IES60894B2 - Apparatus for the collection and recovery of saliva for use in diagnostic assays - Google Patents

Description

Apparatus for the collection and recovery of saliva for use in diagnostic assays This invention relates to apparatus for the collection and recovery of saliva for use in diagnostic assays.

Diagnosis of a disease state in a subject frequently requires testing of a body fluid or tissue. Blood or a blood fraction is currently the body fluid which is the basis of the majority of diagnostic testing. However, blood collection is an invasive technique which can be hazardous.

Diagnostic tests which provide rapid responses and utilise simple, non-invasive technologies have become increasingly accepted because of their reliability, ease of use and convenience. For example, the majority of pregnancy testing is currently carried out by rapid, immunoassay-based tests using urine. Chemical dipstick tests for the detection of various substances in urine have been routinely used in hospitals, clinics, doctors’ surgeries and homes for several years.

Increasing concerns with the risk of obtaining blood samples through routine blood sampling (venipuncture), in particular because of the fear of accidental contraction of the Human Immunodeficiency 20 Virus (HIV) and ultimately full blown Acquired Immunodeficiency Syndrome (AIDS) and hepatitis, have resulted in the need to replace blood testing with non-invasive test methods which can provide equally accurate results. The risks of accidental AIDS infection by healthcare professionals, the fear of the general public of contracting infection 25 from healthcare professionals, and concerns of both groups over the disposal of blood contaminated waste should favour the use of nonblood based diagnostic tests.

It is estimated that AIDS will kill more than twenty million people worldwide by the year 2000 according to the United Nations 30 Development Programme. The World Health Organisation (WHO) indicates that from nine to eleven million adults and one million infants 860894 worldwide have become infected with HIV and that a significant number remain undiagnosed. Heterosexual transmissions now account for over 90% of the new cases of HIV infections worldwide. WHO estimates that the number of HIV infections will at least triple and possibly quadruple in the next eight years.

Screening and diagnostic tests for the detection of infectious diseases and other purposes have traditionally used blood and blood fractions, such as serum. Such use of blood in infectious disease diagnostics originated when the technologies were less sensitive than they are now, and required a relatively high concentration of antibodies present in serum. More recent technology, including enzyme-linked immunosorbent assays (commonly referred to as ELISAs), has greatly increased the sensitivity and specificity of immunological methods, allowing for better detection of very small quantities of antibody in solution.

The increased sensitivity of the diagnostic tests means that other body fluids, such as saliva and urine, can also be used in the diagnosis of many diseases or conditions. Furthermore, saliva has significantly fewer proteins than blood, potentially increasing the specificity of saliva-based tests and reducing the number of false positive results. Recent medical studies have determined that antibodies to HIV can be found in mucosal transudate, which is the antibody carrying component of saliva. This relationship is analogous to the relationship of blood serum to whole blood.

The oral immune system interacts actively with the immune system of the rest of the body. Within the oral cavity there is found a specific site of antigen-antibody response which involves extraoral lymph nodes and intraoral lymphoid aggregations.

By saliva herein is included gingival liquid, hereinafter referred to collectively as saliva.

Saliva contains a complex mixture of inorganic and organic substances: these can be broadly subdivided into electrolytes, hormones, enzymes, proteins, low molecular weight compounds and vitamins.

* The intraoral lymphoid tissue comprises essentially four distinct tissue aggregations: the gingival lymphoid tissue; salivary gland lymphoid tissue; scattered sub-mucosal lymphoid aggregations; and the tonsils.

The tonsils produce B and T cells. The predominant antibody formed by the tonsils is IgG. The tonsils also produce IgA, IgE and 10 IgM antibodies in smaller amounts.

The salivary glands produce and secrete through their plasma cells predominantly IgA. The IgA antibodies produced by the salivary glands are referred to as the secretory IgA and they represent the major immunoglobulin fraction contained in saliva.

It is found that although IgA is the predominant Ig class present in saliva, viral-specific IgG and IgM is reliably detectable in infected individuals.

The gingival lymphoid tissue also contains plasma cells which are located generally near the blood vessels and produce IgG and very little 20 IgA. It has been shown that the IgG secreted by the gingival lymphoid tissue is directly related to the IgG found in the blood.

The presence of IgG and secretory IgA in the saliva prompted the use of saliva as a basis for immunological assays. The suitability of saliva as a diagnostic body fluid has not been demonstrated for all , 25 diseases or even a significant proportion thereof. Recent studies have demonstrated that saliva can be successfully used in testing for various 4 conditions and diseases, including HIV antibody detection, rubella and hepatitis.

