Dr. Claude is completing a residency in small animal internal medicine at the University of Florida. She received her doctorate of veterinary medicine from the University of Minnesota, followed by a small animal rotating internship at Angell Animal Medical Center in Boston, Massachusetts. Her primary interests include hepatobiliary and hematologic disease.Read Articles Written by Riley Claude
Stuart A. Walton
BVSc, BScAgr, MANZCVS (SAIM), DACVIM
Dr. Walton is a clinical assistant professor in small animal internal medicine at the University of Florida. He earned his veterinary degree at the University of Queensland in Australia and has completed 2 internal medicine residencies; the first at Veterinary Specialist Services (Australia) and the second at Louisiana State University. His many interests include infectious and inflammatory diseases, immune-mediated disease, respiratory disease, and extracorporeal blood purification techniques.Read Articles Written by Stuart A. Walton
Despite the availability of new diagnostic tests, some older tests still provide valuable information that can be used to diagnose, monitor, and treat many conditions.
Although most are simple to perform, some require training to both perform and interpret. Costs vary, but most are inexpensive. The practicality and usefulness of these diagnostic tests should not be overlooked.
- The value of some older diagnostic tests is their simplicity, ease of use, and cost-effectiveness.
- Performing some tests may require experience and/or training.
- Many tests provide general, early diagnostic information; more specific follow-up testing may be required.
- Many test results are most useful when combined with patient signalment/history, clinical examination findings, and other diagnostic test results.
As we navigate the rapid development and transformation of veterinary medicine, diagnostic tests are continuously emerging and evolving. Although these newer tests can be valuable and relevant resources, they often provide a narrow spectrum of information attached to a sizable price tag. As newer diagnostic tests become available, many older, practical, and affordable tests may be overlooked. Performing and interpreting these diagnostics are critical skills as these tests can provide comprehensive diagnostic, monitoring, and treatment information. This article provides cost (BOX 1), indications, methods, and interpretation for several key practical and cost-effective diagnostic tests.
$$ = $50 to $75
$$$ = More than $75
Blood smears are a fundamental part of a complete blood count (CBC). Although smears are inexpensive, training is required to prepare good quality slides, analyze them, and interpret the findings (BOX 2, FIGURE 1). A well-prepared blood smear remains paramount for:
- Verifying and providing accurate differential cell counts
- Assessing morphologic abnormalities (e.g., red blood cells [RBCs], leukocytes/white blood cells [WBCs])
- Identifying hemoparasites, neoplastic cells, and cellular inclusions
- Prepare blood smears from gently mixed EDTA (ethylenediaminetetraacetic acid) and anticoagulated blood at room temperature.
- Use a microhematocrit tube to transfer a small drop of blood (4 mm) to 1 end of the microscope slide.
- Use the “wedge technique” to spread the drop of blood. A “spreader slide” is laid in front of the drop (30°–45° angle) and slowly slid backwards into the drop of blood. After the drop of blood smears along the slide edge, the spreader slide is smoothly and quickly slid forward with light pressure, creating a blood smear.
- Smeared blood closest to the initial drop of blood should be darker and should gradually become clearer across the smear.
- Smears should be 50%–66% of the slide length with a curved smooth monolayer edge.
- The angle of the spreader slide should be increased for blood from anemic patients and decreased for thicker blood samples.
- Place slides upright to dry (5–10 min) and then stain with Diff-Quik.
Materials needed: Microscope slides, Diff-Quik stain (Romanowsky stain variant), microscope with 4× to 100× objective lenses, immersion oil
Methods and interpretation: Evaluating blood smears requires a systematic approach. To assess the quality of the smear, the authors recommend initial evaluation under low magnification, followed by assessment of the density of RBCs and WBCs (10× to 20× objective). Slides are also assessed for rouleaux formation and/or agglutination. Under the same objective, the feathered edge is assessed for platelet clumps, microfilaria, or any large abnormal cells (e.g., blast cells, mast cells, macrophages).
To approximate hematocrit, monolayer examination of RBC apposition may be used. In anemic patients, RBCs are widely separated from one another; in nonanemic patients, RBCs are closely apposed (FIGURE 2). These estimates should be referenced against measured hematocrit or packed cell volume (PCV).
