameter or depth of shallow channels decrease. The cartridge <NUM> may additionally include a hub attachment <NUM> configured to securely connect the cartridge <NUM> to a motorized instrument for spinning the cartridge <NUM> during, for example, centrifugation. The cartridge <NUM> may hold a reagent pellet <NUM> or be coated with chemical reagents, as described above regarding the reagent pellet <NUM>.

An initial state, first rotation rate state and second rotation rate state of an embodiment of fluid movement within a cartridge <NUM> are described in <FIG>, respectively. Fluid <NUM> is initially loaded into a central sample entry cavity <NUM>. In the initial state, the shaded portion of the cartridge <NUM> represents the fluid <NUM>. Upon rotation at a first rotation rate, for example in a range of <NUM>-<NUM> RPM, preferably in a range of <NUM>-<NUM> RPM, the fluid enters a sample directing cavity <NUM> with a defined volume during a first time period until the sample directing cavity <NUM> is full as seen in the rotation rate <NUM> state. The overflow chamber <NUM> may comprise a counterbalance cavity <NUM>. The cartridge <NUM> comprises a sedimentation column <NUM>.

As seen in the rotation rate <NUM> state, since the cross-sectional area of shallow connecting channels <NUM> is smaller than the cross-sectional area of an overflow chamber <NUM>, the fluid <NUM> is prevented from entering the overflow chamber <NUM> during the first rotation rate. Balance of fluid surface tension and wetting forces overcoming effective gravitational force prevents entry of the fluid <NUM> into the overflow chamber <NUM>. In addition, the counterbalance cavity <NUM> assists in counterbalancing the sample directing cavity <NUM>, which fluid <NUM> can also enter during the first rotation rate. Upon rotation of the cartridge <NUM> at a second rotation rate (e.g. <NUM>-<NUM> RPM, <NUM>-<NUM> minutes) during a second time period, the fluid remaining in the central sample entry cavity <NUM> enters the overflow chamber <NUM> and counterbalance cavity <NUM>, as shown in the rotation rate <NUM> state. With centrifugation for the second time period at the second rotation rate, cells in the sample directing cavity <NUM> become compacted in the sedimentation column <NUM>. Then, the pellet of sedimented and compacted cells can be read by the user with a cell pellet height proportional to amount of cells initially contained in the sample directing cavity <NUM> and sedimentation column <NUM> during rotation rate <NUM> state. Due to excess fluid being directed to the overflow channels <NUM> during the second time period, cells can be measured from a precise amount of fluid. In some embodiments, additional rotations can be performed for additional time periods. This can be true for any embodiments described herein. In further embodiments, only a single rotation is performed for an interval of time, and, in some cases, this single rotation provides compacting of the cells. This can be true for any embodiments described herein.

A top view and a side cross-section view of another embodiment of a cartridge <NUM> are illustrated in <FIG>, respectively. The cartridge <NUM> may comprise a sedimentation column <NUM> that contains metering marks <NUM>. The metering marks <NUM> are configured to aid the user in determining volume of sedimented cells. The cartridge <NUM> also comprises a central sample entry cavity <NUM> and a sample directing cavity <NUM> with a defined volume. The apparatus of the present claims includes a counterbalance cavity. The cartridge <NUM> may also comprise an overflow chamber <NUM> with a counterbalance cavity <NUM> intended to counterbalance the sample directing cavity <NUM>. The overflow chamber <NUM> is connected to the central sample entry cavity <NUM> by shallow connecting channels <NUM>. Unlike the sample directing cavity <NUM> being connected to the central sample entry cavity <NUM> by shallow channels such as the shallow channels <NUM> in <FIG>, the sample directing cavity <NUM> can be in direct fluid communication with the central sample entry cavity <NUM>. The sample directing cavity <NUM> and the central sample entry cavity <NUM> are connected in a manner similar to that illustrated in <FIG>. The cartridge <NUM> may also comprise a hub attachment <NUM> configured to securely connect the cartridge <NUM> to a motorized instrument for spinning during centrifugation. The cartridge <NUM> may comprise a reagent pellet <NUM> or be coated with chemical reagents, as described above regarding the reagent pellet <NUM>.

An initial rotation state and a first rotation rate state of an embodiment of the fluid movement within a cartridge <NUM> are described in <FIG>. Fluid <NUM> is initially loaded into a central sample entry cavity <NUM>, as shown in the initial state. The cartridge is intended to be rotated at a first rotation rate (e.g. <NUM>-<NUM> RPM) for a time interval (e.g. <NUM>-<NUM> minutes) and distribute fluid in one step, allowing a simplified instrument design. Upon rotation at the single rate, fluid enters a sample directing cavity <NUM> and a sedimentation column <NUM>, the sample directing cavity <NUM> and the sedimentation column <NUM> comprising a defined volume and being in direct fluid communication with the central sample entry cavity <NUM>, unlike in <FIG> and <FIG> where the sample directing cavity and central sample entry cavity are connected by channels. As the rotation rate of the cartridge <NUM> accelerates and reaches the first rotation rate, a rate necessary to overcome surface tension and wetting forces in shallow channels <NUM> connecting the central sample entry cavity <NUM> and an overflow chamber <NUM> is exceeded, and the fluid remaining in the central sample entry cavity <NUM> will enter the overflow chamber <NUM> and a counterbalance cavity <NUM>, as illustrated in the rightmost illustration of <FIG>. Therefore the fluid remaining in the sample directing cavity <NUM> is the only fluid that contributes to the volume of sedimented cells in the sedimentation column <NUM> following centrifugation. With continued centrifugation (e.g., <NUM>-<NUM> minutes), cells within the sample directing cavity <NUM> become compacted in the sedimentation column <NUM> where a sedimented cell pellet can be read by the user with a pellet height proportional to amount of cells initially contained in the fluid inside the sample directing cavity <NUM> and sedimentation column <NUM> during the rotation <NUM> state.

