WO2001051909A1

WO2001051909A1 - Method and apparatus for automatic tissue staining

Info

Publication number: WO2001051909A1
Application number: PCT/US2001/000512
Authority: WO
Inventors: Ken K. Tseung; Glenn Takayama; Norman K. Rhett; Mark V. Corl
Original assignee: Lab Vision Corporation
Priority date: 2000-01-14
Filing date: 2001-01-08
Publication date: 2001-07-19
Also published as: AU2001226345A1; JP5189721B2; EP1247084B1; ES2282227T3; DE60126910D1; CA2396805C; EP1247084A1; CN1236297C; JP2013040974A; JP5444443B2; US6746851B1; CN1404573A; DK1247084T3; ATE355513T1; CA2396805A1; JP2003519791A; DE60126910T2

Abstract

A method and apparatus for specimen slide (710) preparation is disclosed. The method and apparatus of the present invention uses slide trays (700) that have receptacles for at least one specimen slide (710) and an associated reagent park (720). The specimen slide (710) and/or reagent pack (720) includes an identifier (420) that specifies a particular slide preparation protocol that should be followed. The method and apparatus reads the identifier (420) to determine the particular slide preparation protocol and then prepares the specimen slide according to the particular slide preparation protocol. The apparatus may obtain some or all of the reagents needed for the particular slide preparation protocol from the reagent pack (400).

Description

METHOD AND APPARATUS FOR AUTOMATIC TISSUE STAINING

Field of the Invention

The present invention relates to the field of medical lab

equipment. In particular the present invention discloses a fully automated

system for staining tissue specimens and cell preparations.

Background of the Invention

A normal function of medical laboratories is to examine cells

and cell tissue under a microscope. The lack of contrast between individual

cells and the background matrix or between individual parts of cells can

make it difficult to examine cell and tissue preparations. To improve the

contrast, researchers have applied stains to cell and tissue specimens to be

examined. The stains are absorbed differently by the various structures in

cells such that the contrast between the different cell structures is

improved.

Staining tissue specimens is a nontrivial time consuming

process. Often a number of different staining and rinsing stages are

required. Each stage requires a specific amount of reagent or buffer and takes a specific amount of time. Thus, trained technicians are often

employed to perform such operations. Furthermore, hospitals and

laboratories must stain very large numbers of tissue specimens for patient

diagnoses. Thus, automated tissue staining systems have been developed.

By automating the process, expensive human labor is eliminated.

Furthermore, automatically staining specimens significantly reduces the

probability of an error occurring during the staining process.

To ensure that the proper staining procedures are followed,

most automatic staining systems require that the user carefully enter the

staining protocol and load the proper reagents. The complicated procedures

require user training before such devices can be operated effectively. It

would therefore be desirable to simplify the operation of an automatic

tissue-staining device.

Summary of the Invention

A method and apparatus for specimen slide preparation is

disclosed. The method and apparatus of the present invention uses slide

trays that have receptacles for at least one specimen slide and an

associated reagent pack. The specimen slide and/or reagent pack includes

an identifier that specifies a particular slide preparation protocol that should

be followed. The method and apparatus reads the identifier to determine

the particular slide preparation protocol and then prepares the specimen

slide according to the particular slide preparation protocol. The apparatus

may obtain some or all of the reagents needed for the particular slide

preparation protocol from the reagent pack. Other objects feature and advantages of present invention will

be apparent from the drawings and the detailed description that follows.

Brief Description of the Drawings

The objects, features, and advantages of the present invention

will be apparent to one skilled in the art, in view of the following detailed

description in which:

Figure 1 A illustrates a cut-away view of a first tiltable sink

assembly embodiment.

Figure 1 B illustrates the tiltable sink assembly of Figure 1 A

wherein the tiltable sink assembly is tilted to the right.

Figure 1 C illustrates the tiltable sink assembly of Figure 1 A

wherein the tiltable sink assembly is tilted to the left.

Figure 2A illustrates a cut-away view of a second tiltable sink

assembly embodiment.

Figure 2B illustrates the tiltable sink assembly of Figure 2A

wherein the tiltable sink assembly is tilted to the right.

Figure 2C illustrates the tiltable sink assembly of Figure 2A

wherein the tiltable sink assembly is tilted to the left.

Figure 3 illustrates a conceptual diagram of the internal fluid

flow components of the autostainer apparatus.

Figure 4a illustrates a first arrangement of a reagent pack for

the autostainer apparatus of the present invention.

