Patent ID: 12203928

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is now made toFIG.1, which is a flowchart showing at least some steps of a method that is performed, in accordance with some applications of the present invention.

Typically, in a first step22saliva or another body fluid from a subject is introduced into (e.g., absorbed within) a stationary phase (e.g., a stationary-phase adsorbent). The stationary phase may be configured to adsorb an analyte from the saliva, if the analyte is present. Typically, the stationary phase is cellulosic. For example, the stationary phase may include cotton, carboxymethyl cellulose (CMC), or both. For some applications, a ratio of cotton to CMC within the stationary phase is between 5:1 and 50:1 (e.g., between 10:1 and 25:1).

For some applications, in a second step24, a portion of the absorbed saliva (i.e., an eluate) is extracted from the stationary phase, by applying pressure to the stationary phase. For example, and as described in more detail hereinbelow, a dedicated pressure-applying mechanism may be used for extracting the portion of the absorbed saliva from the stationary phase. For example, two or more pressure-applying surfaces may be configured to squeeze the stationary phase therebetween, in response to a subject pushing and/or otherwise applying pressure to one of the pressure-applying surfaces. It is noted that step24is optional (as indicated by the dashed box around step24), and for some applications, the method proceeds to step26, without step24being performed prior to step26.

In a third step26, the analyte (if any is present) is eluted from the stationary phase, by passing an eluent through the stationary phase, the resulting eluate containing the analyte. For some applications, the eluent contains a protein, such as an albumin, such as a serum albumin (e.g., a mammalian serum albumin, such as bovine serum albumin (BSA) or human serum albumin (HSA)) or an egg albumin (e.g., ovalbumin).

For some applications, steps22,24, and/or26are performed simultaneously with each other. For example, the saliva and the eluent may be passed through the stationary phase simultaneously with each other. Alternatively or additionally, pressure may be applied to the stationary phase at the same time as passing the eluent through the stationary phase adsorbent. For some applications, agents are predisposed upon the stationary phase-adsorbent or upon another element (e.g., in dried or powdered form), as described in further detail hereinbelow. Typically, passing through the stationary phase adsorbent (and/or passing through the stationary phase and then being eluted from the stationary phase, and/or passing through the stationary phase that has the agents disposed thereon), causes the medium within which the analytes are disposed to change, in a manner that increases the detectability of the analytes.

In a fourth step28, the analyte (if any is present), having passed through the stationary phase is detected, e.g., in order to determine a condition of the subject. For some applications, the presence and/or concentration of the analyte is detected using an immunochemical test, such as a lateral flow test, e.g., such as is used in urine dipstick tests, mutatis mutandis. Alternatively or additionally, other techniques are used to detect the presence and/or concentration of the analyte. For example, spectrophotometry, mass spectrophotometry, chromatography, or other chemical or physical tests may be used.

Reference is now made toFIG.2, which is a schematic illustration of a method that is performed, in accordance with some applications of the present invention. For some applications,FIG.2is an alternative representation of the technique described with reference toFIG.1.

A body fluid (e.g., saliva, urine, blood)40of a subject is introduced into a stationary phase44. Stationary phase44is typically cellulosic. For example, stationary phase44may comprise cotton, CMC, or both. A protein, such as an albumin42, is also introduced into stationary phase44. It is to be noted that although the present application typically refers to albumin42, for some applications a different protein may be used.

For some applications, fluid40and albumin42are introduced separately into stationary phase44. This is represented by arrows60aand62a, respectively. For some such applications, fluid40is introduced first, and the albumin is introduced subsequently, e.g., as a component of an eluent, e.g., as described hereinabove. Alternatively, albumin42may be introduced first, and fluid40is introduced subsequently.

For some applications, fluid40and albumin42are introduced simultaneously (e.g., together) into stationary phase44. This is represented by converging arrows60band62b. For some such applications, albumin42is mixed and/or dissolved into fluid40, and the mixture/solution is introduced into stationary phase44. An example of such an application is described with reference toFIGS.3and4A-B.