If one is to successfully use saliva as a diagnostic body fluid, several key factors must be taken into consideration: a) the type of antibody to be detected or determined; b) assay sensitivity; and c) the method of saliva collection.

As indicated above, IgA antibodies are the major immunological fraction contained in saliva. In many instances, there are not enough specific IgA antibodies in saliva to perform a specific diagnostic test. Furthermore, the specific IgA may not be present in a sufficient amount to perform a test that compares favourably with a corresponding blood test. An example of the latter is the case of HIV1 antibodies.

It is known that saliva contains about 0.01-0.1% of the immunoglobulins contained in the blood. Because of the reduced immunoglobulin content of saliva relative to blood, it is necessary to use more sensitive antigen-antibody assay methods relative to corresponding assays performed on the blood or blood fractions.

The collection of saliva is a relatively complicated procedure and can lead to misleading results when the saliva is collected from the salivary glands because of the relatively small volumes that can be collected and because of the viscosity and high mucous content of saliva. Most of the methods currently employed involve collecting saliva through capillary tubes, suctioning into micro-pipettes or syringes. The use of saliva collected by the latter methods has inherent problems because of the high content of mucous and the limitations presented by the predominance of IgA, which is known not to be present in a sufficient amount in the case of certain specific antibodies.

In recent years much attention has been directed to the use of saliva for diagnostic purposes and new methods of saliva collection have been developed to collect IgG antibodies. Many of the new methods involve the absorption of saliva in the mouth by an absorbent material from which the collected saliva is extracted and processed. With such methods a number of potential problem areas arise: i) the volume of sample collected; ii) the manipulation of the collected sample; iii) the mucous and tissue content of the collected sample; iv) the separation of the immunoglobulins from the mucous, tissue and saliva; v) the preservation or non-preservation of the immunoglobulins; vi) patient comfort during collection; and vii) the type of immunoglobulins collected.

One major advantage of the use of saliva as a body fluid for diagnostic assays is that the taking of saliva samples is non-invasive as compared with the taking of blood samples. Thus, the collection of 10 saliva for such assays can be carried out in situations where the availability of syringes might be limited or where strict hygiene practices might not be adhered to.

We have found that absorbent materials currently used to collect saliva are usually cotton-based or based on other natural fibres such as 15 paper and sponge and have a high affinity for organic substances contained in saliva, in particular, protein material and especially immunoglobulin, which is the most usual analyte targeted for diagnostic purposes. Because of this high binding, the saliva once collected must be treated chemically to release the analyte of interest.

Such a treatment can affect the sensitivity and specificity of a diagnostic assay for the analyte.

Thus, in a study carried out by Chamnanpunt, J. and Phanuphak, P. of the Thai Red Cross Programme on AIDS, Bangkok, Thailand in which they evaluated a saliva collection device sold under the Trade 25 Mark OMNISAL (Saliva Diagnostic Systems) and found that it had no advantages relative to simple spitting. The aim of the study carried out was to determine whether the collection device is better than simple saliva spitting in improving the sensitivity and specificity of the tests or in preserving the anti-HIV activity in the collected saliva.

Chamnanpunt, J. and Phanuphak, P. found that compared to simple spitting, the saliva collection device had no benefit in increasing sensitivity of salivary anti-HIV testing or in preserving stored saliva.

Thus, there is a need for a saliva collection device which can be used to collect saliva in a sufficient volume to allow for the detection of an analyte of interest, while at the same time readily releasing the analyte when required, especially without the use of chemical releasing agents.

The use of saliva as a basis for diagnostic assays is desirable. However, the processing of saliva once collected currently involves the use of laboratory equipment and instrumentation, such that testing On the spot' cannot normally be carried out. Therefore, there is a need for a method of collecting saliva and processing the saliva once collected that can be performed at the site of collection, for direct use in a diagnostic assay.

The invention provides a device for the collection of saliva from the oral cavity, comprising a mass of saliva absorbing fibrous material having substantially no binding affinity for organic material contained in absorbed saliva, such that expression of saliva from the mass results in substantially all of the protein material being recoverable therefrom.

By organic material herein is meant inter alia enzymes, hormones, including protein hormones, proteins generally, including and especially immunoglobulins, vitamins and other low or high molecular weight compounds, including drugs.

An especially suitable fibrous material for use in the saliva collection device according to the invention is rayon. Other suitable materials include the synthetic material sold under the Trade Mark DACRON.

