Automated flow cytometric cell count and differentiation of canine cerebrospinal fluid cells using the ADVIA 2120

Background: Microscopic cell counts in cerebrospinal fluid (CSF) are time-consuming and prone to imprecision. The recently introduced automated hematology analyzer ADVIA 2120 offers an automated cell count and differential for CSF in the veterinary software mode based on laser light scatter and absorbance measurements. Objectives: The purpose of this study was to evaluate the precision, linearity, and accuracy of the ADVIA 2120 CSF assay. Methods: Sixty-seven CSF samples were analyzed on the ADVIA 2120 and total nucleated cell counts (TNCC) and RBC counts were compared with the hemocytometer results. In 21 samples with TNCC >5/muL, ADVIA 2120 results were compared with 100-300 cell manual differentials performed on cytocentrifuged preparations. Statistical analysis included Spearman's rank correlation, Passing-Bablok regression, and Bland-Altman analysis. Results: Repeatability (intra-assay) coefficients of variation (CVs) ranged from 4.19% to 25.94%. Interassay CVs ranged from 2.56% to 28.67%. Accurate results within 30% were achieved for TNCC up to 4000/muL. Except for low TNCC, deviation from the expected value was higher (TNCC of 8/muL instead of 4/muL). The following correlation coefficients (r) and biases were achieved compared with the reference method: r=.90 and bias 2.3/muL for TNCC; r=.88 and bias 32.0/muL for RBC counts; r=.86 and bias +/-13.4% for mononuclear and polymorphonuclear cell percentages; r=.88 and bias -6.1% for lymphocyte percentage; r=.56 and bias 19.4% for monocyte percentage; and r=.75 and bias -9.7% for neutrophil percentage. Conclusion: Our results demonstrated that the automated ADVIA 2120 CSF assay generally compares well with reference methods although there are some limitations for the automated monocyte count and for samples with only mild pleocytosis.     

Evaluation of equine hemograms using the ADVIA 120 as compared with an impedance counter and manual differential count

BACKGROUND: The ADVIA 120 is an automated laser cell counter widely used in veterinary medicine. Although specific software for equine samples is available and validated, only a few reports have been published comparing the ADVIA 120 with other methods for equine hemogram evaluation. OBJECTIVES: The purpose of this study was to compare the hematologic values and reference intervals obtained on the ADVIA 120 with those obtained on an impedance cell counter and manual differential counts in healthy horses. METHODS: EDTA-anticoagulated blood samples were obtained from 114 clinically healthy horses of various breeds, both sexes, and 2-6 years of age. Samples were stored for up to 12 hours at 4 degrees C and then analyzed on the ADVIA 120 and the Hemat 8. A 100-cell to 200-cell differential leukocyte count was performed by 3 independent observers on May-Grünwald-Giemsa-stained smears. Intra-assay precision of the ADVIA 120 was determined by analyzing 5 replicates each of 10 of the blood samples. RESULTS: Results from the ADVIA were significantly higher than those from the impedance counter for RBC count, total WBC count, hemoglobin concentration, red cell distribution width, MCH, and MCHC, and significantly lower for HCT and platelet count. Significantly higher neutrophil and basophil counts and significantly lower lymphocyte counts were obtained with the ADVIA 120 compared with manual counts. Based on Passing-Bablok regression analysis, RBC and platelet counts were in good agreement between the 2 analyzers; a constant and proportional bias was present for other values. Coefficients of variation for erythrocyte parameters on the ADVIA were <1%, but were higher for platelet (6%), total WBC (2%), differential WBC (4%-30%), and reticulocyte (75%) counts. CONCLUSIONS: Results obtained with equine samples on the ADVIA 120 were comparable with those obtained on an impedance counter; reference intervals differed statistically but overlapped. The ADVIA had poor precision for reticulocyte and differential leukocyte counts such that the latter should always be verified on smears.     