An eluate46is extracted from stationary phase44. If fluid40contained the analyte of interest, eluate46contains the analyte. An assay50is performed on eluate46, in order to determine a property of the analyte within the eluate—e.g., the presence and/or concentration of the analyte within the eluate.

It is hypothesized by the inventors that the method described herein, in which fluid40is exposed to stationary phase44in the presence of albumin42, increases the sensitivity, specificity, and/or reproducibility of assay50, compared to performing the assay on fluid40without performing this method.

For some applications, a surfactant, typically a polyoxyethylene-polyoxypropylene block copolymer48, is introduced prior to analysis50. For some such applications, copolymer48is introduced into to stationary phase44. For example, copolymer48may be introduced separately from fluid40and albumin42(represented by arrow68a), or simultaneously/together with the fluid and the albumin (represented by arrow68b), such as by being mixed and/or dissolved into fluid40. Alternatively or additionally, copolymer48may be introduced subsequently to the extraction of eluate46from stationary phase44(represented by arrow68c), such as by mixing and/or dissolving the copolymer into eluate46. For some applications, copolymer48is poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (e.g., Synperonic® F 108).

It is hypothesized by the inventors that such use of copolymer48further increases the sensitivity, specificity, and/or reproducibility of assay50, e.g., for applications in which assay50is a lateral flow test. For example, copolymer48may improve flow through the lateral flow strip.

For some applications, the analyte comprises human chorionic gonadotropin (HGC). For example, the presence and/or concentration of HCG may be detected, and it is determined that the subject is pregnant or not pregnant, based upon the detected presence and/or concentration of HCG. Alternatively or additionally, a stage of a subject's pregnancy may be determined based upon the determined presence and/or concentration of HCG.

For some applications, the analyte comprises luteinizing hormone (LH). For example, the presence and/or concentration of LH may be detected, and based upon the detected presence and/or concentration of LH, a stage in the menstrual cycle of the subject may be determined—e.g., it may be determined whether the subject is currently ovulating.

For some applications, the analyte comprises histidine-rich protein (HRP) II and/or pan-Plasmodium antigen lactate dehydrogenase. For example, the presence and/or concentration of histidine-rich protein 2 and/or pan-Plasmodium antigen lactate dehydrogenase is detected, and it is determined that the subject is suffering from malaria, or is not suffering from malaria, based upon the detected presence and/or concentration of histidine-rich protein 2 and/or pan-Plasmodium antigen lactate dehydrogenase.

For some applications, the analyte comprises aHelicobacter pylori(H. pylori) antigen, such as CagA. For example, the presence and/or concentration of theH. pyloriantigen is detected, and it is determined that the subject carriesH. pylori, or does not carryH. pylori, based upon the detected presence and/or concentration of theH. pyloriantigen.

For some applications, the analyte comprises aCandidaspp. (e.g.C. albicans) antigen, such asCandida albicansenolase. For example, the presence and/or concentration of theCandidaantigen is detected, and it is determined that the subject carriesCandida, or does not carryCandida, based upon the detected presence and/or concentration of theCandidaantigen.

For some applications, the analyte comprises a medical or recreational drug, a component thereof, and/or a metabolite thereof. For example, the presence and/or concentration of tetrahydrocannabinol (THC) is detected, and it is determined that the subject has consumed cannabis or a cannabis product, based upon the detected presence and/or concentration of THC. Alternatively or additionally, a concentration of the drug, drug component, or component thereof within the subject (e.g., within the blood of the subject) may be determined based upon the detected presence and/or concentration of the drug, drug component, or component thereof. Alternatively or additionally, the time since consumption of the drug may be determined based upon the detected presence and/or concentration of the drug, drug component, or component thereof. For applications in which the drug is a medical drug, dosing of the medical drug may also be controlled and/or adjusted based on the detected presence and/or concentration of the drug, drug component, or component thereof.