Figure 4b illustrates a second arrangement of a reagent pack

for the autostainer apparatus of the present invention. Figure 5a illustrates a four well reagent pack or the autostainer

apparatus of the present invention.

Figure 5a illustrates a six well reagent pack or the autostainer

apparatus of the present invention.

Figure 5c illustrates an eight well reagent pack or the

autostainer apparatus of the present invention.

Figure 6a illustrates a first embodiment of bulk packaged

reagent packs.

Figure 6b illustrates a second embodiment of bulk packaged

reagent packs.

Figure 7a illustrates a front view of a combined slide and

reagent rack for preparing four slides.

Figure 7b illustrates a back view of a combined slide and

reagent rack for preparing four slides.

Figure 8A illustrates a flow diagram of the general operation of

the autostainer apparatus.

Figure 8B illustrates a flow diagram summary of the slide

protocol scheduling system of the autostainer control program.

Figure 9a through 9d illustrate a flow diagram describing the

details of adding a new slide to the Currently Scheduled Array (CSA).

Detailed Description of the Preferred Embodiment

A method and apparatus for automatically staining tissue

specimens is disclosed. In the following description, for purposes of

explanation, specific nomenclature is set forth to provide a thorough understanding of the present invention. However, it will be apparent to one

skilled in the art that these specific details are not required in order to

practice the present invention. For example, the present invention has been

described with reference to staining of tissue specimens. However, the

same techniques can easily be applied to other types of slide preparation

work.

The Autostainer Hardware

The present invention comprises advances in automated slide

staining. An example of an automatic slide staining apparatus can be found

the first figure of U.S. Patent 5,839,091 , issued November 1 7, 1 998, and

entitled "Method and apparatus for automatic tissue staining" which is

hereby incorporated by reference in its entirety. An autostainer system is

used for staining tissue specimens that are placed onto glass slides. The

present invention uses several different slide racks wherein each slide rack

holds one or more slides. In one embodiment, there are six slide racks and

each slide rack is capable of holding four slides such that the autostainer

can prepare twenty-four different slides simultaneously.

An autostainer uses a robotic delivery system that delivers bulk

reagents, small supply reagents, buffer solutions, and air to the glass slides.

The robotic delivery system is controlled by a computer system. The

computer system executes an autostainer control program that sends

control commands to control the robotic delivery system. In one

embodiment, the robotic delivery system of the autostainer consists of an

X-axis mechanism, a Y-axis mechanism, and a Z head as illustrated in U.S. Patent 5,839,091 . The Z head has a Bulk fluid dispensing tube for

dispensing a few selected bulk reagents and buffer rinse solution, an air

blade to blow air onto slides, and a syringe probe for picking up reagents

that will be placed onto the glass slides.

To prevent contamination, the syringe probe is cleaned in a

reagent probe wash bin between the uses of different reagents. The wash

bin has three different receptacles that are used in three stages. The first

hole is used to rinse the inside of the probe by forcing buffer rinse solution

through the inside of probe and down into a first drain receptacle. The

second receptacle is used to clean the outside of the probe by forcing buffer

rinse solution through the inside of probe while the probe is in the tightly

confined second receptacle such that the buffer solution is force upward on

the outside of the probe. Finally, the probe is placed into a third receptacle

and air is forced through the probe to clean out the buffer rinse solution.

Beneath the slide racks of the autostainer is a sink assembly.

The sink assembly catches the reagents and buffer rinse solution that drip

off the slides. Figure 1 A illustrates a cut-away top view of a first

embodiment of a sink assembly. As illustrated in Figure 1 A, a tiltable sink

21 0 sits beneath a support bracket 205 for the slide racks (not shown).

The tiltable sink 21 0 may be tilted left or right using a tilt mechanism 220.

When the tiltable sink 210 is tilted down on the right side as illustrate in

Figure 1 B, all the liquid waste spilling off the slides will drain out of drain

hole 231 on the right side, through corrugated tubing 241 and drain pipe

251 , and finally to a waste line #1 (not shown). Similarly, when the tiltable sink 210 is tilted down on the left side as illustrated in Figure 1 C, all the

liquid waste will drain out of drain hole 232, through corrugated tubing 242

and drain pipe 252, and finally to a waste line #2 (not shown). As

illustrated in Figures 1 A through 1 C, the two waste lines conveniently exit

the device at the same location.