Comparative clinical study of canine and feline total blood cell count results with seven in‐clinic and two commercial laboratory hematology analyzers

Background: A CBC is an integral part of the assessment of health and disease in companion animals. While in the past newer technologies for CBC analysis were limited to large clinical pathology laboratories, several smaller and affordable automated hematology analyzers have been developed for in‐clinic use. Objectives: The purpose of this study was to compare CBC results generated by 7 in‐clinic laser‐ and impedance‐based hematology instruments and 2 commercial laboratory analyzers. Methods: Over a 3‐month period, fresh EDTA‐anticoagulated blood samples from healthy and diseased dogs (n=260) and cats (n=110) were analyzed on the LaserCyte, ForCyte, MS45, Heska CBC, Scil Vet ABC, VetScan HMT, QBC Vet Autoread, CELL‐DYN 3500, and ADVIA 120 analyzers. Results were compared by regression correlation (linear, Deming, Passing‐Bablok) and Bland–Altman bias plots using the ADVIA as the criterion standard for all analytes except HCT, which was compared with manual PCV. Precision, linearity, and carryover also were evaluated. Results: For most analytes, the in‐clinic analyzers and the CELL‐DYN performed similarly and correlated well with the ADVIA. The biases ranged from ?0.6 to 2.4 × 10⁹/L for WBC count, 0 to 0.9 × 10¹²/L for RBC count, ?1.5 to 0.7 g/dL for hemoglobin concentration, ?4.3 to 8.3 fL for MCV, and ?69.3 to 77.2 × 10⁹/L for platelet count. Compared with PCV, the HCT on most analyzers had a bias from 0.1% to 7.2%. Canine reticulocyte counts on the LaserCyte and ForCyte correlated but had a negative bias compared with those on the ADVIA. Precision, linearity, and carryover results were excellent for most analyzers. Conclusions: Total WBC and RBC counts were acceptable on all in‐clinic hematology instruments studied, with limitations for some RBC parameters and platelet counts. Together with evaluation of a blood film, these in‐clinic instruments can provide useful information on canine and feline patients in veterinary practices.     

Analysis of canine and feline haemograms using the VetScan HMT analyser

The VetScan HMT is an impedance counter haematology analyser which produces a full blood count and three-part white blood cell differential. The aim of this study was to compare the results generated by the analyser with those obtained by standard methods used routinely in the authors' laboratory. Blood samples from 68 dogs and 59 cats were run on the VetScan HMT analyser and also subjected to reference methods, and the results obtained were compared. Correlation coefficients (feline/canine) were: 0.97/0.99 for haematocrit (Hct), 0.98/0.99 for haemoglobin (Hb), 0.81/0.98 for total white blood cells (WBC), and 0.89/0.97 for granulocyte and 0.65/0.93 for platelet counts. Coefficients for lymphocyte counts were 0.25/0.28 and for monocyte counts were 0.12/0.79. In conclusion, the VetScan HMT performed well on canine samples, showing excellent correlation for canine Hct, Hb, RBC, WBC, granulocyte and platelet counts. For feline samples, although there was excellent correlation for Hct, Hb and RBC, the WBC and three-part white blood cell differential and platelet count should be interpreted with caution as they can be unreliable.     

Comparison between microscopic and automated differential leukocyte counts in the silver fox (Vulpes vulpes) and the blue fox (Alopex lagopus)

Differential leukocyte (WBC) counts in blood from clinically healthy silver foxes (n=32) and blue foxes (n=37) obtained from an automated hematology analyzer (Technicon H*1 Hematology System) with canine software were compared with microscopic differential WBC counts (M-diff). There was good agreement between the automated differential cell count (A-diff) and the M-diff for neutrophil and lymphocyte percentages. The correlation was lower for monocyte percentages and variable for eosinophil percentages. There was no significant difference between the A-diff and M-diff in either fox species. The A-diff counts were very precise, and may be a good alternative to the traditional M-diff for screening populations of clinically healthy foxes or for studies on stress and animal welfare. Intercept values, however, indicated a constant bias that must be taken into account before interpreting results based on different methods of analysis     

Evaluation of an in-house centrifugal hematology analyzer for use in veterinary practice