A top view and a side cross-section view of another embodiment of a cartridge <NUM> are illustrated in <FIG>, respectively. The cartridge <NUM> may comprise a sedimentation column <NUM> that comprises metering marks <NUM>. The metering marks <NUM> are configured to aid the user in determining volume of sedimented cells. The cartridge <NUM> also comprises a central sample entry cavity <NUM> and a sample directing cavity <NUM>. The cartridge <NUM> also comprises a counterbalance cavity <NUM> for counterbalancing the sample directing cavity <NUM>. The sample directing cavity <NUM> is connected to the central sample entry cavity <NUM> by angled shallow channels <NUM>, wherein the angled shallow channels <NUM> comprise an extension <NUM> for retaining or storing sedimented cells. For example, the angled shallow channels <NUM> are angled radially outward from the center of the cartridge <NUM> with respect to the sedimentation column <NUM>. While the sedimentation column <NUM> is located radially outward from the center of the cartridge <NUM> along a first radial axis, the angled shallow channels <NUM> are also located radially outward from the center of the cartridge <NUM> along a second radial axis and a third radial axis, where the second radial axis and the third radial axis are not the first radial axis. The cartridge <NUM> may additionally include a hub attachment <NUM> configured to securely connect the cartridge <NUM> to a motorized instrument for spinning the cartridge <NUM> during, for example, centrifugation. The cartridge <NUM> may comprise one or more reagent pellets <NUM> or be coated with chemical reagents, as described above regarding the reagent pellet <NUM>.

An initial state, first rotation state, second rotation state, and final state of an embodiment of a fluid movement within a cartridge <NUM> are described in <FIG>. Fluid <NUM> is loaded into a central sample entry cavity <NUM>, as seen in the initial state. Upon rotation, fluid travels from central sample entry cavity <NUM> into channel extensions <NUM>, connecting channels <NUM>, and into a sample directing cavity <NUM> with a defined volume. The first rotation rate state is shown in the rotation rate <NUM> state. When rotation rate of the cartridge exceeds a rate necessary to overcome surface tension, the fluid remaining in the central sample entry cavity <NUM> enters a counterbalance chamber <NUM>. The second rotation rate state is shown in the rotation rate <NUM> state. With further rotation of the cartridge <NUM>, for example at <NUM>-<NUM> RPM for <NUM>-<NUM> minutes, cells within the directing cavity <NUM> become compacted in a sedimentation column <NUM> where the sedimented pellet can be read by the user with a pellet height proportional to amount of cells contained in the sample directing cavity <NUM> and sedimentation column <NUM> during the rotation rate <NUM> state. The final state is shown in the final state. Cells initially contained in channel extensions <NUM><NUM> and central sample entry cavity during rotation rate <NUM> state are trapped in channel extensions <NUM><NUM> and therefore do not contribute to volume of sedimented cells in the sedimentation column <NUM>. Locations where compacted cells will collect in the shown cartridge design of <FIG> are marked as <NUM>. An advantage of the design of the cartridge <NUM> is that less material and less complexity is required for manufacturing the cartridge <NUM> than previously described cartridge designs due to lack of overflow chambers. Measurement of volume of cells from only a volume of interest of fluid can be achieved by capturing sedimented cells from excess fluid in an alternate location from the sedimentation column <NUM> rather than physically removing excess fluid from the central sample entry cavity.

<FIG> demonstrates a kit for cell, sperm cell or other particle measurement including a cartridge <NUM>, the cartridge <NUM> an alternative embodiment of the cartridge described in <FIG> (though cartridges of the other Figures can be used too). The sample inlet cavity <NUM> is increased in size to accommodate a fluid <NUM> in its entirety. In one embodiment, the fluid is seminal fluid and the cavity comprises a volume that exceeds a maximum fluid volume produced by a human male, where the maximum fluid volume is about <NUM> milliliters. This design is configured to directly collect a fluid for analysis by the central cavity <NUM>. Optionally, the fluid may be collected in a collection cup <NUM>. The collection cup <NUM> may comprise a spout <NUM> for pouring the fluid into the sample inlet cavity <NUM> of the cartridge <NUM>. Upon centrifugation, such as at <NUM>-<NUM> RPM for <NUM>-<NUM> minutes, cells within a sample directing cavity <NUM> become compacted in a sedimentation column <NUM> while cells in the fluid remaining in the sample inlet cavity <NUM> are retained therein. Either the sample inlet cavity <NUM> or the collection cup <NUM> may contain chemical reagents for enzymatic digestion, contrast enhancement, or other assay enhancing functions. A lid <NUM> that is configured to attach to the cartridge <NUM> during centrifugation to prevent fluid spillage may be included in the kit. The design of <FIG> or the design of <FIG> may comprise sufficiently large overflow cavities, allowing for analysis of a greater volume of fluid, such as up to <NUM> milliliters.

<FIG> is a flowchart of an embodiment of a method for estimating sperm count based on volume occupied by sperm cells packed into a column of defined cross-section following centrifugation. Different embodiments may perform the steps in the method in a different order, omit certain steps, and/or perform additional steps. In one embodiment, the method is performed using a kit comprising a collection cup, a cartridge, a transfer device and an instrument. Any cartridge or instrument design described herein may be used in the method.