To approximate WBC counts under the 10× objective, count the number of WBCs in the monolayer (usually 18 to 50 cells). Each WBC corresponds to 330 cells/µL. For example, 13 WBCs/10× objective; 13 × 330 cells/µL = 4290 WBCs/µL. The number of cells per µL = (average no. cells/field) × (objective power).1
A more definitive assessment of RBCs, WBCs, and platelets can be performed under higher power (100× objective). More specifically, a manual differential cell count can be performed to verify hematology analyzer results, concurrently assessing morphology, density, and presence of inclusion bodies or parasites (TABLE 1, FIGURES 3 AND 4). At 100× magnification, a platelet count can also be performed. Platelets over several fields (5 to 10/field) are counted and then averaged. The average platelet number is then multiplied by 15 000 to 20 000 to estimate platelets/µL (FIGURE 3).
Packed Cell Volume/Total Protein
This test is underutilized in veterinary medicine. When performed and interpreted correctly, the test provides valuable information for disease diagnoses and assists clinicians with medically guided treatment.
Materials needed: Determining PCV requires microhematocrit tubes, clay sealer, a microcentrifuge, a refractometer, and a PCV reading tool.
Methods and interpretation: PCV should always be interpreted in conjunction with total protein and assessed with patient history, clinical examination findings, and other diagnostic test results when available (TABLE 2). Reference ranges are 37% to 55% for adult dogs (most breeds) and 30% to 45% for cats. PCV is lower in young animals (4 weeks; 24% to 34%) than in adult animals and gradually increases with maturity.1
Microhematocrit tubes also provide valuable information after blood is centrifuged and separated into layers.
- Assess the plasma color, which is normally clear and colorless (TABLE 3).
- Next, examine the buffy coat. The buffy coat consists of WBCs with a thin white layer of platelets on the top (FIGURE 5). If the bottom layer of the buffy coat is pink to red, it indicates presence of abnormal and immature RBCs. Buffy coat thickness is measured similarly to PCV; accurate measurements are difficult. The first 1% (0.01 L/L) is equivalent to 10 000 WBCs/µL (1 × 109 WBCs/L), and each additional 1% represents 20 000 WBCs/µL (2 × 109 WBCs/L).1
- Measure total proteins by using a refractometer. Reference total protein levels in dogs range from 5.9 to 7.8 and in cats from 5.9 to 7.5.2
Complete urinalysis results play a vital role in evaluating urinary tract health and provide valuable information about the systemic wellness of patients. Urinalysis should be interpreted in conjunction with patient history and physical examination findings and is indicated for any patient having blood collected for a CBC and serum chemistry. Likewise, urine should be analyzed for patients that are systemically ill or have renal disease.
Materials needed: Refractometer, urine dipstick, centrifuge, pipette or syringe, conical or red top tube, microscope slides, microscope with 4× to 100× objective lenses, and immersion oil
Methods and interpretation: Urine can be collected by free catch, catheterization, or cystocentesis. Recording both the method and time of collection is recommended as these factors may affect results. Early morning urine samples are considered best for evaluating tubular function, whereas late morning to early evening samples are best for microbial culture and assessing cellular morphology.3,4 To avoid temperature- and time-dependent effects on crystal formation, samples should be analyzed within 1 to 2 hours of collection3; if not analyzed during this window, samples should be refrigerated.
Assessment involves evaluation of physical characteristics, semiquantitative chemical analysis, and sediment.
- Color: Normal urine color is light yellow to amber but may be influenced by diet, medications, and hydration status.5 Abnormal urine colors, when observed, should be investigated to determine the underlying cause. Pigmenturia may be differentiated from hematuria by centrifugation.
- Clarity: Urine clarity is influenced by particulate matter, which is subjectively graded from clear to flocculent. Turbid urine samples should undergo sediment evaluation to determine the cause.