OBJECTIVE: To compare CBC results obtained by use of an in-house centrifugal analyzer with results of a reference method. DESIGN: Prospective study. SAMPLE POPULATION: Blood samples from 147 dogs, 42 cats, and 60 horses admitted to a veterinary teaching hospital and from 24 cows in a commercial dairy herd. PROCEDURE: Results obtained with the centrifugal analyzer were compared with results obtained with an electrical-impedance light-scatter hematology analyzer and manual differential cell counting (reference method). RESULTS: The centrifugal analyzer yielded error messages for 50 of 273 (18%) samples. Error messages were most common for samples with values outside established reference ranges. Correlation coefficients ranged from 0.80 to 0.99 for Hct, 0.55 to 0.90 for platelet count, 0.76 to 0.95 for total WBC count, and 0.63 (cattle) to 0.82 (cats) to 0.95 (dogs and horses) for granulocyte count. Coefficients for mononuclear cell (combined lymphocyte and monocyte) counts were 0.56, 0.65, 0.68, and 0.92 for cats, horses, dogs, and cattle, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that there was an excellent correlation between results of the centrifugal analyzer and results of the reference method only for Hct in feline, canine, and equine samples; WBC count in canine and equine samples; granulocyte count in canine and equine samples; and reticulocyte count in canine samples. However, an inability to identify abnormal cells, the high percentage of error messages, particularly for samples with abnormal WBC counts, and the wide confidence intervals precluded reliance on differential cell counts obtained with the centrifugal analyzer.     

Association of cerebrospinal fluid analysis findings with clinical signs and outcome in acute nonambulatory thoracolumbar disc disease in dogs

Background: Cerebrospinal fluid (CSF) pleocytosis recently was associated with the severity of neurologic signs in dogs with intervertebral disc disease (IVDD). Hypothesis/Objectives: To look for an association among CSF cell counts, total protein concentration, and severity of neurologic signs at presentation with outcome in dogs with acute thoracolumbar IVDD. Our hypothesis was that CSF total nucleated cell count (TNCC) and percentage cell types would be associated with the severity of spinal cord damage and therefore with both the presenting clinical signs and the prognosis of affected dogs. Animals: Fifty‐four dogs with acute nonambulatory thoracolumbar IVDD were evaluated. Methods: Retrospective study. Signalment, neurologic grade, CSF TNCC, protein concentration, red blood cells count and differential cell percentages, and short‐ and long‐term outcomes were evaluated. Results: CSF pleocytosis (>5 cells/μL) was present in 54% of dogs and was positively associated with neurologic grade at presentation and with postoperative time to regaining ambulation. Neutrophils were observed most frequently. The percentage of CSF macrophages and macrophage to monocyte ratio were higher (P= .001, for both) in dogs presented without deep pain sensation (DPS) that did not regain ambulation. Receiver operator characteristics curve analysis yielded a cut‐off point of 13% macrophages with a sensitivity and specificity of 100 and 83%, respectively, for prediction of a negative outcome. Conclusions and Clinical Importance: CSF pleocytosis is positively associated with the severity of spinal cord damage in dogs with thoracolumbar IVDD. The percentage of CSF macrophages can be used as a prognostic indicator for regaining ambulation in dogs that have lost DPS.     

Reference intervals for feline cerebrospinal fluid: cell counts and cytologic features

Reference intervals for feline CSF cell counts and cytologic variables were determined. Values were derived from 58 adult cats that had normal neurologic examination findings and did not have histologic lesions of the CNS. Effect of age or gender was not apparent for any CSF variable, and no CSF variable was significantly correlated with its corresponding blood value. Total WBC count and neutrophil and eosinophil percentages were positively correlated with the CSF RBC count. Thus, proposed reference intervals for feline CSF were derived from 33 cats with CSF RBC count of less than 31 cells/ul. Data for CSF samples with range between 31 and 1,700 RBC/microliters were also determined. Erythrocyte count was not significantly different in CSF collected, using 20- or 22-gauge spinal needles.     