As described hereinabove, for some applications, a cellulosic stationary phase is used in conjunction with the techniques described herein. In experiments performed by the inventors of the present application, the concentration of HCG in saliva samples was measured. Subsequently, the saliva samples were absorbed into a stationary phase that included cotton and carboxymethyl cellulose at a cotton:CMC ratio of between 10:1 and 25:1, and the saliva portions were then squeezed out of the adsorbent. It was found that the concentration of HCG in the saliva samples after the samples had been absorbed and then extracted from the stationary phase was substantially reduced relative the original concentrations in the respective samples. These results indicate that a cellulosic stationary phase (e.g., comprising cotton and/or CMC) is effective at adsorbing at least some analytes from saliva. Therefore, in accordance with some applications of the present invention, a cellulosic stationary phase is used.

For some applications, saliva from the subject is collected in a receptacle. Subsequently, the saliva is passed through a cellulosic stationary phase-adsorbent. For some applications, the stationary phase comprises cotton and CMC, e.g., at a cotton:CMC ratio of between 5:1 and 50:1 (e.g., between 10:1 and 25:1). For some applications, agents are disposed upon the stationary phase adsorbent (e.g., in dried and/or powdered form). Typically, passing through the stationary phase adsorbent (and/or passing through the stationary phase, which has the agents disposed thereon), causes the medium within which the analytes are disposed to change, in a manner that increases the detectability of the analytes. Typically, the analyte (if any is present), having passed through the stationary phase is detected in order to determine a condition of the subject, e.g., in accordance with the techniques described hereinabove. It is noted that the technique described in this paragraph differs from techniques in which a stationary phase is used for the purpose of collecting a subject's saliva, such that the saliva may then be analyzed. Rather, in accordance with the technique described herein, saliva that has already been collected is made to pass through the stationary phase, typically, for the purpose of increasing the detectability of analytes that are present within the saliva.

Reference is now made toFIGS.3and4A-B, which are schematic illustrations of a system100for use with a body fluid of a subject, in accordance with some applications of the invention. As described hereinabove (e.g., with reference toFIG.2), for some applications, albumin42is mixed and/or dissolved into body fluid40, and the mixture/solution is introduced into stationary phase44—represented by converging arrows60band62bofFIG.2. System100is typically configured to facilitate such a technique, mutatis mutandis.

System100comprises an elongate barrel162and a plunger122. Typically, plunger122is defined by, or is a component of, a first structure120of system100. Typically, barrel162is defined by, or is a component of, a second structure160of system100. Each of structures120and160typically comprises several integrated components, e.g., that are fixed with respect to each other. Typically, structures120and160are separate from each other (e.g., are provided uncoupled to each other), and are coupled to each other by the user during normal use, as described hereinbelow.

Barrel162is shaped to define a channel164therethrough, and has an opening166into the channel at a proximal region of the barrel, and an outlet168from the channel at a distal region of the barrel.

A porous carrier170is disposed within channel164. A cellulosic stationary phase144(e.g., comprising cotton and/or CMC) is disposed within channel164between carrier170and the distal region of the barrel (e.g., between the carrier and outlet168). A protein, such as an albumin (e.g., BSA)142is held in carrier170, e.g., having been dried therein.

For some applications, stationary phase144generally corresponds to stationary phase44ofFIG.2. For applications in which stationary phase144comprises both cotton and CMC, the stationary phase typically has a cotton:CMC ratio of between 5:1 and 50:1 (e.g., between 10:1 and 25:1). For some applications, albumin142generally corresponds to albumin42ofFIG.2.

For some applications, and as shown, system100(e.g., structure160) further comprises a lateral flow platform190, coupled to the distal region of barrel162such that the lateral flow platform (e.g., a sample pad192thereof) is in fluid communication with outlet168. Lateral flow platform190is configured to detect the analyte of interest (such as an analyte described herein), comprising a lateral flow test comprising antibodies specific to that analyte—e.g., similar to existing lateral flow tests, mutatis mutandis.

A distal portion124of plunger122is introducible into channel164via opening166(FIG.4A), and is dimensioned to slide snugly within the channel (FIG.4B). If a body fluid is disposed within channel164proximal from stationary phase144and carrier170, progressive advancement of plunger122distally through the channel (i) pushes the body fluid through carrier170, where the fluid mixes with and/or dissolves albumin142, (ii) pushes the body fluid and the mixed/dissolved albumin into stationary phase144, and (iii) pushes the resulting eluate out of the stationary phase, and through outlet168, e.g., to lateral flow platform190.