- Specific gravity: Urine specific gravity (USG) measures the solute concentration of urine, providing an estimate of the ability of the renal tubules to concentrate or dilute the glomerular filtrate.5,6 It should be interpreted in light of patient hydration status, electrolyte concentrations, blood urea nitrogen and creatinine concentrations, certain medications (e.g., diuretics, corticosteroids), and fluid therapy administration. USG obtained from a first morning urine sample can indicate optimum concentration ability but can vary up to 0.015 from day to day in healthy animals.7
Semiquantitative Chemical Analysis (pH, Blood, Glucose, Ketones, Bilirubin, and Protein)
Dry reagent strips are used in veterinary medicine to determine urine pH, protein, glucose, ketones, bilirubin/urobilinogen, and occult blood. Tests pads produce a colorimetric chemical reaction when interacting with specific substances in urine.8 Reagent strips are unreliable for measuring USG, WBCs, nitrite, and urobilinogen.9 Pigmented urine can interfere with test strip readings. Urine pH, a global estimate of acid–base status, may be affected by many renal and extrarenal factors (e.g., handling, diet, medications, bacterial infection, systemic illness).5,10 Glucosuria, when detected, should be assessed concurrently with serum glucose.11 Determining protein concentration by dipstick, which primarily detects albumin, is a good screening test for proteinuria. Results must be interpreted in light of USG, pH, and urine sediment examination.5 Negative reactions are usually reliable; samples with positive test reactions for patients with an inactive urine sediment should undergo quantitative confirmatory testing (i.e., urine protein:creatinine [UPC] ratio).
Sediment Evaluation (RBCs, WBCs, Organisms, Epithelial Cells, Crystals, and Casts)
Sediment provides definitive evidence of inflammation, infection, or hemorrhage within the urinary tract.5 Samples are centrifuged at low speed (1000 to 1500 rpm) for 5 minutes before most of the supernatant liquid is removed, leaving the sediment and a small volume (0.5 to 1 mL) of urine. The sample is then resuspended and 1 drop is placed on a microscope slide with a coverslip. Slides are analyzed at low power for crystals and casts and at high power for cells (RBCs, WBCs, transitional cells) and bacteria. Crystalluria is a common finding; certain crystals (e.g., amorphous, struvite) can be seen in healthy dogs.12 More information on slide preparation and analysis is available in the Today’s Veterinary Practice May/June 2014 article, Urinalysis in Companion Animals, Part 2: Evaluation of Urine Chemistry and Sediment.13
Targeted Urine Testing
Targeted urine testing includes the urinary corticoid:creatinine ratio (UCCR) and UPC ratio. Testing is minimally invasive and can provide valuable information for screening and diagnosing disease. It may also be used for monitoring disease progression or treatment response. Proper patient selection helps ensure the most useful and cost-effective information.
Materials needed: Clean container for collecting urine
Urinary Corticoid:Creatinine Ratio
UCCR is a valuable screening test that has been used for decades for patients suspected of having hyperadrenocorticism.14 The test provides an indirect, integrated measure of circulating corticoid production over time by measuring renal excretion of cortisol (free and conjugated). The test therefore eliminates rapid fluctuations in plasma concentrations of cortisol, which can lead to a false-positive diagnosis.15-17 This relatively inexpensive test is widely available to clinicians through commercial diagnostic laboratories.18,19 The test is used to screen for hyperadrenocorticism in dogs but may also have diagnostic value as a screening test for hypoadrenocorticism (sensitivity 97.2% to 100%, specificity 93.6% to 97.3%).14,16,18 It should not be used to monitor treatment of hyperadrenocorticism because it is not considered a reliable indicator of successful treatment.20-22 The test is advantageous over other screening tests because clients can collect urine from clinically healthy animals in a stress-free home environment. As a screening test for hyperadrenocorticism, UCCR sensitivity is high (75% to 95%), but specificity is poor (reportedly as low as 20%).17,18,23-29 The low specificity is attributed to increased corticoid release in stressed healthy dogs (e.g., during hospitalization) and dogs with nonadrenal-associated illness.28,29 Therefore, UCCR can help rule out hyperadrenocorticism but should not be used to establish a diagnosis.