With the tiltable sink system of the present invention, the

present invention can send different types of down different waste lines

such that a first waste line may be used to remove nonhazardous waste

and the other waste line may be used to remove hazardous waste. The non

hazardous waste line may simply be connected to a sewage drain pipe. The

hazardous waste line should be connected to hazardous waste container

that is disposed of appropriately.

Figures 2A through 2C illustrate an alternate embodiment of a

tiltable sink system. Referring to Figures 2A through 2C, the drain line

travels straight down such that the two waste lines exit at different

locations.

Fluid Flow components

Several other components are also located inside the

autostainer. Figure 3 illustrates a conceptual diagram the fluid flow

components of the autostainer. Referring to Figure 3, three different output

devices located on the Z-Head assembly of the autostainer deliver air or

fluid to the slides.

A first output device is the bulk fluid dispensing tube 321 .

The bulk fluid dispensing tube 321 is used to deliver relatively large quantities of fluid to slides. The bulk fluid dispensing tube 321 may

dispense buffer solution from buffer supply 301 or reagents from internal

bulk reagent supplies 302, 303, and 304. The particular fluid dispensed is

selected by 8-way distribution valve 331 .

A second output device is the reagent-dispensing probe 322.

The reagent-dispensing probe 322 draws in specific reagents using syringe

pump 340 and then dispenses drawn-in reagents onto specific slides. To

prevent contamination of the reagent-dispensing probe 322 from different

reagents, the autostainer cleans the reagent-dispensing probe 322.

Specifically, the autostainer first flushes the reagent dispensing probe 322

by forcing buffer solution through the reagent dispensing probe 322 using

three-way valve 332. Then, the autostainer dries the reagent dispensing

probe 322 by forcing air through the reagent dispensing probe 322 using

three-way valve 333.

The third output device is air blade 323. Air blade 323 is used

to dry off slides and blow away extra reagents.

Autostainer Reagent Packs

To simplify operation, the present invention introduces an

autostainer system with greatly simplified operation. To use the autostainer

system of the present invention, a user simply adds a set of slides where

each slide is accompanied by a specific reagent pack that contains the

reagents needed for a specific slide preparation protocol. The reagent pack

further includes information that identifies the slide preparation protocol to

be performed. Figure 4a illustrates a first embodiment of a reagent pack that

may be used with the autostainer system of the present invention. As

illustrated in Figure 4a, the reagent pack comprises a container with a set of

wells (401 to 406 in Figure 4a) for storing reagents. The container is

sealed using a cover 41 0. The cover 410 may include an identification

mark such as barcode 41 1 to identify the slide preparation protocol to be

performed. The cover 41 0 protects and retains the reagents in the wells

401 to 406, yet the reagent dispensing probe 322 is able to puncture and

access the reagents as needed.

The cover 410 may further include a second barcode

identification sticker 420. The barcode identification sticker 420 can be

placed directly onto a slide to be performed such that the autostainer will

automatically know the slide preparation protocol to be performed.

Figure 4b illustrates an alternate embodiment of a reagent pack

490. In the alternate embodiment of Figure 4b, the identifiers 431 and 441

have been placed parallel to the line of wells 401 to 406. In yet another

embodiment (not shown), a tiltable sink is created with four drain holes

with one hole at each corner. In such an embodiment, four different waste

systems may be used.

The autostainer system of the present invention is capable of

handling many different slide preparation protocols that require different

numbers of reagents. Figures 5a, 5b, and 5c illustrate different sized

reagent packs for different protocols. Figure 5a illustrates a simply four

reagent pack for simple slide preparations. Figure 5b illustrates the six- reagent pack of Figure 4a. Figure 5c illustrates an eight-reagent pack for

complex slide preparation protocols.

The autostainer will be used to perform large numbers of slide

preparations. Each slide preparation requires a reagent pack. To simplify

purchasing, reagent packs may be purchased in bulk packages. Figure 6a

illustrates one possible bulk package where several reagent packs are sold

in a perforated two-dimensional matrix of individual reagent packs. Figure

6b illustrates an alternate bulk package where several reagent packs are

sold as a strip of connected of individual reagent packs.

Autostainer Slide Racks

The slide racks for the autostainer of the present invention

have been designed for ease-of-use and maximum flexibility. Figure7a

illustrates a front view of one possible slide rack that may be used in the

autostainer of the present invention. The slide rack 700 has four slide

positions such that the slide rack 700 can hold four slides 710. Other slide

rack embodiments may hold more or less than four slides. The slides may

be standard U.S. or international sized slides. The slide rack 700 further

includes four reagent positions for storing reagent packs 720 associated

with the adjacent slide positions. Figure 7b illustrates a back view of the

slide rack 700.