The use of rayon or other fibrous materials having substantially no affinity for organic material contained in saliva is especially advantageous in the case of protein, because it eliminates a common problem observed with such organic materials which is non-specific binding.

Thus, using a rayon absorbent pad or other material with a very low binding capacity for immunoglobulins obviates the need for the addition of agents to the absorbent material to prevent non-specific binding, which agents can cause problems for the patient when the 5 saliva collection pad is inserted in the oral cavity. Furthermore, the use of such agents can lead to problems as regards obtaining regulatory approval for a saliva collection device.

It has been found that rayon material has a high absorption capacity.

The fibrous material for use in the collection of saliva according to the invention can be presented in many forms and shapes.

Thus, the saliva can be collected by means of a pad of the fibrous material. In use, the absorbent pad is wiped over a surface in the oral cavity. The absorbent pad is suitably 1-3 cm in length and 0.5-1.5 cm 15 in diameter and allows for the collection of between 0.1-1.1 ml of saliva when used to collect saliva in accordance with the invention.

An absorbent pad when such is used to collect saliva in accordance with the invention can be mounted at the end of a handle to facilitate the collection of saliva and the transfer thereof, once collected, to the receptacle. Indeed, the absorbent pad and associated handle can resemble a device commonly used in the home and referred to as a cotton bud or tip or as sold under the Trade Mark Q-TIP.

The handle suitably has a length of 6-10 cm and a diameter of 1-3 mm.

The handle is preferably provided with a weakened line adjacent the absorbent pad which facilitates detachment of the handle once the absorbent pad has been inserted in the receptacle for recovery of the collected saliva. Once the pad has been inserted in the receptacle, the handle is broken at the weakened line through a snapping action. More specifically, the absorbent pad is inserted into the receptacle until the weakened line of the handle lines up with the top edge of the receptacle, the top edge providing resistance for said handle. Once the handle is detached, leaving the pad inside the receptacle, the handle is discarded.

Alternatively, the fibrous material can be presented as a ball which is inserted and retained in the mouth for a given period, followed by collection in a receptacle of a saliva recovery device hereinafter described.

The fibrous material is most suitably spherical or ovoid in shape for ease of use.

However, it will be appreciated that the mass of saliva absorbing material can be of any suitable shape which permits the collection of saliva, when the shaped mass is wiped over a surface in the oral cavity such as the gums or under the tongue for approximately 2 minutes. At the end of the collection period, the saliva impregnated mass or pad is removed from the mouth and transferred to the receptacle for processing of the saliva.

The invention also provides a device for the recovery of saliva from an absorbent, compressible saliva collection device, comprising a receptacle for the saliva collection device and means for compressing the saliva collection device to express saliva and entrained organic material therefrom and to cause egress of the expressed saliva and entrained organic material or a portion thereof from the receptacle.

The device for the recovery of saliva according to the invention enables one to obtain a saliva sample suitable for use in an 'on the spot', rapid immunoassay with a minimum of sample manipulation following collection thereof.

In one embodiment, the walls of the receptacle are flexible and allow for compression of the saliva collection device.

In an alternative embodiment, the receptacle is provided with a piston arrangement for compression of the saliva collection device.

Suitably, the receptacle and piston arrangement are provided with co-operating threaded portions, such that the saliva and entrained 5 material is expressed by screwing the piston into the receptacle.

Preferably, the receptacle is cylindrical in shape, with an open end for inserting the saliva collection device and a closed end having an aperture for expression of the saliva. The piston arrangement is inserted through the open end in use and compresses the saliva collection device towards the closed end.

Further, preferably, the diameter of the cross section of the cylinder increases stepwise at some point along the axis of the receptacle from the closed end to the open end thereof. The stepwise increase may be an abrupt increase or an angled or curved increase.

The stepwise increase results in the cylinder having a variable crosssection along its length. The piston arrangement has a cylindrical shape such that the leading end of the piston is a snug fit in the interior of the receptacle at the narrowest part thereof; a threaded portion of the piston arrangement cooperates with a complementary threaded portion 20 provided on the interior of the receptacle at the widest part thereof.

Since the piston arrangement operates by converting the torque due to screwing the parts together into a compressive force at the leading end, a greater efficiency is achieved by reducing the area of the leading end, since the pressure exerted, with a constant force, is 25 inversely proportional to the area over which the force acts.