UPC is another valuable urine test that measures the amount of protein loss through the kidneys. It can be valuable for diagnosing and staging disease as well as guiding clinical decisions and treatment response. UPC can also be a prognostic indicator; numerous studies have shown greater risk for death among patients with proteinuria.30 This test is recommended for patients with documented proteinuria or suspected proteinuria based on an underlying disease process. The magnitude of UPC elevation can also help identify the location of protein loss (tubular versus glomerular disease).30
Methods and interpretation: Because urine collected as a single sample, serial samples, or pooled samples yields similar results, single-sample collection may be preferred due to the ease of collection and analysis.31 This diagnostic test is available at reference laboratories and can also be performed in-clinic with some analyzers. UPC should always be performed in combination with urinalysis as abnormal urine sediment resulting from disease in the lower urinary tract can also increase the UPC (postrenal proteinuria).30
Because UPC fluctuates widely day to day, for a single UPC measurement to be considered significant, it must vary substantially. For a safe assumption that proteinuria has increased, single samples must differ by up to 40% in dogs and 90% in cats.30
A UPC of <0.2 is considered to be within normal range, with a UPC of 0.2 to 0.5 in dogs and 0.2 to 0.4 in cats considered to be borderline proteinuric. To investigate the underlying cause of proteinuria when the UPC is ≥2, additional diagnostics should be performed. UPC ratios of ≥0.5 (dogs) and ≥0.4 (cats) in stable patients should be monitored 2 to 3 times at 2- to 3-week intervals to determine if the proteinuria is progressing. For nonazotemic patients with a UPC ≥2, pathologic glomerular disease should be considered more likely. For patients with chronic kidney disease (i.e., azotemic patients) with UPCs ≥0.5 (dogs) and ≥0.4 (cats), further diagnostics should be performed to elucidate a cause for the proteinuria. When an underlying cause is identified, it should be treated.
Basal/resting cortisol testing provides fast, simple, reliable, and cost-effective screening for animals that have clinical signs compatible with hypoadrenocorticism. Sensitivity is high (99.4% to 100%) when resting cortisol is <2 µg/dL (<55 nmol/L)32-34; however, specificity is relatively low (63.3% to 78.2%), so it cannot be used as a confirmatory diagnostic test.32,34
Materials Needed: Serum separator tube
Interpretation: Basal/resting cortisol testing is better used as a test of exclusion for patients that have waxing and waning unexplained illness, have chronic gastrointestinal signs, or are highly suspected to have hypoadrenocorticism. That is, hypoadrenocorticism should be removed from the differential list for patients with resting cortisol levels of >2 µg/dL (>55 nmol/L). For patients with a resting cortisol of <2 µg/dL, an ACTH (adrenocorticotropic hormone) stimulation test should be performed to definitively diagnose hypoadrenocorticism.
Noninvasive Blood Pressure
Materials needed: Doppler unit and sphygmomanometer or oscillometric device, appropriately sized blood pressure cuff, ultrasonography gel (FIGURE 6).
Indications: Systemic arterial pressure is often referred to as the “fourth vital parameter” and provides valuable information about cardiovascular status for anesthetized patients, patients in emergent situations, and patients with associated diseases that pose a risk for the development of hypotension and hypertension. Arterial blood pressure plays a role not only in diagnosis but also in monitoring disease progression and guiding clinicians with therapeutic decision making.
Methods and interpretation: Indirect blood pressure measurement involves detecting arterial blood flow or vessel wall movement in a peripheral artery (palmar arterial arches of the forelimb or hindlimb or coccygeal artery of the tail). Oscillometric or Doppler sphygmomanometry techniques provide measurements of systolic arterial blood pressure.
Indirect blood pressure measurements can vary widely depending on the patient’s signalment and temperament, body condition, measurement technique, and operator experience. Several studies have identified a range of indirect systolic blood pressure measurements of 131 to 151 mm Hg for dogs and 115 to 162 mm Hg for cats (BOX 3).35
- Perform measurement in a quiet location away from other animals (clients should be present), allowing patients 5–10 minutes to acclimate before attempting blood pressure measurement.
- Position patients comfortably (i.e., ventral or lateral recumbency) and use minimal restraint (to reduce stress).
- Use a blood pressure cuff with a width that is 30%–40% of the limb circumference at the placement site (improperly sized cuffs result in falsely high or low readings).
- Always discard the first measurement.
- Record 5–7 consecutive measurements for each patient. If the blood pressure is trending downward, continue measuring until the decrease plateaus, after which record 5–7 consecutive measurements.