Autostainer Control and Programming

As stated in the previous section, the autostainer is controlled

by a computer system. In a present embodiment, the computer system is

based on a standard Personal Computer (PC) motherboard with a PCI bus. The computer system runs an autostainer control program to control the

operation of the autostainer.

The autostainer control program is a sophisticated control

program that implements many security, automatic slide protocol

programming, control, and logging features. To fully describe the

autostainer control program, this document will step through a sample use

of the autostainer.

User Loading

To operate the autostainer, a user loads slide trays (as

illustrated in Figures 7a and 7b) with slide specimens and associated

reagent packs. In one embodiment, the user simply places the proper

reagent pack in the reagent pack receptacle adjacent to the specimen slide

to be prepared. In another embodiment, the user places an associated

identifier on the frosted area of the specimen slide to be prepared. This can

be done by peeling off a barcode sticker 420 from the reagent pack 400

and placing it on the frosted area of the slide. By specifically labeling each

slide with the protocol to be performed, no error can be introduced by

accidentally placing the wrong reagent pack next to a specimen slide.

Slide Preparation Protocol Identification

After loading one or more slide trays, the user places the

loaded slide trays into the autostainer system. The user then instructs the

autostainer system to commence slide preparation by activating a "restart"

input. If the user has added very high priority slides to the autostainer, the

user may instead press a "ST AT" input to indicate that the new slides are very high priority. The autostainer system then commences operation by

first examining the loaded slides and reagent packs to determine the slide

preparation protocols that need to be performed. Specifically, the

autostainer system reads all the identifiers (on the slides and/or reagent

packs) and then consults a slide preparation protocol database that maps

the different identifiers on the reagent packs with the slide preparation

protocols to be performed.

The slide preparation protocol database may be periodically

updated by shipping media such as floppy disks or CD-ROMs that are

inserted into an appropriate drive on the autostainer. In one embodiment,

the autostainer system uses a network to automatically retrieve database

updates. This may be performed by having the autostainer coupled to a

telephone line with a modem such that the autostainer automatically calls

specific number to obtain slide preparation protocol database updates. In

an alternate embodiment, the autostainer may be coupled to the global

Internet such that the autostainer may connect to a server that stores the

most recent slide preparation protocol database information. In any of

these embodiments, the autostainer may also simultaneously receive

program updates such that the software that controls the autostainer may

be automatically updated.

Slide Staining Apparatus Operation

Once a user has loaded the autostaining apparatus, the user

may start staining run. Figure 8A illustrates the general procedure of

operating the autostaining device. Referring to Figure 8A, the user loads a slide/stain tray at step 801 . The user then starts the apparatus by pressing

the restart or stat button at step 802. The autostaining apparatus then

examines all the slides to determine the slide protocols that must be

performed at step 803. The system may compare a barcode sticker 402 on

a slide with a barcode 41 1 on the cover 41 0 of an adjacent reagent pack to

ensure that the proper reagent pack has been placed next to each slide.

After examining all the slides and reagent packs, the system creates a

staining schedule. Details on how the staining apparatus creates the

staining schedule will be presented in the following section.

After calculating a staining schedule, the autostaining

apparatus beings to process slides according to a created staining schedule.

The system continues the staining operations until one of the conditions of

step 805 are detected (or an error occurs). Specifically, step 805

determines if the staining run is completely done, the staining run is partially

done, or if the user has pressed the pause button.

If the staining run is partially done, then the system proceeds

to step 807 where the user is informed of the completed slide(s). The user

may wish to remove those slides such that they can be examined.

If the user pressed the pause button, then the system

temporarily ceases operation. The user may then load additional slide trays

at step 801 . The system remains paused as it waits for the user to press

the restart or stat button. Once the user has pressed either the restart or

stat button at step 802, the system proceeds to step 803 to create a new staining schedule. The system then resumes slide staining at step 804

using the new staining schedule.

Referring back to step 805, if the system is completely done

with the staining run, then the system may cease operation. As shown in

Figure 8A, a user may continually remove completed slide trays and add

new slide trays continually by only using the pause and restart/stat buttons.

Thus, the staining apparatus may be in continuous operation all day long.