The user collects <NUM> a sample or fluid in the collection cup. In one embodiment, the collection cup comprises digestive enzymes such as chymotrypsin, trypsin, bromelain, or papain for accelerating liquefaction of the fluid. The fluid is swirled or agitated <NUM>, for example by the user, in the collection cup (or the sample can be otherwise agitated, such as agitated by the instrument once it is placed in the instrument). Swirling or agitating the fluid accelerates dissolution of the enzyme into the fluid. An interval of time (e.g., of <NUM>-<NUM> minutes) elapses to allow the enzyme to liquefy the fluid. A portion of the fluid is then transferred <NUM> to the cartridge using a transfer device, such as a syringe or bulb transfer pipette. In one embodiment, the cartridge is capped with a lid or sticker following input of the fluid. The cartridge is attached <NUM> to the instrument, wherein the instrument comprises a motor configured to rotate the cartridge. Optionally, the instrument may accelerate the cartridge in one direction and then an opposite direction for an interval of time, mechanically agitating the fluid, encouraging homogenization and reduced viscosity for more consistent measurements. The instrument may also accelerate the cartridge in one direction, allow it to come to a stop, then repeat for an interval of time to provide mechanical agitation. The instrument spins <NUM> or rotates the cartridge at a rotation rate (e.g., for <NUM>-<NUM> minutes at <NUM>-<NUM> RPM). Optionally, the cartridge is spun at a reduced rotation rate for an interval of time (e.g., for <NUM>-<NUM> minutes) to allow for controlled expansion of compacted cells in a sedimentation column of the cartridge. After rotation, the cartridge is halted by the instrument and the user reads <NUM> the result by estimating cell count or concentration in the fluid based on height of compacted cell pellet in the sedimentation column of the cartridge. In some embodiments, the instrument comprises a digital reading the user can read (e.g., digital reading on a user interface of the instrument). All embodiments of the instrument described herein may comprise a digital reading on a user interface of the instrument. In one embodiment, the instrument comprises a lid, wherein the lid comprises one or more magnets and the instrument comprises one or more sensors configured to detect magnetic fields. The one or more magnets and one or more sensors are placed within the lid and the instrument such that, when the lid is closed on the instrument, the one or more magnets in the lid and the one or more sensors in the instrument are a distance away, where the distance is less than a threshold distance necessary for the one or more sensors to detect a magnetic field of the one or more magnets in the lid and thus detect that the lid is closed on the instrument. In another embodiment, the one or more magnets can be in the instrument and the one or more sensors in the lid of the instrument. The magnet and sensor configuration described here can be applied to any instrument described herein.

<FIG> is a flowchart of an embodiment of a method for estimating sperm concentration based on volume occupied by sperm cells packed into a column of defined cross-section following centrifugation. Different embodiments may perform the steps in the method in a different order, omit certain steps, and/or perform additional steps. In one embodiment, the method is performed using a kit comprising a collection cup, a cartridge, a transfer device and an instrument. Any cartridge or instrument design described herein may be used in the method.

The fluid or sample is collected <NUM> by a user in the collection cup. The user may swirl or agitate the fluid to aid in homogenization. A portion of the fluid is then transferred <NUM> to the cartridge using the transfer device immediately or before coagulation of the fluid. The transfer device may be a syringe or bulb transfer pipette. The cartridge may optionally comprise a lid or sticker configured to securely cap the cartridge following input of the fluid in the cartridge. The cartridge is attached <NUM> to the instrument. The instrument comprises a motor and the motor is configured to rotate, spin, or reciprocate <NUM> the cartridge for an interval of time to liquefy the fluid. The instrument may alternately accelerate the cartridge in one direction and then the other for an interval of time to mechanically agitate the fluid, encouraging homogenization and reduced viscosity of the fluid for more consistent measurements. Enzymes enclosed in the cartridge can act on the agitated fluid (e.g., for <NUM>-<NUM> minutes) to promote liquefaction of the fluid. The cartridge is spun <NUM> by the instrument for an interval of time at a specified rate (e.g., for <NUM>-<NUM> minutes at <NUM>-<NUM> RPM). Optionally, the cartridge may then be spun <NUM> at a reduced RPM (e.g., for <NUM>-<NUM> minutes) to allow for controlled expansion of compacted cells in the sedimentation column. After this spin is done, the cartridge is halted by the instrument and the user may read <NUM> a result of an estimate of the cell concentration in the fluid from the height of a compacted cell pellet in the sedimentation column.

<FIG> is a flowchart of an embodiment of a method for estimating sperm concentration based on volume occupied by sperm cells packed into a column of defined cross-section following centrifugation. Different embodiments may perform the steps in the method in a different order, omit certain steps, and/or perform additional steps. In one embodiment, the method is performed using a kit comprising a collection cup, a cartridge, and an instrument. Any cartridge or instrument design described herein may be used in the method.

The fluid or sample is collected <NUM> in the cartridge or collected <NUM> in the collection cup. In the case the sample is collected <NUM> in the collection cup, the entire fluid is poured <NUM> into the cartridge. The cartridge may optionally comprise a lid configured to securely cap the cartridge following input of the fluid in the cartridge. The cartridge is attached <NUM> to the instrument. The instrument comprises a motor and the motor is configured to rotate, spin or reciprocate <NUM> the cartridge. The instrument may alternately accelerate the cartridge in one direction and then the other for an interval of time to mechanically agitate the fluid, encouraging homogenization and reduced viscosity of the fluid for more consistent measurements. Enzymes enclosed in the cartridge can act on the agitated fluid (e.g., for <NUM>-<NUM> minutes) to promote liquefaction of the fluid. The cartridge is spun <NUM> for an interval of time at a specified rate (e.g., for <NUM>-<NUM> minutes at <NUM>-<NUM> RPM). Optionally, the cartridge may then be spun <NUM> at a reduced RPM (e.g., <NUM>-<NUM> RPM for <NUM>-<NUM> minutes) to allow for controlled expansion of compacted cells in the sedimentation column. After this spin is done, the cartridge is halted by the instrument and the user may read <NUM> a result of an estimate of the cell concentration in the fluid from the height of compacted cells in the sedimentation column.