Continuous Glucose Monitoring
Cost of sensor: $$$ (FreeStyle Libre; Abbott, freestylelibre.us)
Materials: Flash glucose monitoring sensor with corresponding applicator and reading device
Methods and interpretation: Historically, glycemic control in patients has been monitored via in-hospital and at-home blood glucose curves, spot blood glucose measurements, urine glucose measurements, and fructosamine measurement.36 In recent years, flash glucose monitoring systems (FGMSs) have become more popular in veterinary medicine and provide an optimal, low-cost, low-stress way to monitor patients with diabetes. These factory-calibrated devices provide real-time estimates of blood glucose by constantly measuring the glucose concentration of the interstitial fluid through a disc-shaped sensor inserted into the subcutaneous space for up to 14 days. No blood sampling is required for patients with an FGMS; instead, the sensor has to be “flashed” with a portable reader or smartphone at least every 8 hours to retrieve, download, and store glucose measurements (FIGURE 7). The data can be uploaded to an online portal for remote interpretation by the clinician. Sensors are easily applied, are well tolerated, and have been validated in dogs and cats.37-41
Several studies in dogs and cats have indicated good correlation between blood glucose measurements by FGMSs and by point-of-care glucometers and automated biochemistry analyzers.38-44 Accuracy of FGMS measurements is lower for patients with diabetic ketoacidosis (DKA) and hypoglycemia (<70 mg/dL), most likely because of delayed equilibration of blood and interstitial glucose (i.e., rapid insulin-induced changes in blood glucose concentrations and dehydration) in DKA patients.41 Lag times between blood glucose and interstitial glucose have been reported as 5 to 10 minutes for dogs and 11.4 minutes for cats.38,39
Ideally, sensors should be placed in areas that are difficult for the patient to reach and where skin thickness is greater than 5 mm and has limited subcutaneous movement. The dorsal neck and lateral chest wall are commonly used sites.45,46 To lessen the chances of sensor displacement, the authors recommend placing 3 to 4 drops of cyanoacrylate tissue glue on the sensor surface adhesive after hair and skin site preparation but before sensor application. In cats, the authors prefer to place the sensor on the dorsal neck and to use Kitty Kollars (kittykollar.com) to further prevent the sensor from being dislodged.
After successful placement, the sensor is scanned to link the device to the reader; it takes 60 minutes before data can be collected from the sensor. Few complications are associated with FGMSs, the most common being premature detachment (up to 80%).36,42 Superficial contact dermatitis has been reported and usually resolves within several days after sensor removal. Sensor malfunction has been reported, potentially caused by:
- Inadequate placement of the sensor
- Excessive movement of the sensor leading to damage of the sensor filament
- Local bleeding impairing the acuity of the system
FGMS sensor performance may also be affected by x-ray radiation and magnetic resonance imaging. While sensor accuracy following imaging has not been studied, the authors recommend placement of sensors after imaging has been completed. Clients should be counseled that although current new-generation sensors are designed for up to 14-day use, most devices provide data for only 7 days before sensor failure. It is also imperative that clients be instructed to not adjust insulin dosages based on their interpretation of the curve created by the device. When unlikely values are reported, it is recommended to spot check a blood glucose to ensure accuracy.
In-house cytopathology is minimally invasive, rapid, and cost-effective. Its diagnostic value depends on the critical selection of appropriate lesions, good sampling technique, and quality sample handling.47 Its usefulness is substantial as incorporation of ultrasonography into veterinary practices has made sampling of internal organs/tissue more accessible, and most patients do not require sedation or anesthesia.
Cytopathology is used to confirm initial clinical impressions, often providing a definitive diagnosis. It is also used to guide clinicians with regard to initial client communications about the need for additional diagnostic workup (e.g., staging) and testing (e.g., molecular diagnostics, special stains, culture for infectious agents, immunocytochemistry, histopathology).
Materials: Needles (21 to 27 gauge), syringe (6 mL), glass microscope slides, Romanowsky-type stain, microscope with 4× to 100× objective lenses, immersion oil. Needle size does not significantly affect cytologic adequacy; however, poorly exfoliative sites require larger gauge needles.
Methods and interpretation: After sample collection, slides are initially evaluated for sample adequacy. Initial evaluation is performed under low power. Samples are then evaluated for diagnosis. Slides are scanned at low power, which is transitioned to a higher power to identify pathology.
The authors recommend categorizing slides as normal, inflammatory, or neoplastic. Definitive diagnosis is possible, but samples may need to be sent to an external laboratory or may require digital image–based telemedicine for pathology review.
Agreement between cytology and histopathology depends on sample recovery, lesion visualization, tissue sampling location, and method of collection. Agreement reportedly ranges from 33.3% to 66.1% (TABLE 4).48
Despite the ever-expanding assortment of diagnostic tests becoming available, do not overlook simple, practical, and affordable diagnostic tests. When performed correctly, these economical tests provide a wealth of information to facilitate diagnosis and treatment of patients.
- Bush BM. Interpretation of Laboratory Results for Small Animal Clinicians. 1st ed. Blackwell Science; 1992.
