Veterinary Practice Laboratory General Laboratory Equipment Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

In-House Veterinary Laboratories A variety of equipment is need in an in-house veterinary laboratory Factors that affect equipment needs Size of the practice Minimal equipment needs Microscope Refractometer Microhematocrit centrifuge Clinical centrifuge Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

In-House Veterinary Laboratories (cont.) Additional needs Blood chemistry analyzers Cell counters Water baths Incubators Test tubes Pipettes Aliquot mixers Heat blocks Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Test Tubes Glass or plastic Many sizes Microhematocrit Larger tubes Packed Cell Volume Larger tubes Blood collection Color coded Conical Tubes Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Centrifuges Vital instrument Separates substances of different densities Spins at high speed Heavier component pushed to the bottom of tube Sediment Liquid components above Supernatant Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Centrifuges (cont.) Microhematocrit centrifuge Clinical centrifuges Holds capillary tubes Clinical centrifuges Horizontal or swing arm Angled Designed for both hematocrit tubes and centrifuge tubes Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Swing Arm Centrifuges Tube holders swing out when in motion Disadvantages Heat build up at excessive speeds Damage specimens Mixing of sediment and supernatant when stops and reverts to vertical position Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Angled Centrifuge Fixed tube at about 52 degrees Higher speeds than swing arm Usually only one tube size Adapter for smaller tubes This centrifuge is designed for smaller tubes. Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Balancing Centrifuges Tubes must be counter balanced Same weight tube opposite Water filled Avoids Wobbling No liquid forced from the tubes Damage to the instrument Clean immediately if spills occur Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Routine Maintenance Follow manufacturer guidelines Check lubrication of bearings Check brushes Confirm timing Check speed Tachometer Prevents costly breakdowns Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Centrifuging Specimens Follow guidelines Too long or fast can result in Ruptured cells Changes in morphology Too slow or short of time Not complete separation Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Refractometer a.k.a. ‒ total solids meter Measures the refractive index of a solution Bending of light rays as they pass through from one medium to another with a different optical density. Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Refractometer (cont.) Measure the degree of refraction The function of the concentration of solid material in the medium Calibrated to Zero Distilled water between 60° and 100° F Measures Specific gravity of urine and other fluids Protein concentration of plasma (g/dL) Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Refractometer (cont.) A built in prism and scale Read at the light-dark interface Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Care and Maintenance Cleaned after each use Calibrate regularly Prism cover and glass wiped with lens tissue Follow manufacturers guidelines Calibrate regularly Adjusted by turning the adjusting screw Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Use of Refractometer Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Pipettes Most tests kits and analyzers come with pipettes Most commonly used Transfer Graduated TD pipettes To deliver large amounts Either TD or “TD with blowout” TC pipettes To contain Microliter amounts Use size closest to volume needed Transfer pipettes are used when critical volume measurements are not needed. These pipettes may be plastic or glass, and some can deliver volumes by drops. Graduated pipettes may contain a single volume designation or have multiple gradations. Pipettes with single gradations are referred to as volumetric pipettes and are the most accurate of the measuring pipettes. It is important that the pipette be used correctly to ensure that the desired volume is measured. Always hold the pipette vertically, not tipped to the side. Larger volumetric pipettes are usually designated as TD pipettes, which means that the pipette is designed “to deliver” the specific volume. A small amount of liquid should remain in the tip of the pipette after the volume has been delivered. Volumetric pipettes that have been designed to deliver microliter volumes are designated as TC pipettes, which means that the pipette is designed “to contain” the specified volume. These pipettes must only be used to add specified volumes of substances to other liquids. The pipette then must be rinsed with the other liquid to deliver the specified volume accurately. The small volume of fluid left in the tip of the pipette is then blown out of the pipette. Pipettes that contain multiple gradations are marked as either “TD” or “TD with blow out,” depending on whether the fluid remaining in the tip of the pipette should remain or be blown out. TD with blow out pipettes usually contain a double-etched or frosted band at the top. The pipette chosen for a specific application should always be the one that is the most accurate and that measures volumes closest to the volume needed. For example, a 1-mL pipette rather than a 5-mL pipette should be chosen if the volume needed is 0.8 mL. Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Incubators Microbiology Larger facilities 37° C best for incubating pathogenic bacteria Fitted with a thermometer inside the chamber May have built in humidity control If not a small dish of water should be added Larger facilities Control CO2 and O2 levels as well Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Incubator Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Water Baths/Heat Blocks Some assays, coagulation test and blood banking procedures require heat Constant temperature of 37° C Types Simple water bath Circulating water bath Waterless bead bath Heat blocks One tube size Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Miscellaneous Equipment Slide dryers Coffee mug heaters Aliquot mixer – Rockers Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Summary Test tubes Centrifuges Refractometers Pipettes Incubators Water baths Miscellaneous Equipment Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.