For each of the methods described in <FIG>, the user may perform all of the steps himself at home using a cartridge and/or kit as described throughout this description and using an instrument for rotating the cartridge, such as those described herein. In other embodiments, the user provides the sample in the cartridge, but then the cartridge is delivered to a clinic, such as a fertility center, that performs the rotation/centrifugation of the sample using an instrument at the clinic, such as those described herein. In this case, the user performs the collection <NUM>, <NUM>, <NUM>, <NUM> steps and possibly other steps, such as the swirl/incubate <NUM>, transfer <NUM>, <NUM>, and pour <NUM> steps, but the clinic may perform the attachment <NUM>, <NUM>, <NUM> of the cartridge to the instrument along with the steps that follow. In another embodiment, the user provides the sample in a holding device and it is transferred to the cartridge at the clinic. In this case, the clinic performs the transfers and pour and possibly the swirl/incubate steps. Thus, the method can include just the subset of steps performed by the user or the subset of steps performed by the clinic.

<FIG> describe various embodiments of configurations of the sedimentation column. Any of the described various embodiments may be incorporated into the cartridge designs described in <FIG>.

<FIG> shows an enlargement of a top view and a side view of a sedimentation column, the sedimentation column comprising metering marks <NUM> and numbers <NUM>. After cells are compacted by centrifugation, the height of a resulting pellet <NUM> may be determined visually by differences in reflectance between cells in the pellet <NUM> and fluid <NUM> or by other means including fluorescent cell labels. The user can estimate initial concentration of cells in the fluid by reading the number <NUM> closest to a metering mark <NUM> closest to the interface between the cells <NUM> and the fluid <NUM>.

<FIG> shows an enlargement of a top view and a side view of a sedimentation column, the sedimentation column comprising metering marks <NUM> and numbers <NUM>. The sedimentation column comprises a lens <NUM> configured to magnify the sedimentation column and size of the sedimentation column. The lens <NUM> can be integrated into the sedimentation column during fabrication, for example, by injection molding of polymer. The presence of the lens <NUM> may allow the user to visualize an interface between a pellet <NUM> and fluid <NUM> more easily. In one embodiment, the lens <NUM> is cylindrical in shape. Other types and shapes of lenses can also be used. After cells are compacted by centrifugation, the height of the pellet <NUM> may be determined visually by differences in reflectance between the cells and fluid <NUM> or by other means including fluorescent cell labels. The user can estimate the initial concentration of cells in the fluid by reading the number <NUM> closest to a metering mark <NUM> closest to the interface between the cells <NUM> and the fluid <NUM>.

<FIG> shows a side view of an alternate embodiment of a sedimentation column intended for use with fluorescent analysis. A top lens <NUM> and a bottom lens <NUM> are integrated into a top surface and a bottom surface of the sedimentation column, respectively. In one embodiment, the lenses are cylindrical in shape. Other types and shapes of lenses can also be used. A fluorescent excitation light source <NUM>, such as an LED, filtered lamp, or laser, emits light such that it is focused on the sedimentation column by the bottom lens <NUM>. Labeled cells in a pellet <NUM> are excited by the impinging light and emit a light <NUM> of a wavelength longer than a threshold wavelength. The light <NUM> is focused by the top lens <NUM> onto a detector <NUM>. The detector <NUM> may be a CCD camera, photodiode, photomultiplier, or human eye. A selective filter <NUM> may be placed between the detector <NUM> and the sedimentation column to selectively pass the wavelengths of the light <NUM> emitted by the excited cells. The detector <NUM> may determine the height of the pellet <NUM> by scanning along the sedimentation column and can be based on total fluorescent signal.

<FIG> shows an alternate embodiment of a sedimentation column <NUM> intended for use with fluorescent analysis. Geometry of the sedimentation column <NUM> causes cells to be compacted into a pellet <NUM> with small surface area following centrifugation. A top lens <NUM> and a bottom lens <NUM> are integrated into a top surface and a bottom surface of the sedimentation column, respectively. The top lens <NUM> and the bottom lens <NUM> may be spherical or aspheric lenses. A fluorescent excitation light source <NUM>, such as an LED, filtered lamp, or laser emits light such that the light is focused on the pellet <NUM> by the bottom lens <NUM>. Cells in the pellet <NUM> may be labeled with fluorescent dyes, such as acrinidine orange which are active only within nucleic acid containing cells. Labeled cells in the pellet <NUM> are excited by the impinging light and emit light <NUM> of a wavelength longer than a threshold wavelength. The light <NUM> is focused by the top lens <NUM> onto a detector <NUM> which may be a CCD camera, CMOS sensor, photodiode, photomultiplier, or human eye. A selective filter <NUM> may be placed between the detector <NUM> and the sedimentation column <NUM> to selectively pass the light <NUM> emitted by the excited cells <NUM>. The detector <NUM> may determine a total number of cells present based on total integrated fluorescence emitted by the cells in the pellet <NUM>.