- Hematology (Advia 2120). Cornell University College of Veterinary Medicine. February 9, 2021. Accessed September 28, 2022. https://www.vet.cornell.edu/animal-health-diagnostic-center/laboratories/clinical-pathology/reference-intervals/hematology
- Reppas G, Foster SF. Practical urinalysis in the cat: 2: urine microscopic examination ‘tips and traps.’ J Feline Med Surg. 2016;18(5):373–385. doi:10.1177/1098612X16643249
- Reppas G, Foster SF. Practical urinalysis in the cat: 1: urine macroscopic examination ‘tips and traps.’ J Feline Med Surg. 2016;18(3):190–202. doi:10.1177/1098612X16631228
- Piech TL, Wycislo KL. Importance of urinalysis. Vet Clin North Am Small Anim Pract. 2019;49(2):233–245. doi:10.1016/j.cvsm.2018.10.005
- Rudinsky AJ, Wellman M, Tracy G, Stoltenberg L, DiBartola SP, Chew DJ. Variability among four refractometers for the measurement of urine specific gravity and comparison with urine osmolality in dogs. Vet Clin Pathol. 2019;48(4):702–709. doi:10.1111/vcp.12781
- Rudinsky A, Cortright C, Purcell S, et al. Variability of first morning urine specific gravity in 103 healthy dogs. J Vet Intern Med. 2019;33(5):2133–2137. doi:10.1111/jvim.15592
- Sink CA, Weinstein NM. Practical Veterinary Urinalysis. Wiley-Blackwell; 2012.
- Skeldon N, Ristić J. Urinalysis. In: Villiers E, Ristić J, eds. BSAVA Manual of Canine and Feline Clinical Pathology. 3rd ed. BSAVA; 2016:183-218.
- Johnson KY, Lulich JP, Osborne CA. Evaluation of the reproducibility and accuracy of pH-determining devices used to measure urine pH in dogs. JAVMA. 2007;230(3):364–369. doi:10.2460/javma.230.3.364
- Aldridge CF, Behrend EN, Smith JR, Welles EG, Lee HP. Accuracy of urine dipstick tests and urine glucose-to-creatinine ratios for assessment of glucosuria in dogs and cats. JAVMA. 2020;257(4):391-396. doi:10.2460/javma.257.4.391
- Willems A, Paepe D, Marynissen S, et al. Results of screening of apparently healthy senior and geriatric dogs. J Vet Intern Med. 2017;31(1):81-92. doi:10.1111/jvim.14587
- Rizzi TE. Urinalysis in companion animals, part 2: evaluation of urine chemistry & sediment. Todays Vet Pract. 2014;4(3):88-91.
- Behrend EN, Kooistra HS, Nelson R, Reusch CE, Scott-Moncrieff JC. Diagnosis of spontaneous canine hyperadrenocorticism: 2012 ACVIM consensus statement (small animal). J Vet Intern Med. 2013;27(6):1292–1304. doi:10.1111/jvim.12192
- Zeugswetter F, Bydzovsky N, Kampner D, Schwendenwein I. Tailored reference limits for urine corticoid:creatinine ratio in dogs to answer distinct clinical questions. Vet Rec. 2010;167(26):997-1001. doi:10.1136/vr.c4010
- Del Baldo F, Ferriani MG, Bertazzolo W, Luciani M, Tardo AM, Fracassi F. Urinary cortisol-creatinine ratio in dogs with hypoadrenocorticism. J Vet Intern Med. 2022;36(2):482-487. doi:10.1111/jvim.16358
- Rijnberk A, van Wees A, Mol J. Assessment of two tests for the diagnosis of canine hyperadrenocorticism. Vet Rec. 1988;122(8):178-180. doi:10.1136/vr.122.8.178
- Smiley LE, Peterson ME. Evaluation of a urine cortisol:creatinine ratio as a screening test for hyperadrenocorticism in dogs. J Vet Intern Med. 1993;7(3):163-168. doi:10.1111/j.1939-1676.1993.tb03181.x
- Moya MV, Refsal KR, Langlois DK. Investigation of the urine cortisol to creatinine ratio for the diagnosis of hypoadrenocorticism in dogs. JAVMA. 2022;260(9):1041-1047. doi:10.2460/javma.21.12.0538
- Randolph JF, Toomey J, Center SA, et al. Use of the urine cortisol-to-creatinine ratio for monitoring dogs with pituitary-dependent hyperadrenocorticism during induction treatment with mitotane (o,p’-DDD). Am J Vet Res. 1998;59(3):258–261.