Reassessment of cytologic values in canine cerebrospinal fluid by use of cytocentrifugation

Using cytocentrifugation, nearly one fourth of canine cerebrospinal fluid (CSF) samples with cell counts in the normal range had abnormalities in cell type or morphologic features. Cerebrospinal fluid samples from 145 dogs with neurologic disorders were evaluated by use of this method. These results indicate that low hemacytometer counts in canine CSF should not be interpreted as normal. By increasing the detection of abnormalities in CSF, cytocentrifugation might improve diagnosis and treatment of canine neurologic disease.     

Rapid,effective and user-friendly immunophenotyping of canine lymphoma using a personal flow cytometer

Background

Widespread use of flow cytometry for immunophenotyping in clinical veterinary medicine is limited by cost and requirement for considerable laboratory space, staff time, and expertise. The Guava EasyCyte Plus (Guava Technologies, Hayward, CA, US) is the first, personal, bench-top flow cytometer designed to address these limitations.

Objective

The aim of this study was to adapt the immunohistochemical protocol used for immunophenotyping of canine lymphoma to the personal flow cytometer for rapid, effective and user-friendly application to the diagnosis and prognosis of canine lymphoma and to demonstrate its practicality for widespread veterinary application. Performance of the personal flow cytometer for immunophenotyping T and B lymphocytes in blood and lymph nodes from normal dogs and dogs with lymphoproliferative disease, was assessed using only two monoclonal antibodies (against CD3 and CD21), and by comparison with analysis using two conventional flow cytometers.

Methods

26 dogs with lymphoproliferative disease (23 with lymphoma, 3 with lymphocytic leukaemia) were studied along with 15 controls (2 non-lymphoma lymph nodes and 13 non-leukemic bloods. Lymphocytes were immunostained with fluorescent-labeled, monoclonal antibodies against CD3 and CD21. To assess the effectiveness of the personal flow cytometer in discrimination between T and B cell immunophenotypes, T and B cell counts for half the samples (14 blood and 11 lymph node) were also determined using the same method and conventional flow cytometers (FACSCalibur, Cyan Dako). To assess the effectiveness of the personal flow cytometer in discriminating between leukocyte types, lymphocyte differential counts were determined for 21 blood samples and compared with those from automated hematology analyzers (CELL-DYN 3500, n=11 and ADVIA 2120, n=10). Quality and sub-cellular distribution of immunostaining was assessed using fluorescence microscopy.

Results

The protocol for immunophenotyping took 2 to 3 hours to complete from the point of receipt of sample to reporting of immunophenotype. The personal flow cytometer differential lymphocyte counts correlated highly (n=20; r=0.97, p<0.0001) with those of automated haematology analyzers. The personal flow cytometer counts consistently, but mildly, underestimated the percentages of lymphocytes in the samples (mean bias of -5.3%.). The personal flow cytometer immunophenotype counts were indistinguishable from those of conventional flow cytometers for both peripheral blood samples (n=13; r=0.95; p<0.0001; bias of -1.1%) and lymph node aspirates (n=11,r=0.98; p<0.001; bias of 1%). All but one leukemic and one lymphomatous lymph node sample, out of 26 samples of dogs with lymphoproliferative disease analyzed, could be immunophenotyped as either B or T cells.

Conclusions

We conclude that use of only 2 monoclonal antibodies is sufficient for immunophenotyping most cases of canine lymphoma by flow cytometry and enables rapid immunophenotyping. The personal flow cytometer may be as effectively used for immunophenotyping canine lymphoma as conventional flow cytometers. However, the personal flow cytometer is more accessible and user-friendly, and requires lower sample volumes.     

Clinical evaluation of the CA530-VET hematology analyzer for use in veterinary practice