<FIG> shows an alternate embodiment of a sedimentation column intended for use in estimating a wide range of cell concentrations. The sedimentation column comprises metering marks <NUM> and numbers <NUM>. After cells are compacted by centrifugation, height of a resulting pellet <NUM> may be determined visually by differences in light scattering and reflectance between the cells in the pellet <NUM> and fluid <NUM> or by other means including fluorescent cell labels. The user can estimate initial concentration of cells in the fluid by reading the number <NUM> closest to a metering mark <NUM> closest to an interface between the cells in the pellet <NUM> and the fluid <NUM>. In this embodiment, the sedimentation column is tapered comprising a section of a high cross-sectional area <NUM> exceeding a reference cross-sectional area and a low cross-sectional area <NUM> not exceeding a reference cross-sectional area with a transition area <NUM> in between the sections <NUM> and <NUM>. In this embodiment, a pellet comprising low cell concentration will be accommodated by a portion comprising low cross-sectional area <NUM>, while a pellet comprising substantially higher cell concentrations will be accommodated by a portion comprising high cross-sectional area <NUM>. The metering marks <NUM> and numbers <NUM> are adjusted for the different cross-sectional areas, allowing a user to accurately estimate cell concentration. To one skilled in the art, it is apparent that many variations of sedimentation column taper are possible. For instance more than one transition area <NUM> may be integrated into the sedimentation column to create multiple sections with varying cross-sectional area. For example, the multiple sections may comprise sections with sequentially increasing or decreasing cross-sectional areas. In another example, cross-sectional area may continuously increase or decrease along the sedimentation column to accommodate a wide range of cell concentrations and metering marks <NUM> and numbers <NUM> can be adjusted accordingly. The multiple sections may also comprise varying cross-sectional areas such that a visual of the height of the pellet <NUM> in the sedimentation column corresponds to cell concentration of the pellet <NUM>. For example, if a user sees a pellet <NUM> with a height of <NUM>, there are <NUM> metering marks <NUM>, each metering mark equidistant from each other along the pellet <NUM>. In addition, there may be the numbers <NUM> per metering mark. In an embodiment where the visual of the height does not correspond to cell concentration of the pellet <NUM>, there may be <NUM> metering marks <NUM> not equidistant from each other along the pellet <NUM>.

<FIG> shows an embodiment of a sedimentation column <NUM> enclosed by an upper layer <NUM> of polymer and a lower layer <NUM> of polymer. The upper layer <NUM> and lower layer <NUM> may be joined by processes including ultrasonic welding, laser welding, or thermal bonding. A fluorescent excitation light source <NUM>, such as an LED, filtered lamp, or laser, emits light such that the light impinges a pellet <NUM> in the sedimentation column <NUM>. The lower layer <NUM> may be dyed with filtering agents configured to selectively pass light emitted by the light source <NUM> to enhance contrast. Cells in the pellet <NUM> may be labeled with fluorescent dyes, such as acrinidine orange which are active only within nucleic acid containing cells. Labeled cells in the pellet <NUM> are excited by the impinging light and emit light <NUM> of a wavelength longer than a threshold wavelength. The light <NUM> impinges onto a detector <NUM>. Embodiments of the detector <NUM> comprise a CCD camera, photodiode, photomultiplier, or human eye. The upper layer <NUM> may be dyed with filtering agents configured to selectively pass light <NUM> longer than a threshold wavelength emitted by the cells in the pellet <NUM> to improve accuracy of cell detection. The detector <NUM> may determine estimated cell concentration by scanning along the sedimentation column and can be based on total fluorescent signal. The embodiment of the sedimentation column <NUM> described here using dyes with filtering agents may be combined with lenses as described in <FIG> to enhance accuracy of cell count estimations. The features described with respect to the sedimentation column <NUM> may also be used to enhance detection in particle-based immunoassays. The features described with respect to the sedimentation column <NUM> may also be incorporated into the sedimentation column <NUM> of <FIG>.

<FIG> shows an embodiment of a sedimentation column <NUM> enclosed by an upper layer <NUM> of polymer and a lower layer <NUM> of polymer. The upper layer <NUM> and the lower layer <NUM> may be joined by processes including ultrasonic welding or thermal bonding. A light source <NUM>, such as an LED, sunlight, or room lighting, emits light that impinges a pellet <NUM> through the upper layer <NUM>, wherein the polymer of the upper layer <NUM> is transparent. The pellet <NUM> scatters light <NUM> back towards the light source <NUM> due to the pellet's particulate nature while fluid <NUM> transmits light. If the lower layer <NUM> is doped or covered with light absorbing material, such as carbon black or other light absorbing pigments, part of the light transmitted by the fluid <NUM> will be absorbed, enhancing optical contrast between the pellet <NUM> and the fluid <NUM>. The scattered light <NUM> may be detected by a detector, such as a CCD camera, mobile communication device, or human eye, to estimate cell concentration. In this embodiment, the light source <NUM> is perpendicular to the upper layer <NUM>. The light source <NUM> may also be placed in parallel with or in the upper layer <NUM> and still scatter light <NUM> toward a viewer or detector. This configuration may further increase optical contrast of the pellet <NUM> by avoiding or minimizing interfering reflection off of planar surfaces of the layers <NUM> and <NUM>.

<FIG> illustrates an example of a sedimentation column of a fluid following centrifugation, wherein the fluid comprises particles or materials with a density higher than the fluid's density but lower than density of certain cells or particulates in the fluid. The sedimentation column comprises metering marks <NUM> and numbers <NUM>. Following centrifugation, the intermediate density particles or materials form an intermediate layer <NUM> between the pellet <NUM> of compacted cells and the fluid <NUM>. The intermediate layer <NUM> may comprise distinctively colored particles or materials such as dyed polystyrene or another polymer in order to enhance optical contrast of an interface between the pellet <NUM>, intermediate layer <NUM>, and fluid <NUM>. The user can estimate initial concentration of cells in the sample by reading a number <NUM> closest to a metering mark <NUM> closest to an interface between the pellet <NUM> and the intermediate layer <NUM>.

<FIG> alternately may represent an example of the sedimentation column of a fluid following centrifugation, wherein the fluid was mixed with a dye prior to centrifugation that identifies dead cells. For example, the dye can selectively partition into dead cells but not living cells. It is known in the art that dead or immotile sperm cells have a density lower than the density of living and motile sperm cells. The sedimentation column comprises metering marks <NUM> and numbers <NUM>. Following centrifugation, the fluid separates into layers with a fluid layer <NUM> closest to the center of the centrifugation, a live cells layer or a pellet <NUM> furthest from the center of the centrifugation, and a dead cells layer <NUM> with intermediate density in between the two layers <NUM> and <NUM>. Living cells exclude the dye and therefore are visually distinct from the dead cells layer <NUM> and fluid layer <NUM> which also exhibit the color of the dye. The user can estimate initial concentration of living cells in the fluid by reading a number <NUM> closest to a metering mark <NUM> closest to an interface between the pellet <NUM> and the dead cells layer <NUM>. The user can also estimate number of dead cells from the visually distinct dead cell layer <NUM>. As described previously, an intermediate density layer formed from polymer fragments or particles may be mixed into the fluid prior to centrifugation to enhance the contrast between the dead cells layer <NUM> and pellet <NUM>.