For some applications, movement of the body fluid along channel164through carrier170and into stationary phase144is achieved by advancing plunger122(e.g., distal portion124thereof) through a first portion of the channel (e.g., a first distance through the channel). For some applications, the eluate is extracted from stationary phase144by advancing plunger122(e.g., distal portion124thereof) through a second portion of channel164(e.g., a second distance through the channel). For some such applications, and as described hereinbelow, this applies pressure to (e.g., compresses) the stationary phase, thereby serving as a pressure-applying mechanism for extracting the eluate from the stationary phase.

Typically, and as shown, system100(e.g., structure120thereof) comprises a sponge130, coupled to distal portion124of plunger122. For some applications, and as shown, distal portion124of plunger122defines a crown126at a distal end of the plunger, and a piston ring128, e.g., proximal from the crown. For such applications, sponge130is disposed distally from crown126, e.g., attached to a distal face of the crown.

Sponge130is configured to hold a fluid, such as a body fluid140, and structure120(e.g., plunger122thereof) is configured to introduce the sponge holding the fluid into channel164via opening166(FIG.4A). For some applications, body fluid140generally corresponds to body fluid40ofFIG.2. Typically, body fluid140is introduced into sponge130by bathing the sponge in the fluid. For example, for applications in which body fluid140is saliva, distal portion124of plunger122is placed in the mouth of the subject, where it absorbs the saliva. For such applications, sponge130is therefore configured to be safe for placement in the mouth of the subject. For example, sponge130is securely attached to plunger122, is non-toxic, and/or is sterile. Typically, sponge130contains no additional substances therein that may release and/or dissolve in the mouth of the subject. For some applications, sponge130comprises polymeric fibers.

Structure120(e.g., plunger122thereof) is dimensioned such that sliding of distal portion124through channel164compresses sponge130within the channel (FIG.4B). To facilitate this, sponge130is sufficiently compressible to be compressed by force applied via plunger122. Compression of sponge130holding body fluid140drives the body fluid (i) out of the sponge, (ii) through carrier170, dissolving at least some of albumin142disposed therein, (iii) with the dissolved albumin, into stationary phase144, and (iv) as an eluate, out of the stationary phase and through outlet168, typically to lateral flow platform190(e.g., the sample pad thereof).

Typically, sliding of distal portion124of plunger122through channel164compresses sponge130between plunger122and carrier170(e.g., pressing the sponge against the carrier—i.e., with the sponge in contact with the carrier).

For some applications, the dimensions of structure120(e.g., plunger122thereof) and the compressibility of carrier170are such that sliding of distal portion124of the plunger through channel164compresses the carrier between sponge130and stationary phase144.

For some applications, structure120(e.g., plunger122thereof) (i) comprises a screw thread121at a proximal portion, configured to couple the plunger to structure160(e.g., barrel162thereof), and (ii) is dimensioned such that coupling the plunger to the barrel using the screw thread compresses sponge130within the channel by sliding distal portion124of the plunger through the channel. This is illustrated by the helical arrow inFIG.4B. For such applications, structure160(e.g., barrel162thereof) typically comprises a corresponding screw thread161. Structure120(e.g., plunger122thereof) typically comprises a stem132that extends between screw thread121and distal portion124.

FIG.4Ashows structures120and160positioned with distal portion124of plunger122disposed within channel164but prior to engagement of screw threads121and161. As shown, in this state, sponge130typically remains largely (e.g., completely) uncompressed, e.g., such that compression of the sponge occurs primarily (e.g., only) via screwing of screw threads121and161. Also as shown, in this state, distal portion124(e.g., piston ring128thereof) is disposed sufficiently distally (i.e., deeply) within channel164to have sealed the channel, despite more proximal portions of the channel, closer to opening166, being typically wider. This therefore prevents inadvertent leakage of the body fluid during subsequent distal advancement of plunger122.