BACKGROUND: The CA530-VET is a completely automated impedance cell hematology analyzer, which yields a 16-parameter blood count including a 3-part leukocyte differential. OBJECTIVES: The aim of this study was to examine the operational potential of the CA530-VET and its value for use in veterinary practice. METHODS: The analyzer was tested for blood carry-over, precision, and accuracy. Comparison methods included the CELL-DYN 3500, microhematocrit centrifugation, manual platelet (PLT) counting for feline and equine species, and a 100-cell manual WBC differential. Blood samples for comparison of the methods were obtained from 242 dogs, 166 cats, and 144 horses. RESULTS: The carry-over ratio (K) was 0.28% for RBC, 0.59% for PLT, 0.32% for WBC, and 0.18% for hemoglobin (HGB) concentration. Coefficients of variation (CVs) for within-batch precision and duplicate measurement of blood samples were clearly within the required limits, except for duplicate platelet counts in cats (8.7%) and horses (9.5%). The WBC count was in excellent agreement for dogs and horses and RBC count was in excellent agreement for horses. The accuracy of feline WBC counts was not acceptable, with the exception of values at the high end of the range. RBC counts in dogs and cats, and HGB concentration and MCV in all 3 species were sufficiently accurate. The CA530-VET HCT results were in excellent agreement with microhematocrit results in horses but exceeded the maximum allowed inaccuracy for cats and dogs. In all species, PLT counts established mechanically and manually were not in adequate agreement. Large differences were found between the CA530-VET and the manual differential percentage for lymphocytes and "mid-sized cells" (monocytes and basophilic granulocytes). CONCLUSIONS: The CA530-VET can be considered useful for routine canine, feline, and equine blood cell analyses. It should not be considered accurate, however, for PLT counts, feline total WBC counts in the subnormal and normal range, and leukocyte differentials, except for granulocytes.     

Artifactual changes in canine blood following storage, detected using the ADVIA 120 hematology analyzer

BACKGROUND: Artifactual changes in blood may occur as a consequence of delayed analysis and may complicate interpretation of CBC data. OBJECTIVE: The aim of this study was to characterize artifactual changes in canine blood, due to storage, using the ADVIA 120 hematology analyzer. METHODS: Blood samples were collected into EDTA from 5 clinically healthy dogs. Within 1 hour after blood sample collection and at 12, 24, 36 and 48 hours after storage of the samples at either 4 degrees C or room temperature (approximately 24 degrees C), a CBC was done using the ADVIA 120 and multispecies software. A linear mixed model was used to statistically evaluate significant differences in values over time, compared with initial values. RESULTS: The HCT and MCV were increased significantly after 12 hours of collection at both 4 degrees C and 24 degrees C, and continued to increase through 48 hours. The MCHC initially decreased significantly at 12-24 hours and then continued to decrease through 48 hours at both temperatures. Changes in HCT, MCV, and MCHC were greater at 24 degrees C than at 4 degrees C at all time points. A significant increase in MPV and a decrease in mean platelet component concentration were observed at all time points at 24 degrees C. Samples stored at 24 degrees C for 48 hours had significantly higher percentages of normocytic-hypochromic RBCs, and macrocytic-normochromic RBCs, and lower platelet and total WBC counts. CONCLUSIONS: Delayed analysis of canine blood samples produces artifactual changes in CBC results, mainly in RBC morphology and platelet parameters, that are readily detected using the ADVIA 120. Refrigeration of specimens, even after 24 hours of storage at room temperature, is recommended to improve the accuracy of CBC results for canine blood samples.     

Evaluation of a point-of-care hematology analyzer for use in dogs and cats receiving chemotherapeutic treatment

OBJECTIVE: To compare WBC, neutrophil, and platelet counts and Hct values obtained with a point-of-care hematology analyzer with values obtained by a reference method for dogs and cats receiving chemotherapy. DESIGN: Cross-sectional study. ANIMALS:105 dogs and 25 cats undergoing chemotherapy. PROCEDURES:Blood samples were analyzed with a point-of-care hematology analyzer and with an impedance- and laser-based analyzer with manual differential WBC counts. Results for WBC, neutrophil, and platelet counts and Hct were compared. Sensitivity and specificity of the point-of-care analyzer to detect leukopenia, neutropenia, and anemia were calculated. RESULTS: 554 canine and 96 feline blood samples were evaluated. Correlation coefficients for dogs and cats, respectively, were 0.92 and 0.95 for total WBC count, 0.91 and 0.88 for neutrophil count, 0.95 and 0.92 for Hct, and 0.93 and 0.71 for platelet count. Sensitivity and specificity, respectively, of the point-of-care analyzer to detect leukopenia were 100% and 75% for dogs and 100% and 68% for cats; to detect neutropenia were 80% and 97% for dogs and 100% and 80% for cats; to detect anemia were 100% and 80% for dogs and 100% and 66% for cats; and to detect thrombocytopenia were 86% and 95% for dogs and 50% and 87% for cats. CONCLUSIONS AND CLINICAL RELEVANCE:The point-of-care analyzer was reliable for monitoring CBCs of dogs and cats receiving chemotherapy. It had good to excellent correlation for WBC and neutrophil counts and Hct and accurately detected leukopenia, neutropenia, and anemia. Sensitivity of the analyzer for detecting thrombocytopenia was lower but acceptable.     