Slide Preparation Scheduling

Once the slide preparation protocols that need to be performed

have been identified, the autostainer control program proceeds to calculate

the most efficient dispensing pattern for performing the desired slide

protocols.

Figure 8B illustrates a summary of how the autostainer control

program calculates the most efficient dispensing pattern. Referring to

Figure 8B, at step 810 the autostainer control program first determines if a

run was already in progress. If a run was already in progress, then the

autostainer control program adds the current slides into a scheduling table

at step 81 5. The scheduling table will be used to program the autostainer

control program.

Next, at step 820, the autostainer control program has the z-

head assembly scan all the slide positions to determine if any new slides

have been added or any existing slides have been taken away. If a slide

that had not yet completed its protocol was removed, the autostainer may

inform the user of the error and ask if the user wishes to place the slide back into the autostainer. When one or more new slides have been added,

the autostainer control program adds those slides into the current

scheduling table as stated in step 820 of Figure 8B. If the user designated

the new slides as "STAT", then those newly added slides are given top

priority.

After the autostainer control program has added the filled the

scheduling table, the autostainer control program proceeds to step 830 to

begin automatic programming. At step 830, the autostainer control

program first places the slides into a specific order. In one embodiment, the

autostainer control program orders the slides using this order:

1 . Highest priority slides (such as STAT slides).

2. Slides with the longest incubation time.

3. Numerical order.

The system then proceeds to re-order the slides using a well-

defined method. Figure 8B illustrates one possible method of ordering the

slides. Initially, the first slide from the order of step 830 defines the

currently scheduled array (CSA). The CSA defines a newly proposed slide

order. At step 845, the method selects the next unscheduled slide from the

scheduling table. That slide is then placed into the CSA as stated in step

850. At step 860, the method determines if the slide fit properly into the

current stage of the CSA. The method of determining if a slide "fits" into

the current stage of the CSA is fully defined in Figures 9a to 9d. If the slide

did not fit, the method proceeds to step 870 to determine if the control

program has tried to fit all the remaining unscheduled slides into the current stage. If there are unscheduled slides that the autostainer control program

has not attempted to put into the current stage, then the method proceeds

to step 873 to select an unscheduled slide with a different protocol. The

autostainer control program then returns to step 850 to attempt to add that

slide into the current stage.

If, at step 870, the autostainer control program is unable to fit

any unscheduled slide into the current stage, then the autostainer control

program move to the next stage of the current schedule array (CSA) as

stated in step 879. The autostainer control program then proceeds back to

step 845 to start placing slides into the new stage.

Referring back to step 860, after each new slide is added to

the CSA, the autostainer control program determines if all the slides have

been scheduled as stated in step 880. If all the slides have been scheduled,

the autostainer control program determines if it has created a slide-

processing schedule that is faster than the current best time. If the

autostainer control program determines that it created a slide-processing

schedule faster than the previous best time, then the autostainer control

program saves the newly created schedule as the best schedule at step

883. At step 890, the autostainer control program determines if it has tried

all the possible slide orders. If it has not, the autostainer control program

proceeds to step 895 where the autostainer control program changes the

slide order while maintaining the designated slide priority order. The

autostainer control program then proceeds back to step 840 to test a new

slide schedule. If, at step 890, the autostainer control program determines that it has tried every possible slide order (that maintains the slide priority

order), the autostainer control program returns the best schedule.

The foregoing has described a method and apparatus for

automatic tissue and cell preparation staining. It is contemplated that

changes and modifications may be made by one of ordinary skill in the art,

to the materials and arrangements of elements of the present invention

without departing from the scope of the invention.

What is claimed is:

Claims

1 . A method of operating an autostainer device, said method comprising

the steps of:

accepting a slide tray, said slide tray having at least one specimen slide and a reagent pack associated with said specimen slide, said reagent pack comprising a first identifier that specifies a particular slide preparation protocol; reading said first identifier from said reagent pack; and preparing said specimen slide according to said particular slide preparation protocol.

2. The method as claimed in claim 1 wherein said reagent pack is

associated with said specimen slide by being adjacent to said specimen

slide.

3. The method as claimed in claim 1 wherein said reagent pack is

associated with said specimen slide by having a second identifier on said

specimen slide that is the same as said first identifier.

4. The method as claimed in claim 1 wherein said reagent pack

comprises a set of wells, each well containing a reagent needed for said

particular slide preparation protocol.

5. The method as claimed in claim 1 wherein said reagent pack

comprises a peel-off identifier, said peel-off identifier for placement on said

specimen slide.