FIG.4Bshows structures120and160following complete distal advancement of plunger122, e.g., by screwing screw thread121as far as possible—e.g., until it reaches the end of screw thread161, and/or until distal portion124of the plunger cannot be advanced further distally. As shown, once system100is in this state, sponge130has become compressed, such that body fluid140has been squeezed out of the sponge, and through carrier170.

For some applications, and as shown, once system100is in the state shown inFIG.4B, carrier170has also become compressed (e.g., between sponge130and stationary phase144), thereby facilitating movement of fluid140and albumin142out of the carrier and through stationary phase144. That is, for some applications, the dimensions of structure120(e.g., plunger122thereof) and compressibility of carrier170are such that sliding of distal portion124of the plunger through channel164compresses the carrier between sponge130and stationary phase144.

For some applications, and as shown, once system100is in the state shown inFIG.4B, stationary phase144has also become compressed (e.g., between carrier170and the distal region of barrel162, such as between the carrier and outlet168), thereby facilitating movement of the eluate out of the stationary phase and through outlet168, e.g., to lateral flow platform190. That is, for some applications, the dimensions of structure120(e.g., plunger122thereof) and compressibility of stationary phase144are such that sliding of distal portion124of the plunger through channel164compresses the stationary phase between carrier170and the distal region of barrel162.

For some applications, sponge130is more compressible than carrier170, e.g., such that, before the carrier becomes maximally compressed, the carrier receives at least a portion (e.g., the majority of) of the body fluid that will be extracted from the sponge. For some applications, carrier170is more compressible than stationary phase144, e.g., such that, before the stationary phase becomes maximally compressed, the stationary phase receives at least a portion (e.g., the majority of) of the body fluid that will be extracted from the carrier. In this context, the term “maximally compressed” means as compressed as system100is configured to make the element during normal use.

For some applications, system100is configured such that carrier170is not compressed during normal use.

For some applications, system100is configured such that stationary phase144is not compressed during normal use.

FIG.3shows structures120and160aligned adjacent to each other in the same degree of advancement as in the state shown inFIG.4B. A comparison ofFIGS.3and4Billustrates that, for some applications, plunger122is sufficiently long that, in the state shown inFIG.4B, distal portion124of the plunger (e.g., crown126) is disposed at a position within channel164that, prior to introduction of the plunger into the channel, was occupied by stationary phase144.

The configuration of system100such that the body fluid moves through the system as described hereinabove is typically determined by one or more factors including the capacity and compressibility of sponge130, carrier170, and stationary phase144relative to each other.

For some applications, system100further comprises a polyoxyethylene-polyoxypropylene block copolymer (PPBC), positioned fluidically between carrier170and lateral flow platform190, inclusive. That is, the PPBC is disposed at a site that is at carrier170, at lateral flow platform190, or somewhere along the flow path of the body fluid therebetween. For some applications, the PPBC is held in the carrier, e.g., in a dried form, similar to as described hereinabove for the albumin, mutatis mutandis. For some applications, the PPBC is held in the lateral flow platform, e.g., on the sample pad thereof. For some applications, the PPBC is held in stationary phase144.

It has been identified by the inventors that inclusion of the PPBC further increases sensitivity and/or reproducibility of the assays performed on the eluate, e.g., the lateral flow test. For some applications, the PPBC is Synperonic® F 108 (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)), which the inventors have identified as having a particularly beneficial effect in this regard. Data showing the effect of the PPBC is shown inFIG.13.

Reference is now made toFIGS.5,6,7,8,9,10,11,12,13, and14, which show results of various lateral flow test assays, performed on untreated body fluids, or on body fluids treated according to various applications of the invention. In this context, a “treated” body fluid means the eluate derived from treating the body fluid according to an application of the invention.

FIG.5shows the results of lateral flow tests for HCG, performed on one of two body fluids: saliva or urine. The lateral flow test was a commercial pregnancy test originally intended for use with a urine sample. The results are shown as photographs of the respective test window.

The samples were taken from healthy male subjects, and therefore naturally do not contain HCG. Recombinant beta-HCG was added to the samples, to a final concentration of 10 mIU. A control was provided, to which beta-HCG was not added. The samples to which beta-HCG was added were either otherwise untreated, or were treated according to an application of the current invention, in which the fluid was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained. The control was treated according to the same application of the invention.