Characteristics of cisternal cerebrospinal fluid associated with intracranial meningiomas in dogs: 56 cases (1985-2004)

OBJECTIVE: To determine CSF characteristics associated with intracranial meningiomas in dogs. DESIGN: Retrospective case series. ANIMALS: 56 dogs with intracranial meningiomas. PROCEDURES: Medical records of dogs with a histopathologic diagnosis of intracranial meningioma, in which CSF analysis had been performed, were reviewed. Information concerning total nucleated cell counts (TNCCs) and differential nucleated cell counts, RBC counts, and total protein concentration in CSF; seizure history and glucocorticoid administration; and location of meningiomas was recorded. RESULTS: TNCCs < 5 cells/microL were detected in 41 of 56 (73%) dogs; 5 of 56 (9%) dogs had TNCCs > 50 cells/microL. Analysis of CSF revealed predominantly neutrophilic pleocytosis in < 20% of dogs. There was a significant association between meningioma location (caudal portion of the cranial fossa or middle and rostral portion of the cranial fossae) and increased TNCCs (> or = 5 cells/microL). CONCLUSIONS AND CLINICAL RELEVANCE: Results were significantly different from those routinely reported in the veterinary literature. Neutrophilic pleocytosis, especially with TNCCs > 50 cells/microL, was not typical in CSF samples from dogs with intracranial meningiomas. Neutrophilic pleocytosis may not be detected in CSF samples from dogs with meningiomas located within the middle or rostral portion of the cranial fossae.     

Analysis of feline,canine and equine hemograms using the QBC VetAutoread

Blood samples form 120 consecutive clinical cases (40 cats, 40 dogs and 40 horses) were analyzed on the QBC VetAutoread analyzer and the results compared with those obtained by a Baker 9000 electronic resistance cell counter and a 100-cell manual differential leukocyte (WBC) count. Packed cell volume (PCV), hemoglobin (Hb) concentration, mean cell hemoglobin concentration (MCHC), and platelet, total WBC, granulocytes, and lymphocyte plus monocyte (L+M) counts were determined. Indistinct separation of red blood cell and granulocytes layers on the QBC VetAutoread was observed in samples from five cats (12.5%), two dogs (5%), and one horse. Significantly different (P=0.002) median values for the two methods were obtained for PCV, Hb concentration, MCHC and platelet count in cats; PCV, MCHC, WBC, count and granulocytes count in dogs; and PCV, Hb concentration, MCHC and WBC, granulocytes and platelet counts in horses. Results from the QBC VetAutoread should not be interpreted using reference ranges established using other equipment. Results were abnormal on a limited number of samples; however, when correlation coefficients were low, marked discrepancy existed between values within as well as outside of reference ranges. Spearman rank correlation coefficients were excellent (r=0.93) for PCV and Hb concentration in dogs, and Hb concentration and WBC count in horses. Correlation was good (r=0.80-0.92) for PCV and Hb concentration in cats, WBC count in dogs, and PCV, granulocytes count and platelet count in horses. For remaining parameters, correlation was fair to poor (r=0.79). Acceptable correlations (r>0.80) were achieved between the two test systems for all equine values except MCHC and L+M count, but only for PCV and HB concentration in feline and canine blood samples.     

