lab equipment

What is the supernatant of a centrifuged sample?

Referees to the fluid portion of the spun sample

Define specific gravity

The density or weight of a known volume of a fluid compared with an equal volume of distilled water

Why is it important to be able to assess the specific gravity of urine?

Gives an indication of the kidney’s ability to concentrate the urine (diseased kidneys will have dilute urine)

What is the purpose of the centrifuge?

Separate cells from fluid (blood cells from serum), concentrate or pack down material (red blood cells in a microhematocrit tube), portion or separate materials with particles of different sizes (parasites in a fecal sample)

Do all samples spin at the same rate of speed?

No

Why is it essential to counterbalance our centrifuge prior to operation?

Damage to the unit, samples will not spin properly therefore testing may be inaccurate

What do the initials PCV refer to?

Packed cell volume

Do we use whole blood or serum to perform a PCV?

Whole blood

What does a PCV tell us?

The hematocrit or PCV is a method of evaluating the percentage of whole blood that is composed of red blood cells

What does the prefix “oto” refer to?

Refers to the eye

What does the prefix “opthalm” refer to?

Refers to the eye

What is a transilluminator?

A single light source with an angled head. May or may not have a removable cobalt blue filter, used along with fluorescein stain to check for corneal abrasions. Some techs use this piece of equipment instead of a laryngoscope to illuminate the back of the throat when introducing the endotracheal tube during induction

Why might the clinician perform a schirmer tear test? What is the normal response in a dog?

Evaluates the tear production of the eye. Some conditions such as keratoconjunctivitis sicca (dry eye) are indicated by a lack of adequate tear production. This test should be done before any other testing with the eye to minimize irritation and reduce extra tear production. Normal response in dogs and cats is 10-25mm/min

Define canthus

The angular junction of the eyelids at either corner of the eyes

Define conjunctiva

The delicate membrane lining the eyelids and covering parts of the eyeball

Fluorescein stains are used to evaluate what?

Used to stain the cornea to evaluate corneal ulcers or abrasions, as well as the patency of the nasolacrimal ducts. Once the dye has washed over the surface of the eye it will adhere to any defects. The eye is then viewed in a darkened exam room with the use of a cobalt blue filter (transilluminator), the defects will glow. Using the filter to illuminate the nares for the presence of stain will establish that the ducts are patent

Briefly describe the methodology of the fluorescein test

Remove one of the strips impregnated with the dye from the sterile package, place it aseptically inside a sterile 3 cc syringe. Attach a needle to the syringe and fill with sterile saline to release the dye. Have prepared a second syringe with sterile saline only detach the needle. Detach the needle from the syringe containing the dye. The veterinarian will then gently irrigate the patient’s cornea with the dye solution. Once the entire cornea has been flushed, the veterinarian will then rinse the eye with sterile saline before examining for defects. An alternative method of staining the eye is to hold the stained tip of the fluorescein strip above the eye and wash the strip with sterile saline, flushing the stain onto the eye (more difficult to control the flow with this method)

What is a refractometer used for?

A handheld instrument intended to measure the concentration of solutions. Works by utilizing the refractive index of the material being measured, a system of lenses and prisms. Used to measure the specific gravity of urine, which gives an indication of the kidney’s ability to concentrate the urine (diseased kidneys will have dilute urine). Also used to measure the amount of protein a sample of plasma (Microhematocrit section)

What are some limitations of the urine reagent strips?

The pH and specific gravity are not generally thought to be accurate, therefore mechanical means of measurement are preferable (refractometer and pH meter)

Why is urinary pH important?

Evaluate for the presence of crystals, uroliths or a UTI

Describe why the clinician may use a fungassay — what is it testing for?

Used to culture (grow) dermatophytic fungi (ringworm). Medium in vial or tray is formulated to produce a red colour in the presences of growing dermatophytes. When incubated at room temperature, the colour change will be evident in 1-10 days

Describe what a woods lamp is and what it is used for. What are the limitations?

Hand held unit with a black light source and a magnifying glass. Used to examine the hair coat of patients suspected of having a dermatophyte infection (ringworm). Depending on the species of fungal growth, the spores will fluoresce under the black light. A positive wood’s lamp test should be confirmed by a fungassay test, limitations are that other materials, such as fiber and debris will also glow

Blood chemistry testing

Sample of blood is collected from patient by the technician, placed into a red top or serum separator blood tube and allowed to clot. Once clot has formed, the sample is spun down, the resultant serum is then used to analyze for some or all of the blood chemistry parameters

Albumin (ALB)

A protein produced by the liver, reduced levels of this may indicate chronic liver or kidney disease, or parasites such as hookworms

Alanine Aminotransferase (ALT)

Elevated levels of this enzyme may indicate liver disease

Alkaline Phosphate (ALKP)

An enzyme produced by the biliary tract in the liver, elevated levels may indicate liver disease or other disease processes such as Cushing’s

Amylase (AMYL)

An enzyme produced and secreted by the pancreas to aid in the digestive process, elevated levels may indicate liver disease or pancreatic inflammation

Urea

A waste produce produced by the liver and excreted from the body by the kidneys, an important indicator of kidney function

Calcium (Ca)

Increased levels of this mineral may indicate the presence of certain types of tumours diseases of the parathyroid gland or kidney

Cholesterol (CHOL)

Elevated levels may point to a number of different conditions such as hypothyroidism

Creatinine (CREA)

By-product of muscle metabolism, excreted by the kidneys, elevated levels may indicate kidney disease, urinary obstruction or muscle trauma

Blood glucose (BG)

Hyperglycemia or high levels in the blood may indicate diabetes, hypoglycemia or low levels may indicate liver disease

Fructosamine (fru)

Measures the average level of glucose control over the past few weeks

Phosphorus (PHOS)

Elevated levels of this mineral may indicate kidney disease

Total bilirubin (TBIL)

Secreted by the liver into the intestines, elevated levels may help to diagnose bile duct abnormalities

Total protein (TP)

Elevated protein levels in the blood may indicate a number of disease or conditions such as dehydration

Electrolytes (sodium, potassium, chloride)

Chemical substances present in the body, the balance or levels of these chemicals are essential for the function of all the body’s tissues and organs

Pancreatic lipase

An enzyme, elevated levels may indicate acute or chronic pancreatitis

SDMA

An increase indicated decreased kidney function, which can occur as a result of acute kidney injury, chronic kidney disease (CKD), or both. Much more sensitive test than urea and creatinine