Suitably, the piston arrangement and the receptacle are provided with roughened areas on their exterior surfaces to assist in screwing and unscrewing the parts. The roughened areas may, for example, be serrated, knurled, rippled or studded. Alternatively, the exterior shapes of the parts may be shaped to assist in twisting the parts relative to one another. An example of this would be where the receptacle, having a circular interior cross-section, has a hexagonal exterior crosssection; and the piston arrangement has two wings on the end opposite to the leading end, thereby allowing the user to grip and twist the piston arrangement while holding the receptacle tightly.

The threaded portions can each be raised or, alternatively, one threaded portion can be raised and the other sunk on or in the relevant surface, as appropriate.

The piston arrangement can be provided at its leading end with a sealing flange.

Alternatively, the piston arrangement can be provided at its leading edge with a sealing annular ring or O-ring.

Both of the abovementioned alternatives serve to prevent backflow of saliva along the piston arrangement from the leading end thereof.

Furthermore, means can be provided to maintain the compressible saliva collection device and the point of egress of expressed saliva in spaced-apart relationship.

Preferably, the egress of expressed material takes place through a dropper mechanism associated with the receptacle.

Alternatively, the egress of expressed material takes place through a dropper mechanism integral with the receptacle.

Suitably, the dropper mechanism is provided with a filter.

A suitable type of filter is one which comprises one or more layers of a filter material having a gradation of pore sizes in the range 0.5-5 μιη.

Further, preferably, the final layer through which the material percolates should have a pore size no greater than 1.0 gm.

Suitable materials for use in the filtration device include layers of glass, ceramic, wood, paper, etc., more especially glass.

With such an arrangement, filtrate can be transferred in droplets of a predetermined size, when desired.

The device for the recovery of saliva in accordance with the invention can be a device of the type disclosed in our Patent No. S58662, wherein the walls of the receptacle are flexible, but which does 10 not necessitate the use of a buffer for facilitating the release of the analyte of interest from the mass of absorbent material. In accordance with the invention, the use of a buffer is optional. The saliva and entrained material are trapped in the fibres of the absorbent fibrous material according to the invention and are released upon squeezing, 15 without the requirement for a releasing agent which would be required in the case of bound material. When a buffer is used the mass of absorbent material is inserted into the receptacle, which suitably has a tubular shape approximately 3 cm in length and with a diameter of 1.5 cm, resulting in saturation of the absorbent material by the buffer. By 20 squeezing the receptacle several times, the antibodies will equilibrate with the buffer. Suitably, the receptacle contains approximately 0.75 ml of phosphate buffered saline (PBS).

If the receptacle is provided with a dropper mechanism with an integral filter of the type disclosed in our Patent No. S58662, the 25 receptacle is inverted with the filtration device mounted at the free end and organic material such as immunoglobulin material, free of mucous, tissue and food debris resulting from the filtration process is obtained in a form ready to use in an immunoassay.

A dropper mechanism when used in association with the 30 filtration device suitably provides drops of processed liquid of approximately 30-70 pl.

In such a device, the flexible receptacle is preferably formed of a flexible plastics material.

The receptacle can also suitably be provided with a cap or other closing means.

The device for the recovery of saliva in accordance with the invention is suitably integral with an assay card for the detection of an analyte by bi-directional lateral chromatography. Assay card systems for the detection of an analyte by bi-directional lateral chromatography are the subject of U.S. Patent No. 5,006,474.

Alternatively, the device for the recovery of saliva in accordance with the invention is suitably integral with an assay card for the detection of an analyte by sequential activation of immobilized reagents. Such systems for the detection of an analyte by sequential activation of immobilised reagents are the subject of International Patent Publication WO 88/08534.

When the device for the recovery of saliva is of the type which is provided with a piston arrangement, the piston suitably has a hollow interior in which the saliva collection device can be stored prior to use. The hollow interior may be open or it may be sealed with a snap-off cap which is removed prior to use. The snap-off cap portion is suitably made of polyethylene.

The invention also provides a kit-of-parts comprising a device for the collection of saliva as hereinabove described and a device for the recovery of saliva as hereinabove described. Such a kit-of-parts provides apparatus which allows one to collect saliva from the oral cavity in sufficient amounts and in a form for direct use in an immunoassay, without a requirement for the usual laboratory instrumentation for the recovery and any processing of the saliva once collected, as herein described.