HCG was detected in untreated urine, and this positive result was enhanced in treated urine. HCG was not detected in untreated saliva, but was detected in treated saliva. No false positive result was seen for the control samples. Therefore, treatment of body fluid in accordance with an application of the invention enhances detection of an analyte in that body fluid.

FIG.6shows the results of lateral flow tests for luteinizing hormone (LH), performed on one of two body fluids: saliva or urine. The lateral flow test was a commercial ovulation test originally intended for use with a urine sample. The results are shown as photographs of the respective test window, as well as a semi-quantitative measurement of normalized optical density (arbitrary units).

The samples were taken from healthy female subjects during their ovulation period, during which the subjects naturally increase LH expression.

A positive result (a visible test line) was obtained from untreated urine. A negative result (no visible test line) was obtained from untreated saliva. However, a positive result was obtained from saliva treated according to an application of the current invention, in which the saliva was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained. Therefore, treatment of body fluid in accordance with at least one application of the invention enhances detection of an analyte in that body fluid.

FIG.7shows the results of lateral flow tests for malaria, performed on saliva. The lateral flow test was a commercial malaria test originally intended for detecting HRP II in a blood sample. The results are shown as photographs of the respective test window.

The samples were taken from malaria patients, and were either left untreated, or were treated in accordance with an application of the invention, in which the fluid was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained.

A negative result (no visible test line) was obtained from untreated saliva. However, a positive result (a visible test line) was obtained from treated saliva. Therefore, treatment of body fluid in accordance with at least one application of the invention enhances detection of an analyte in that body fluid.

FIG.8shows the results of lateral flow tests forH. pylori, performed on saliva. The lateral flow test was a commercialH. pyloritest originally intended for detectingH. pyloriin a fecal sample. The results are shown as photographs of the respective test window.

The samples were taken from healthy subjects, and an inactivatedH. pylorilysate was added to the samples to simulateH. pyloriinfection. Samples were either left untreated, or were treated in accordance with an application of the invention, in which the fluid was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained.

A negative result (no visible test line) was obtained from untreated saliva. However, a positive result (a visible test line) was obtained from treated saliva. Therefore, treatment of body fluid in accordance with at least one application of the invention enhances detection of an analyte in that body fluid.

FIG.9shows the results of lateral flow tests forC. albicans, performed on saliva. The lateral flow test was a commercialCandidatest originally intended for detectingCandidain a vaginal sample. The results are shown as photographs of the respective test window.

The samples were taken from healthy subjects, andCandidacells were added to the samples to a final concentration of 50,000 cells/ml to simulateCandidainfection. Samples were either left untreated, or were treated in accordance with an application of the invention, in which the fluid was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained.

A negative result (no visible test line) was obtained from untreated saliva. However, a positive result (a visible test line) was obtained from treated saliva. Therefore, treatment of body fluid in accordance with at least one application of the invention enhances detection of an analyte in that body fluid.

FIG.10shows the results of lateral flow tests for THC, performed on saliva. The lateral flow test was part of a commercial multipanel test, and was originally intended for detecting THC in a saliva sample. This particular test is a competition assay—discussed below. The results are shown as photographs of the respective test window.

The samples were taken from healthy subjects, and THC was added to the samples to a final concentration of 25 ng/ml. Samples were either left untreated, or were treated in accordance with an application of the invention, in which the fluid was introduced to the stationary phase, an albumin-containing eluent was subsequently introduced to the stationary phase, and an eluate was obtained.

A negative result was obtained from untreated saliva. (Because this test is a competition assay, the presence of a test line represents a negative result). However, a positive result was obtained from treated saliva. (Because this test is a competition assay, the absence of a test line represents a positive result). Therefore, treatment of body fluid in accordance with at least one application of the invention enhances detection of an analyte in that body fluid.

FIGS.11-12show results of lateral flow tests for HCG using saliva that either was untreated, or was treated in accordance with an application of the invention, e.g., as described with reference toFIGS.1-2, mutatis mutandis. More specifically, different cellulosic stationary phases were used. The saliva used was from healthy female subjects in early pregnancy (0-1 days after a missed period), and therefore contained HCG, albeit at a low level.