- Galac S, Buijtels JJCWM, Kooistra HS. Urinary corticoid: creatinine ratios in dogs with pituitary-dependent hypercortisolism during trilostane treatment. J Vet Intern Med. 2009;23(6):1214-1219. doi:10.1111/j.1939-1676.2009.0374.x
- Angles JM, Feldman EC, Nelson RW, Feldman MS. Use of urine cortisol:creatinine ratio versus adrenocorticotropic hormone stimulation testing for monitoring mitotane treatment of pituitary-dependent hyperadrenocorticism in dogs. JAVMA. 1997;211(8):1002-1004.
- Feldman EC, Mack RE. Urine cortisol:creatinine ratio as a screening test for hyperadrenocorticism in dogs. JAVMA. 1992;200(11):1637-1641.
- Jensen AL, Iversen L, Koch J, Høier R, Petersen TK. Evaluation of the urinary cortisol: creatinine ratio in the diagnosis of hyperadrenocorticism in dogs. J Small Anim Pract. 1997;38(3):99-102. doi:10.1111/j.1748-5827.1997.tb03327.x
- Stolp R, Rijnberk A, Meijer JC, Croughs RJM. Urinary corticoids in the diagnosis of canine hyperadrenocorticism. Res Vet Sci. 1983;34(2)141-144.
- Galeandro L, Sieber-Ruckstuhl NS, Riond B, et al. Urinary corticoid concentrations measured by 5 different immunoassays and gas chromatography-mass spectrometry in healthy dogs and dogs with hypercortisolism at home and in the hospital. J Vet Intern Med. 2014;28(5):1433-1441. doi:10.1111/jvim.12399
- Kaplan AJ, Peterson ME, Kemppainen RJ. Effects of disease on the results of diagnostic tests for use in detecting hyperadrenocorticism in dogs. JAVMA. 1995;207(4):445-451.
- Vonderen IK, Kooistra HS, Rijnberk A. Influence of veterinary care on the urinary corticoid:creatinine ratio in dogs. J Vet Intern Med. 1998;12(6):431-435. doi:10.1111/j.1939-1676.1998.tb02146.x
- Citron LE, Weinstein NM, Littman MP, Foster JD. Urine cortisol-creatinine and protein-creatinine ratios in urine samples from healthy dogs collected at home and in hospital. J Vet Intern Med. 2020;34(2):777-782. doi:10.1111/jvim.15735
- Lees GE, Brown SA, Elliott J, Grauer GF, Vaden SL. Assessment and management of proteinuria in dogs and cats: 2004 ACVIM forum consensus statement (small animal). J Vet Intern Med. 2005;19(3):377-385. doi:10.1111/j.1939-1676.2005.tb02713.x
- Shropshire S, Quimby J, Cerda R. Comparison of single, averaged, and pooled urine protein:creatinine ratios in proteinuric dogs undergoing medical treatment. J Vet Intern Med. 2017;32(1):288-294. doi:10.1111/jvim.14872
- Bovens C, Tennant K, Reeve J, Murphy KF. Basal serum cortisol concentration as a screening test for hypoadrenocorticism in dogs. J Vet Intern Med. 2014;28(5):1541-1545. doi:10.1111/jvim.12415
- Gold AJ, Langlois DK, Refsal KR. Evaluation of basal serum or plasma cortisol concentrations for the diagnosis of hypoadrenocorticism in dogs. J Vet Intern Med. 2016;30(6):1798-1805. doi:10.1111/jvim.14589
- Lennon EM, Boyle TE, Hutchins RG, et al. Use of basal serum or plasma cortisol concentrations to rule out a diagnosis of hypoadrenocorticism in dogs: 123 cases (2000–2005). JAVMA. 2007;231(3):413-416. doi:10.2460/javma.231.3.413
- Acierno MJ, Brown S, Coleman AE, et al. Guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats. J Vet Intern Med. 2018;32(6):1803-1822. doi:10.1111/jvim.15331
- Shoelson AM, Mahony OM, Pavlick M. Complications associated with a flash glucose monitoring system in diabetic cats. J Feline Med Surg. 2020;23(6):557-562. doi:10.1177/1098612X20965012
- Corradini S, Pilosio B, Dondi F, et al. Accuracy of a flash glucose monitoring system in diabetic dogs. J Vet Intern Med. 2016;30(4):983-988. doi:10.1111/jvim.14355