<FIG> illustrate various embodiments of mechanisms for attaching a cartridge to a motor of an instrument. These embodiments may be used with any of the cartridges or instruments described herein, or may be used to attach the cartridge to other instruments outside of those described herein. In any embodiment, the cartridge, the motor shaft or an adaptor configured to attach to the motor may comprise a magnetic material, providing a mechanism for attaching the cartridge to the motor.

<FIG> shows an embodiment of a schematic for attaching a cartridge <NUM> to a motor <NUM> of an instrument. The cartridge comprises a cavity <NUM>. The cavity <NUM> comprises a first diameter less than a second diameter of a shaft <NUM> of the motor <NUM>. To attach the cartridge <NUM> to the motor <NUM>, the shaft <NUM> is press-fit into the cavity <NUM>. Material used in the first diameter of the cavity <NUM> and elastic modulus of material used for the cartridge <NUM> may be selected such that a tight friction fit is established between the shaft <NUM> and cavity <NUM> of the cartridge <NUM> allowing rotation of the cartridge <NUM> when attached to the instrument.

<FIG> shows a second embodiment of a schematic for attaching a cartridge <NUM> to a motor <NUM> of an instrument <NUM>. The cartridge comprises a cavity <NUM>. The cavity <NUM> comprises a shape and the adaptor <NUM> comprises the same shape and is configured to fit in the cavity <NUM>. The adaptor <NUM> is attached to the motor <NUM>. To attach the cartridge to the motor, the adaptor <NUM> is press-fit into the cavity <NUM>. Material used in the first diameter of the cavity <NUM> and elastic modulus of material used for the cartridge <NUM> may be selected such that a tight friction fit is established between the motor <NUM> and cavity <NUM> of the cartridge <NUM> allowing rotation of the cartridge <NUM> when attached to the instrument. The material of the adaptor <NUM> may comprise notches configured to allow the adaptor to flex creating a secure fit between the cartridge and adaptor. In another embodiment, the motor <NUM> may comprise a cavity-containing socket and the cartridge <NUM> may comprise a corresponding projection. Additional projections may be added to the adaptor <NUM> of the motor <NUM> in order to create a "snap" fit with the cartridge.

<FIG> show various embodiments of instruments. These embodiments may be used with any of the cartridges described throughout and any of the attachment mechanisms described throughout. In addition, the cartridges can be attached to other instruments outside of those described here.

<FIG> shows an embodiment of a schematic of an instrument configured to rotate a cartridge <NUM>. This embodiment may be used with any of the cartridges described throughout. The instrument comprises an enclosure <NUM>, a printed circuit board <NUM>, a motor <NUM>, a lid <NUM>, a switch <NUM>, indicator LEDs <NUM>, or any combination thereof. In alternative embodiments, the printed circuit board <NUM> may be any suitable controller coupled to the motor <NUM>, the switch <NUM>, or the indicator LEDs <NUM>. The printed circuit board <NUM> may comprise one or more microcontrollers, an oscillator crystal, motor control transistors, power regulating circuitry, LEDs, user switches, and other circuitry necessary to operate the instrument or provide feedback to users. The printed circuit board <NUM> may be configured to detect whether or not a cartridge is attached to the instrument. In one embodiment, the printed circuit board <NUM> detects whether or not the cartridge is attached by differences in voltage (such as by back EMF) generated by the motor when rotating with and without the attached cartridge. For example, the instrument comprises a plurality of reference points from which the printed circuit board <NUM> can measure voltage among the plurality of reference points. Such detection may be advantageous because an additional switch to activate the instrument will not be necessary, reducing the instrument cost and making the instrument easier to use. The printed circuit board <NUM> can be configured to provide variable power to the motor for specified intervals of time in order to mix and spin the cartridge as described above. Furthermore, the printed circuit board <NUM> can be configured to control illumination of indicator LEDs <NUM> to notify a user of significant events including completion of an assay. The lid may comprise a structure <NUM> which closes on the cartridge <NUM> during lid closure, the structure <NUM> configured to ensure secure attachment of the cartridge <NUM> to the motor <NUM> during operation. The instrument may be powered by an external AC-DC power converter <NUM> or other suitable power mechanism configured to plug into an electrical socket or may contain alternately or additionally a set of batteries configured to provide electrical power. If electrical power is provided by batteries, the printed circuit board <NUM> may be configured to adjust power provided to the motor to maintain consistent spin rates and compensate for variations in battery voltage. In addition, the printed circuit board <NUM> can be configured to terminate rotation and display warning signs such as flashing LEDs if battery voltage decreases below a threshold level. The lid or enclosure may also comprise a latch configured to prevent rotation of the cartridge when the lid is open, ensuring safety for the user. The lid or enclosure may also include a switch or other mechanism configured to trigger instrument operation. In some embodiments, the lid may include one or more magnets that trigger activation of the motor or other operations of the instrument when the one or more magnets are brought a threshold distance away from one or more sensors in the instrument. Such embodiments may be advantageous because an additional switch to activate the instrument is not required and instrument cost is reduced, making it easier and/or more intuitive to use.