Saliva collected and recovered with the apparatus in accordance with the invention can be assayed by conventional methods with or without modifications, as required. Such modifications are minor. For example, a slightly more concentrated enzyme conjugate reagent may be required than would be used in a corresponding assay carried out on blood. Other modifications involve the use of an increased volume of saliva relative to serum, a decreased diluent volume and a lowering of the optical density cutoff to 70% of the serum value (see Frerichs R.R., et al. (1992) The Lancet, Vol. 340, Dec. 19/26, 1496-1499).

The Ig levels recovered are found to be high enough to be detectable by currently available assays. For example, many of the standard kits for testing HIV in serum can, with minor adjustments, be used for HIV testing on saliva. Such assays include Abbott HIVAB HIV-1 EIA and Abbott TestPack HIV-1 HIV-2 Kit (Abbott Laboratories Inc.) and HIV-1 Western Blot Kit (Biotech/Du Pont).

It will be appreciated that the basic assay will normally be an enzyme immunoassay.

The invention will be further illustrated by the following description of embodiments thereof given by way of example only with 20 reference to the accompanying drawings in which: Fig. 1 is an exploded schematic representation of a first embodiment of a device according to the invention for the recovery of saliva from an absorbent, compressible saliva collection device; Fig. 2 is an exploded schematic representation of a second embodiment of a device according to the invention for the recovery of saliva from an absorbent, compressible saliva collection device; Fig. 3 is a schematic representation of a device according to the invention for collection of saliva; Fig. 4 is an exploded schematic representation of a third embodiment of a device according to the invention for the recovery of saliva from an absorbent, compressible saliva collection device; Fig. 5 is a plan view of one part of the device of Fig. 4; and Fig. 6 is an exploded schematic representation of a fourth embodiment of a device according to the invention for the recovery of saliva from an absorbent, compressible saliva collection device.

Referring to Fig. 1, there is indicated generally at 10, a device for the recovery of saliva from an absorbent compressible ball of rayon fibres (not shown), which has been used to collect saliva in the manner hereinabove described. The device 10 is in two parts, namely a receptacle 11 in which the rayon ball is inserted following saliva collection and part 12 receivable in the receptacle 11. The receptacle 11 has at least a partial circumferentially extending thread 13 on its inner surface which is engageable with a cooperating thread 14 on the part 12. The receptacle 11 is provided with a dropper mechanism 15 at its end 16 remote from the open end 17. The rayon ball, which has been used to collect saliva, is inserted in the receptacle 11 and then the part 12 is screwed into the receptacle 11 so as to compress the ball to express the collected saliva, which in turn is expressed through the dropper mechanism 15 for use in an immunoassay.

Part 12 has a hollow interior 18 within which the rayon ball can be accommodated prior to use.

Referring to Fig. 2, there is indicated generally at 20, a device for the processing of collected saliva. The device 20 comprises a tubular receptacle 21, 3 cm long and 1.5 cm in diameter and is made of a flexible plastics material. The receptacle 21 receives at its open end 22, a filtration device 23 with an integral dropper mechanism 24. The filtration device 23 can be inter-engageable with the receptacle 21 in known manner and in such a way that the device is sealed against any egress of the sample when the device 20 is in an inverted mode, other than through the filtration device 23 and the associated dropper mechanism 24. The filtration device 23 in the engaged position abuts 5 an internal rib 25 provided on the receptacle 21.

Referring to Fig. 3, there is indicated generally at 26, a saliva collection device having an absorbent pad 27 of rayon material mounted on a plastics handle 28. The absorbent pad 27 is 1.5 cm long and 1.0 cm in diameter. The handle 28 is 6 cm long is provided with a 10 weakened line 29 adjacent the absorbent pad 27.

In use, the device 26 is used to collect a sample of saliva on the absorbent pad 27 from the oral cavity of a patient as hereinabove described.

The device 26 is used to transfer a collected sample to the device 15 20 which contains an amount of a buffer such as PBS, suitably 0.75 ml, at pH 7.2. The device 26 is inserted into the receptacle 21 to an extent such that the weakened line 29 is adjacent the upper edge thereof, whereupon the handle 28 is broken off by a snapping action and discarded. The filtration device 23 and integral dropper mechanism 24 20 is attached to the device 20 and the walls of the device 20 are squeezed so as to facilitate release of bound antibody into the PBS buffer. The device 20 is then inverted, whereupon the contents of the device percolate through filtration device 23, assisted by further squeezing of the tubular body 21. The filtration device 23 has a number of layers of 25 a filter material (not shown) as hereinabove described with graded pore sizes which retain mucous, tissue and food debris contained in saliva while permitting immunoglobulins to pass therethrough into the dropper mechanism 24 for collection. Droplets of filtrate are collected from the dropper mechanism 24 for use in an immunoassay.