- Malerba E, Cattani C, Del Baldo F, et al. Accuracy of a flash glucose monitoring system in dogs with diabetic ketoacidosis. J Vet Intern Med. 2020;34(1):83-91. doi:10.1111/jvim.15657
- Silva DD, Cecci G, Biz G, Chiaro FN, Zanutto MS. Evaluation of a flash glucose monitoring system in dogs with diabetic ketoacidosis. Domest Anim Endocrinol. 2021;74:106525. doi:10.1016/j.domaniend.2020.106525
- Shea EK, Hess RS. Assessment of postprandial hyperglycemia and circadian fluctuation of glucose concentrations in diabetic dogs using a flash glucose monitoring system. J Vet Intern Med. 2021;35(2):843-852. doi:10.1111/jvim.16046
- Del Baldo F, Canton C, Testa S, et al. Comparison between a flash glucose monitoring system and a portable blood glucose meter for monitoring dogs with diabetes mellitus. J Vet Intern Med. 2020;34(6):2296-2305. doi:10.1111/jvim
- Shea EK, Hess RS. Validation of a flash glucose monitoring system in outpatient diabetic cats. J Vet Intern Med. 2021;35(4):1703-1712. doi:10.1111/jvim.16216
- Del Baldo F, Fracassi F, Pires J, et al. Accuracy of a flash glucose monitoring system in cats and determination of the time lag between blood glucose and interstitial glucose concentrations. J Vet Intern Med. 2021;35(3):1279-1287. doi:10.1111/jvim.16122
- Deiting V, Mischke R. Use of the “FreeStyle Libre” glucose monitoring system in diabetic cats. Res Vet Sci. 2021;135:253-259. doi:10.1016/j.rvsc.2020.09.015
- Koenig A, Hoenig ME, Jimenez DA. Effect of sensor location in dogs on performance of an interstitial glucose monitor. Am J Vet Res. 2016;77(8):805-817. doi:10.2460/ajvr.77.8.805
- Del Baldo F, Diana A, Canton C, Linta N, Chiocchetti R, Fracassi F. The influence of skin thickness on flash glucose monitoring system accuracy in dogs with diabetes mellitus. Animals. 2021;11(2):408. doi:10.3390/ani11020408
- Sharkey LC, Dial SM, Matz ME. Maximizing the diagnostic value of cytology in small animal practice. Vet Clin North Am Small Anim Pract. 2007;37(2):351-372. doi:10.1016/j.cvsm.2006.11.004
- Cohen M, Bohling MW, Wright JC, Welles EA, Spano JS. Evaluation of sensitivity and specificity of cytologic examination: 269 cases (1999–2000). JAVMA. 2003;222(7):964–967. doi:10.2460/javma.2003.222.964
- Simon D, Schoenrock D, Nolte I, Baumgärtner W, Barron R, Mischke R. Cytologic examination of fine-needle aspirates from mammary gland tumors in the dog: diagnostic accuracy with comparison to histopathology and association with postoperative outcome. Vet Clin Pathol. 2009;38(4):521-528. doi:10.1111/j.1939-165X.2009.00150.x
- Ballegeer EA, Forrest LJ, Dickinson RM, Schutten MM, Delaney FA, Young KM. Correlation of ultrasonographic appearance of lesions and cytologic and histologic diagnoses in splenic aspirates from dogs and cats: 32 cases (2002–2005). JAVMA. 2007;230(5):690-696. doi:10.2460/javma.230.5.690
- Christensen NI, Canfield PJ, Martin PA, Krockenberger MB, Spielman DS, Bosward KL. Cytopathological and histopathological diagnosis of canine splenic disorders. Aust Vet J. 2009;87(5):175-181. doi:10.1111/j.1751-0813.2009.00421.x
- Sharkey LC, Seelig DM, Overmann J. All lesions great and small, part 1: diagnostic cytology in veterinary medicine. Diagn Cytopathol. 2014;42(6):535-543. doi:10.1002/dc.23097
- Caniatti M, Cunha NP, Avallone G, et al. Diagnostic accuracy of brush cytology in canine chronic intranasal disease. Vet Clin Pathol. 2012;41(1):133-140. doi:10.1111/j.1939-165X.2011.00388.x