<FIG> shows a top view, a side view, a configuration <NUM> view and a configuration <NUM> view of another embodiment of a configuration of a cartridge <NUM> and instrument <NUM> intended for use in fluorescent detection assays. The configuration can also be used for visual inspection methods. Any of the cartridges described throughout can be used with the configuration. The instrument comprises an impinging element <NUM> that comprises flexible material and intersects with a portion of the cartridge or a catch feature on the cartridge <NUM> configured to stop the cartridge at a specified location within the instrument. The flexible material of the impinging element <NUM> or material of the cartridge catch feature <NUM> may be selected such that, due to the flexible material, the cartridge is configured to rotate freely while the motor provides sufficient power. However, the cartridge is configured to stop at a specified location when power is reduced or withdrawn from the motor. Therefore, a portion <NUM> of the cartridge to be analyzed can be aligned with a light source <NUM> and/or photodetector <NUM> for static analysis without additional control inputs from the instrument. The photodetector and light source may be positioned on opposite sides of the cartridge as shown in configuration <NUM> of <FIG> or at an angle from each other on the same side, such as top or bottom, of the cartridge as shown in configuration <NUM> of <FIG>.

<FIG> demonstrates mechanical agitation of fluid, such as semen, or other viscous or particulate containing samples. A cartridge <NUM> contains a central cavity <NUM> which receives the fluid <NUM>. This may be used with any of the cartridges described throughout. The central cavity may contain dense objects <NUM> which comprise a diameter larger than diameter or width of fluidic channels <NUM>, the fluidic channels <NUM> directed radially outward from the central cavity. The cartridge may be accelerated first in a first direction <NUM>, then in a second direction <NUM> and then continuing this alternating motion for a defined interval of time. Alternately, the cartridge may be accelerated in the first direction <NUM> and allowed to come to a stop, with this pattern of accelerating in one direction and stopping repeated for a defined interval of time. These motion patterns causes agitation of the fluid and may cause any enclosed dense objects <NUM> to move relative to the fluid, aiding in mechanical agitation and configured to break down fluid viscosity or break up clumps of particles in the fluid.

<FIG> illustrates a side view of an instrument <NUM> and cartridge <NUM>, the instrument <NUM> and the cartridge <NUM>, the cartridge and instrument for fluid, semen or particulate analysis. The instrument may be used with any of the cartridges described throughout. The instrument comprises a motor <NUM>, a printed circuit board <NUM>, a motor enclosure <NUM>, a cartridge enclosure <NUM>, and power supply <NUM> such as a battery. In one embodiment, the motor enclosure <NUM> is tapered. In one embodiment, the cartridge enclosure <NUM> is form-fitting to the cartridge and openable. A user switch and indicator LEDs may also be included (not shown). The cartridge and cartridge enclosure are configured to be fully detachable from the instrument and may both be disposable. Once closed, the cartridge enclosure can be configured to be irreversibly bond together a first side and a second side of the cartridge, preventing the user from opening the cartridge during operation or following processing of the fluid. To prevent excessive noise, vibration, and movement of the instrument during operation, such as centrifugation, the instrument may comprise a securing mechanism <NUM>, such as a suction cup or rubber feet, attached to the bottom surface of the instrument. The instrument may comprise weighted ballast <NUM> in the form of dense material, such as metal plates, configured to prevent the instrument from tipping over during operation.

<FIG> illustrates another embodiment of an instrument <NUM> and a cartridge <NUM> for fluid, semen or particulate analysis in which the instrument is plugged into the cartridge and cartridge enclosure <NUM> from above. This may be used with any of the cartridges described throughout. The instrument comprises a motor <NUM>, control board <NUM>, motor enclosure <NUM>, cartridge enclosure <NUM>, and power supply <NUM> such as a battery. In one embodiment, the motor enclosure <NUM> is tapered. In one embodiment, the cartridge enclosure <NUM> is form-fitting to the cartridge. A user switch and indicator LEDs may also be included (not shown). The instrument may comprise weighted ballast in the form of dense material, such as metal plates, configured to prevent the instrument from tipping over during operation.

<FIG> diagrams an embodiment of a configuration of a cartridge enclosure <NUM> which is detachable from the instrument <NUM> (of <FIG>) and comprises a cartridge <NUM>. This may be used with any of the cartridges described throughout. The enclosure <NUM> may comprised a bottom half <NUM>, top half <NUM>, and a living hinge <NUM>. The enclosure <NUM> can be opened, as shown in <FIG>, configured to allow a user to add fluid to the cartridge <NUM>. Following fluid addition, the user may close the cartridge enclosure <NUM>. The combined cartridge <NUM> and closure <NUM> may be connected to the instrument <NUM> to rotate the cartridge <NUM> during centrifugation. In one embodiment, the cartridge and enclosure may be made from polymer and be disposable.

<FIG> illustrate embodiments in which additional liquid reagents are added to a cartridge to separate different types of particles from cells, such as sperm cells. Any of these embodiments may be used with any of the cartridges or instruments described throughout.

<FIG> illustrates an embodiment in which a liquid medium of defined density is used to separate particulates based on unique physical characteristics of the particulates. In one embodiment, the cartridge <NUM> is loaded with a volume of a density medium <NUM>; the density medium <NUM> comprises a fluid medium of a defined density. The density medium <NUM> occupies a defined volume of a sedimentation column <NUM> integrated into the cartridge <NUM>. The sedimentation column, the sample directing cavity, and the sample entry cavity of all cartridges described herein are configured to be able to hold the density medium. The density medium may be stored within a cartridge or included as part of a kit. The sample fluid is loaded through a central cavity <NUM> of the cartridge and the cartridge is spun at a specified rotation rate for an interval of time such that a defined volume of the sample fluid layers upon the density medium <NUM> in the sedimentation column <NUM>. During centrifugation, particulates in the sample fluid that comprise a higher density than density of the density medium <NUM> will sediment to the end of the sedimentation column during centrifugation, forming a pellet <NUM>. The height of the pellet <NUM> may be measured to estimate initial concentration of higher density particulates as described previously. Excess fluid and particulates comprising a density less than density of the density medium will remain suspended as a supernatant <NUM>. The sample fluid may comprise semen, and the particulates may comprise sperm cells. The unique physical characteristics of the sperm cells may comprise a density, the density characteristic of cell motility, viability, or morphology. In some embodiments, the density medium may comprise a fluid of specified density configured to separate sperm cells from other particulates found in semen such as cell fragments and leukocytes (i.e. the density medium is less dense than the sperm cells and denser than the other particulates). In this embodiment, the pellet <NUM> may be measured to estimate the concentration of sperm cells without interference from other particulates in semen. In some embodiments, the density medium <NUM> may comprise a fluid of specified density configured to separate motile from non-motile sperm cells (i.e. the density medium is more dense than non-motile sperm cells and less dense than motile sperm cells). In this embodiment, the pellet <NUM> may be measured to estimate the concentration of motile sperm cells. In another embodiment, the density medium <NUM> may comprise a specified density configured to isolate X-chromosome containing sperm cells from Y-chromosome containing sperm cells (X-chromosome containing sperm cells are on average denser than Y - chromosome containing sperm cells).