6. A method of operating an autostainer device, said method comprising

the steps of:

accepting a slide tray, said slide tray having at least one specimen slide and a reagent pack associated with said specimen slide, said specimen slide comprising a first identifier that specifies a particular slide preparation protocol for said specimen slide; reading said first identifier; and preparing said specimen slide according to said particular slide preparation protocol.

7. The method as claimed in claim 6 wherein said reagent pack is

associated with said specimen slide by being adjacent to said specimen

slide.

8. The method as claimed in claim 6 wherein said reagent pack is

associated with said specimen slide by having a second identifier that is the

same as said first identifier.

9. The method as claimed in claim 6 wherein said reagent pack

comprises a set of wells, each well containing a reagent needed for said

particular slide preparation protocol.

1 0. The method as claimed in claim 6 wherein said reagent pack

comprises a peel-off identifier containing said first identifier, said peel-off

identifier for placement on said specimen slide.

1 1 . An apparatus for staining specimen slides, said apparatus comprising:

more than one slide tray, said slide tray for holding more than one specimen slide; an automatic staining head assembly, said automatic staining head assembly for depositing reagents on said specimen slides, said automatic staining head assembly further comprising an input device for reading identifiers that specify slide preparation protocols to perform; a control system, said control system coupled to said automatic staining head assembly for controlling said automatic staining head assembly to prepare said specimen slides during a staining run; a pause input, said pause input for pausing said apparatus during said staining run; and a restart input, said restart input for restarting said apparatus after adding new specimen slides onto on of said slide trays; wherein said control system causes said automatic staining head assembly to read a new set of identifiers associated with said new specimen slides to add said new specimen slides to said staining run.

1 2. The apparatus as claimed in claim 1 1 wherein said apparatus further

comprises reagent packs.

1 3. The apparatus as claimed in claim 1 2 wherein each said reagent pack

comprises a set of wells, each well containing a reagent needed for said

particular slide preparation protocol.

14. The apparatus as claimed in claim 1 2 wherein said identifiers

comprise a barcode on each said reagent pack.

1 5. The apparatus as claimed in claim 1 1 wherein said identifiers

comprise a set of barcodes on said specimen slides.

1 6. The apparatus as claimed in claim 1 1 further comprising:

a STAT restart input, said STAT restart input for restarting said apparatus after adding new specimen slides onto on of said slide trays wherein said new specimen slides are given high priority;

1 7. A slide rack for a slide staining apparatus, said slide rack comprising:

a first receptacle for accepting a specimen slide; and a second receptacle for accepting a reagent pack, said reagent pack containing at least one reagent needed to prepare said specimen slide.

1 8. The slide rack as claimed in claim 1 7 further wherein said reagent

pack further comprises an identifier that identifies a slide preparation

protocol for said specimen slide.

1 9. The slide rack as claimed in claim 1 7 further wherein said first

receptacle and said second receptacle are adjacent to each other.

20. A reagent pack for a slide staining apparatus, said reagent pack

comprising:

a set of wells, said well containing reagents for a specific slide preparation protocol; and an identifier, said identifier associated with said slide preparation protocol.

21 . The reagent pack as claimed in claim 20 wherein said identifier

comprises a peel-off sticker for placement on an associated specimen slide.

22. The reagent pack as claimed in claim 20 further wherein said

identifier comprises a peel-off sticker for placement on an associated

specimen slide.

23. A slide staining apparatus, said apparatus comprising:

at least one slide rack for holding a slide specimen to be prepared; and a tiltable sink assembly, said tiltable sink assembly having a first drain hole on a first side such that liquid material drains through said first drain hole when tilted down on said first side, said tiltable sink assembly having a second drain hole on a second side such that liquid material drains through said second drain hole when tilted down on said second side.

24. The apparatus as claimed in claim 23 wherein said first drain hole is

coupled to a sewage system.

25. The apparatus as claimed in claim 23 wherein said second drain hole

is coupled to a hazardous waste container.

26. The apparatus as claimed in claim 23 wherein said second drain hole

is coupled to a corrugated tube.

7. An apparatus for staining specimen slides, said apparatus comprising:

at least one slide tray, said slide tray for holding at least one specimen slide and an associated reagent pack, said associated reagent pack having reagents needed for processing said specimen slide; and an automatic staining head assembly, said automatic staining head assembly for obtaining said reagents from said associated reagent pack and depositing reagents on said specimen slide.