Referring to Fig. 4, there is indicated generally at 30, a device for the recovery of saliva from an absorbent compressible ball of rayon fibres (not shown), which has been used to collect saliva in the manner hereinabove described. The device is in two parts, namely a receptacle 31 in which the rayon ball is inserted following saliva collection and part 32, which is a piston arrangement, receivable in the receptacle 31. The receptacle 31 has at least a partial circumferentially extending thread 33 on its inner surface which is engageable with a cooperating thread 34 on the part 32. A circumferentially extending sealing flange 35 is provided at the leading end 36 of part 32. The receptacle 31 is provided with a dropper mechanism 37 at its end 38 remote from the open end 39. The rayon ball, which has been used to collect saliva, is inserted in the receptacle 31 and then the part 32 is screwed into the receptacle 31 so as to compress the ball to express the collected saliva, which is then expressed through the dropper mechanism 37 for use in an immunoassay. The sealing flange 35 cooperates with the wall 40 of receptacle 31, in use, to assist in preventing backwise flow of the saliva towards the open end 39.

Referring to Fig. 5, there is shown a plan view of the receptacle 31 shown in Fig. 4. A plurality of raised ridges 41 extend across the inner surface 42 of the end 38. The ridges 41 prevent the possibility of the dropper mechanism 37 becoming blocked by the compressed rayon ball in use.

Referring to Fig. 6, there is indicated generally at 50, a device for the recovery of saliva similar to the device of Fig. 4. The device 50 has a receptacle 51 with a substantially cylindrical form, the diameter of which increases stepwise between end 52, having an integral dropper mechanism 53, and open end 54. The stepwise increase in diameter occurs over a short region which has the form of an angled slope 55.

A piston arrangement 56 has a cylindrical shape suitable to snugly fit the interior of the receptacle 51, and leading end 57 of the piston arrangement 56 is provided with a nitrile O-ring 58 which ensures a tight seal between the leading end 57 of the piston arrangement 56 and the receptacle 51. The piston arrangement 56 has a raised thread 59 complementary to a sunken thread 60 in the interior of the receptacle 51.

Both the receptacle 51 and the piston arrangement 56 are provided with roughened areas 61,62 on their exterior surfaces which assist in screwing and unscrewing the receptacle parts. The roughened areas 61,62 are serrations moulded into the receptacle 51 and piston arrangement 56, respectively.

The piston arrangement 56 is provided with a compartment 63 which is adapted to store a rayon ball 64 before use. The compartment is hygenically sealable with a snap-fit polyethylene cap 65 provided with a protruding tab 66 which facilitates the removal of the cap 65.

* * * * Example Saliva was collected from 25 HIV positive patients and 5 HIV negative controls using a rayon saliva collection device according to the invention. The saliva samples collected were tested for HIV using the SalivaCard (SalivaCard is a Trade Mark) HIV 1/2 test (Trinity Biotech Pic, Dublin, Ireland). Anti-HIV antibodies were detected in the saliva of all 25 HIV positive patients and no non-specific antibody was detected in the 5 negative controls.

* * * * The apparatus according to the invention is particularly suitable for use by hospital emergency rooms, clinics, medical and dental surgeries, and additionally in settings where HIV testing has become routine, such as in screening armed forces personnel, prisoners, insurance applications and for assessing immigrants.

Claims (5)

1. A device for the collection of saliva from the oral cavity, comprising a mass of saliva absorbing fibrous material having substantially no binding affinity for organic material contained in absorbed saliva, such that expression of saliva from the mass results in substantially all of the protein material being recoverable therefrom.

2. A device for the recovery of saliva from an absorbent, compressible saliva collection device, comprising a receptacle for the saliva collection device and means for compressing the saliva collection device to express saliva and entrained organic material therefrom and to cause egress of the expressed saliva and entrained organic material or a portion thereof from the receptacle.

3. A device according to Claim 2, wherein the device is provided with a piston arrangement for compression of the saliva collection device, and wherein the receptacle and piston arrangement are provided with co-operating threaded portions, such that the saliva and entrained material is expressed by screwing the piston into the receptacle.

4. A kit-of-parts comprising a device according to Claim 1 for the collection of saliva and a device for the recovery of saliva according to Claim 2 or 3.

5. A kit-of-parts according to Claim 4, substantially as hereinbefore described with particular reference to the accompanying drawings.