FIG.11shows that saliva, not treated in accordance with an application of the invention, did not generate a visible test line or a control line.FIG.11also shows that treatment of the saliva in accordance with an application of the invention did result in a visible control line and a visible test line, whether the stationary phase that was used comprised CMC, cotton, or a combination thereof.

FIG.12shows results from saliva, treated in accordance with an application of the invention, whereby the stationary phase comprised a commercially-available dental roll, comprising cellulosic fibers. Strip1shows the result from saliva that had been treated in accordance with an application of the invention in which the stationary phase used was Roeko Luna dental roll from Coltene/Whaledent GmbH (Germany). Strip2shows the result from HCG-containing saliva that had been treated in accordance with an application of the invention in which the stationary phase used was dental cotton roll from Naot Medical (Israel), containing 99.5 percent cotton, and 0.5 percent CMC. Strip3shows the result from HCG-containing saliva that had been treated in accordance with an application of the invention in which the stationary phase used was dental cotton roll from DENTaccess (Israel), containing 99.5 percent cotton, and 0.5 percent croscarmellose sodium (an internally cross-linked sodium carboxymethylcellulose). As shown, in each of these cases, control and test lines were visible.

FIG.13shows results from results of lateral flow tests for HCG using saliva that was treated in accordance with an application of the invention, e.g., as described with reference toFIGS.1-2, mutatis mutandis. More specifically, the experiments that generated the data inFIG.13were performed using system100, mutatis mutandis.

Various surfactants were added to the saliva, to a concentration of 0.5%, and a negative control received no surfactant. For each surfactant, a negative control saliva that did not contain HCG was compared with saliva containing a low concentration of HCG. The HCG-negative saliva was obtained from healthy subjects who were known not to be pregnant. The HCG-low saliva was obtained from health subjects in early pregnancy (0-1 days after a missed period), and therefore contained HCG, albeit at a low level. The intensity of the test line of each lateral flow test was semi-quantitively measured using a reflectance reader (Axxin, Australia).

The absence of bars for no surfactant, Tergitol, and Tetronic 90R4 is due to poor visualization on the test strips, resulting from poor flow characteristics. The test line intensity for these test strips was not measured. In addition to good flow characteristics, it is desirable that assay50(e.g., a lateral flow test) provides a visible test line for samples that contain the analyte (sensitivity) but not for samples that do not contain the analyte (false positives). Although several of the surfactants tested provided a test line for the HCG-containing saliva that was more intense than corresponding test line for the HCG-negative saliva, the intensity of the test line for the HCG-negative saliva was nonetheless higher than the inventors deem optimal. Synperonic® F 108, Brij® 35 (polyethylene glycol dodecyl ether), and Pluronic® F 68 (polyoxyethylene-polyoxypropylene block copolymer) resulted in advantageously low-intensity test lines for the HCG-negative saliva, and advantageously higher-intensity test lines for the HCG-containing saliva. Of these, Synperonic® F 108 provided the most intense test line for the HCG-containing saliva. Therefore, as described hereinabove, for some applications Synperonic® F 108 (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)), is introduced prior to analysis50.

FIG.14shows results of lateral flow tests for HCG using saliva that was treated in accordance with an application of the invention, e.g., as described with reference toFIGS.1-2, mutatis mutandis. More specifically, different albumins were used: human serum albumin (HSA) and bovine serum albumin (BSA). For each albumin, a negative control saliva that did not contain HCG was compared with saliva containing a low concentration of HCG. The HCG-negative saliva was obtained from healthy subjects who were known not to be pregnant. The HCG-low saliva was obtained from healthy female subjects in early pregnancy (0-1 days after a missed period), and therefore contained HCG, albeit at a low level.

FIG.14shows that the HCG-negative saliva did not result in a visible test line, whether HSA or BSA was used.FIG.14also shows that, whichever of the albumins was used, the HCG-low saliva resulted in a visible test line. All of the tests had visible control lines.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.