Canine complete blood counts: a comparison of four in‐office instruments with the ADVIA 120 and manual differential counts

Background: With more use of bench‐top in‐office hematology analyzers, the accuracy of reported values is increasingly important. Instruments use varied methods for cell counting and differentiation, and blood smears may not always be examined. Objective: The purpose of this study was to compare canine CBC results using 4 bench‐top instruments (Hemavet 950, Heska CBC‐Diff, IDEXX LaserCyte, and IDEXX VetAutoread) with ADVIA 120 and manual leukocyte counts. Methods: EDTA‐anticoagulated canine blood samples (n=100) were analyzed on each instrument. Manual differentials were based on 100‐cell counts. Linear regression, difference plots, paired t‐tests, and estimation of diagnostic equivalence were used to analyze results. Results: Correlations of HCT, WBC, and platelet counts were very good to excellent between all in‐office instruments and the ADVIA 120, but results varied in accuracy (comparability). Hemavet 950 and Heska CBC‐Diff results compared best with ADVIA results and manual leukocyte differentials. HCT and platelet counts on the IDEXX VetAutoread compared well with those from the ADVIA. Except for neutrophil counts, leukocyte differentials from all instruments compared poorly with ADVIA and manual counts. Reticulocyte counts on the LaserCyte and VetAutoread compared poorly with those from the ADVIA. Conclusions: The Hemavet 950 and Heska CBC‐Diff performed best of the 4 analyzers we compared. HCT, WBC, and platelet counts on the LaserCyte had minimally sufficient comparability for diagnostic use. Except for neutrophils (granulocytes), leukocyte differential counts were unreliable on all in‐office analyzers. Instruments with a 5‐part leukocyte differential provided no added benefit over a 3‐part differential. Assessment of erythrocyte regeneration on the LaserCyte and VetAutoread was unreliable compared with the ADVIA 120.     

Estimating leukocyte,platelet, and erythrocyte counts in rats by blood smear examination

Background: The CBC is an essential test for assessing the health of rats used in drug development studies. Because of limited blood volume, estimates of cell counts from a blood smear would be valuable when other analytical methods of enumerating cells are not possible or available. Objective: The purpose of this study was to develop a statistical model to accurately estimate WBC, platelet (PLT), and RBC counts in blood smears from rats. Method: Blood smears and quantitative cell counts were obtained from vehicle‐treated male and female Fischer 344 rats (n=65) involved in a variety of studies. The numbers of WBCs, PLTs, and RBCs were estimated in 10 fields in the monolayer of smears using × 20 (WBC) or × 100 (PLT, RBC) objectives. Using a statistical model and the quantitative cell counts obtained on an ADVIA 120 hematology analyzer, formulas were developed to predict the quantitative counts from the estimates. Results: Data were log‐transformed before analysis. A formula was derived using the slope and intercept of the regression line between cell estimates and ADVIA counts to predict WBC, PLT, and RBC counts based only on estimates. A second formula was developed for situations in which limited quantitative analyses may be available, and resulted in even more accurately predicted counts from smear estimates. Conclusion: The formulas developed in this study can be a valuable tool in estimating cell counts from a blood smear when cell counting instruments are not available or when an instrument cell count needs to be verified. These formulas may be useful in the assessment of rat blood in discovery and lead optimization studies.     

Cytologic interpretation of canine cerebrospinal fluid samples with low total nucleated cell concentration,with and without blood contamination