<FIG> diagrams an embodiment of a cartridge <NUM> in which two or more liquid density media comprising defined densities are loaded into a sedimentation column <NUM>, forming a continuous or discontinuous density gradient. Particulates in the sample may be separated based on unique physical characteristics of the particulates and separate into the density gradient. In one embodiment, the density media comprise a first density medium <NUM>, first loaded into the sedimentation column <NUM>, and a second density medium <NUM>, loaded into the sedimentation column <NUM> following the first density medium <NUM>. The sample fluid is loaded through a central cavity <NUM> of the cartridge <NUM> and the cartridge is spun at a specified rotation rate for an interval of time such that a defined volume of the sample fluid layers upon the density media <NUM> and <NUM> in the sedimentation column. During centrifugation, particulates comprising a density higher than density of the first density medium <NUM> and density of the second density medium <NUM> will form a pellet <NUM> at the bottom of the sedimentation column. Particulates comprising a density lower than density of the first density medium <NUM> but higher than density of the second density medium <NUM> will concentrate at an interface <NUM> of the two density media <NUM> and <NUM>. Excess sample fluid and particulates comprising a density less than the density media <NUM> and <NUM> will remain suspended as supernatant <NUM>.

<FIG> illustrates an embodiment of a cartridge <NUM> in which two or more liquid density media comprising defined densities are loaded into two sedimentation columns <NUM> and <NUM> on the cartridge. A first sedimentation column <NUM> is filled with a first density medium <NUM>, while a second sedimentation column <NUM> is filled with a second density medium <NUM>. For example, the clinical fluid is loaded through a central cavity <NUM> and the cartridge is centrifuged at a specified rotation rate for an interval of time such that a defined volume of the sample layers upon each pre-loaded density media <NUM> and <NUM> in the individual sedimentation columns <NUM> and <NUM>, respectively. During centrifugation, particulates in the clinical fluid are isolated based on density in each sedimentation column, forming pellets <NUM> and <NUM> at the end of each sedimentation column <NUM> and <NUM> respectively. Excess clinical fluid and particulates comprising a density less than density of either density media will remain suspended as supernatants <NUM> and <NUM>. This embodiment may be extended to a plurality of sedimentation columns and density media. For example, certain embodiments may comprise a cartridge with three or more sedimentation columns, each containing zero, one, or more density media.

<FIG> illustrates an embodiment of a cartridge in which diffusion is used to isolate motile from immotile cells, such as sperm cells, prior to centrifugation, thereby enabling quantification of total cells and percent of cell motility. The fluid is loaded to the sample inlet channel <NUM> and a sheath fluid is loaded into the corresponding inlet channel <NUM> on the other side of the central section <NUM> of the cartridge. The fluid and sheath fluid flow via gravity-driven flow or other pressure source from one side to the other side of the central section <NUM>. Within the joint central channel <NUM>, motile cells are able to swim from the sample inlet fluid stream including inlets <NUM> and <NUM> to the sheath fluid stream including outlets <NUM> and <NUM>, thereby separating from immotile cells which remain in the lower channel. Following separation, the cartridge is rotated at a specified rotation rate for an interval of time such that motile cells in the upper channel are transported to the upper sedimentation channel, while cells in the lower channel are transported to the lower sedimentation channel. Following rotation, volumes of pellets <NUM> and <NUM> in the upper and lower sedimentation channels, respectively, are used to quantify total cell count and percent motility.

Claim 1:
An apparatus comprising:
a cartridge (<NUM>) configured to be rotated to cause sedimentation of particulates or cells in a received sample, the cartridge (<NUM>) comprising:
a central cavity (<NUM>) centred at a rotation centre of the cartridge (<NUM>), configured to hold the received sample;
a sedimentation column (<NUM>) configured to be in fluid communication with the central cavity (<NUM>), the sedimentation column (<NUM>) comprising:
a channel or a second cavity with a cross-sectional area that is less than a cross-sectional area of the central cavity (<NUM>);
a sample directing cavity (<NUM>) comprising a first opening connected to the central cavity (<NUM>) and a second opening connected to the sedimentation column (<NUM>), the first opening comprising a first cross-sectional area and the second opening comprising a second cross-sectional area that is less than the first cross-sectional area, the sample directing cavity (<NUM>) configured to hold a defined volume of the received sample and configured to direct cells into the sedimentation column (<NUM>) during rotation of the cartridge (<NUM>); and wherein the cartridge (<NUM>) further comprises a length and a width, wherein the length is more than twice the width, characterized in that
the apparatus further comprises a counterbalance cavity (<NUM>) connected and in fluid communication with the central cavity (<NUM>), the counterbalance cavity (<NUM>) configured to counterbalance the sample directing cavity (<NUM>) during rotation of the cartridge (<NUM>).