Background: Cerebrospinal fluid (CSF) is potentially altered by iatrogenic blood contamination at the time of sampling due to the addition of blood‐associated leukocytes and protein. Objectives: The objective of this study was to assess whether protein concentration, neutrophil percentage, and the presence of activated macrophages, reactive lymphocytes, or eosinophils in CSF samples with low total nucleated cell concentration (TNCC) are affected by blood contamination or associated with central nervous system (CNS) disease. Methods: Case records from the Royal Veterinary College Diagnostic Laboratory were searched retrospectively for dogs with CSF having ≤5 TNCC/μL. TNCC, RBC, and protein concentrations; neutrophil percentage; and the presence of activated macrophages, reactive lymphocytes, and eosinophils were recorded. Results of magnetic resonance imaging (MRI) also were recorded as a marker of CNS disease. Results: Of 906 cases evaluated, 106 (12%) had blood contamination (>500 RBCs/μL) in CSF. Protein concentration and neutrophil percentage were significantly higher and the presence of eosinophils was more likely in blood contaminated vs noncontaminated samples. Non‐blood‐contaminated samples with activated macrophages or reactive lymphocytes had higher protein concentrations and neutrophil percentages, and those with activated macrophages were more likely to have a positive finding on MRI. Conclusions: Protein concentration, neutrophil percentage, and the presence of eosinophils are significantly affected by blood contamination in canine CSF having low TNCC. Activated macrophages and reactive lymphocytes are not affected by blood contamination, however, and may be useful in identifying dogs with CNS abnormalities.     

Interpretation of canine and feline blood smears by emergency room personnel

Background: Interpretation of blood smears is commonly used to provide rapid laboratory evaluation of animals in veterinary emergency practice, but the accuracy of results of blood smear interpretation by emergency room personnel (ERP) compared with evaluation by trained veterinary clinical pathology personnel is unknown. Objective: The goal of this study was to compare blood smear evaluation by ERP with that of clinical pathology personnel. Methods: All animals that had a CBC determined by a diagnostic laboratory and had blood smears evaluated by personnel at the Foster Hospital for Small Animals Emergency Room between September 2008 and July 2009 were eligible for study inclusion. ERP who evaluated blood smears completed standardized forms with estimates of the WBC and platelet counts and evaluation of RBC and WBC morphology. Results from point‐of‐care assessment were compared with automated or manual results reported by the veterinary diagnostic laboratory. Results: One hundred and fifty‐five blood smears were evaluated. There was moderate agreement (κ value, 0.63; 95% confidence interval [CI]: 0.52, 0.74) between estimated platelet counts by ERP and automated counts. Poor agreement was found between estimated WBC counts by ERP and automated counts (κ value, 0.48; 95% CI: 0.37, 0.60). Specific abnormalities with a high likelihood of clinical significance, eg, toxic change, nucleated RBCs, spherocytes, hemoparasites, and lymphoblasts, were not predictably identified by ERP. Conclusions: ERP interpretation of canine and feline blood smears should be used cautiously and should not replace evaluation by a veterinary diagnostic laboratory.     

Hematologic improvement in dogs with parvovirus infection treated with recombinant canine granulocyte‐colony stimulating factor

Duffy A., Dow S., Ogilvie G., Rao S., Hackett T. Hematologic improvement in dogs with parvovirus infection treated with recombinant canine granulocyte‐colony stimulating factor. J. vet. Pharmacol. Therap. doi: 10.1111/j.1365‐2885.2009.01153.x. Previously, dogs with canine parvovirus‐induced neutropenia have not responded to treatment with recombinant human granulocyte‐colony stimulating factor (rhG‐CSF). However, recombinant canine G‐CSF (rcG‐CSF) has not been previously evaluated for treatment of parvovirus‐induced neutropenia in dogs. We assessed the effectiveness of rcG‐CSF in dogs with parvovirus‐induced neutropenia with a prospective, open‐label, nonrandomized clinical trial. Endpoints of our study were time to recovery of WBC and neutrophil counts, and duration of hospitalization. 28 dogs with parvovirus and neutropenia were treated with rcG‐CSF and outcomes were compared to those of 34 dogs with parvovirus and neutropenia not treated with rcG‐CSF. We found that mean WBC and neutrophil counts were significantly higher (P < 0.05) in the 28 dogs treated with rcG‐CSF compared to disease‐matched dogs not treated with rcG‐CSF. In addition, the mean duration of hospitalization was reduced (P = 0.01) in rcG‐CSF treated dogs compared to untreated dogs. However, survival times were decreased in dogs treated with rcG‐CSF compared to untreated dogs. These results suggest that treatment with rcG‐CSF was effective in stimulating neutrophil recovery and shortening the duration of hospitalization in dogs with parvovirus infection, but indicate the need for additional studies to evaluate overall safety of the treatment.