Performance evaluation of the Sysmex XN-1000V in side-by-side comparison with the Siemens ADVIA 120 and manual methods for healthy CD Sprague-Dawley rats and CD-1 mice.

BACKGROUND: The Sysmex XN-1000V automated hematology analyzer with multispecies software was released in June 2017 for use in research laboratories. Laser light, impedance, fluorescent staining, and fluorescent flow cytometry are used to analyze whole blood for CBC, reticulocyte counts, and WBC counts, including a 5-part differential leukocyte analysis. OBJECTIVES: A side-by-side comparison of the Sysmex XN-1000V with the Siemens ADVIA 120 in analyzing blood from healthy mice and rats will provide insight into the performance of the new analyzer and its capabilities for use in drug development studies. Method correlation analyses on normal mouse and rat hematology data collected with both analyzers and manual reference methods will help determine the reliability of the data produced using the Sysmex XN-1000V analyzer. METHODS: Whole blood samples collected in K2 EDTA from healthy CD-1 mice and CD Sprague-Dawley rats were analyzed in parallel with the XN-1000V and ADVIA 120 analyzers. Male and female mice, approximately 6-9 weeks old, and male and female rats, approximately 7-9 weeks old, were included in this study. Manual reference methods for WBC differential leukocyte analysis and packed cell volume (PCV) measurements were also performed. EP Evaluator version 11.2 (Data Innovations LLC, South Burlington, VT, USA) was used for method comparison statistical analysis. RESULTS: Most hematologic parameters for naïve mice and rats achieved correlation in the fair to excellent range, with the majority showing very good to excellent correlation with low biases (<11.0%) for cohorts analyzed separately and when cohort data were combined. CONCLUSIONS: The Sysmex XN-1000V Hematology Analyzer provided comparable results to those obtained from the Siemens ADVIA 120. We found the Sysmex XN-1000V Hematology Analyzer to be acceptable for use in drug development studies for rats and mice.

Reference intervals for reticulocyte indices, immature reticulocyte fraction, and the percentage of hypochromic red blood cells in adult large breed dogs using the ADVIA 2120 hematology analyzer.

Reticulocyte indices are used to characterize anemia, including the identification of regeneration. In people, the immature reticulocyte fraction (IRF), percentage of hypochromic red blood cells (%HYPO-RBC), and other reticulocyte indices have been used as earlier indicators of erythropoiesis and as valuable monitoring tools in the assessment of various therapies. The reference intervals (RI) of the IRF and %HYPO-RBC have not been reported in dogs. The objective of this study was to establish RIs for novel variables (IRF, %HYPO-RBC, and CH-delta) and assess RIs for more commonly reported reticulocyte indices in healthy dogs. RIs were calculated from blood results retrospectively collected from 106 client-owned healthy dogs at the time of induction into a blood donor program using the ADVIA 2120 hematology analyzer (Siemens Healthcare Diagnostics). For the calculation of RIs, appropriate tests were applied for outlier detection and normality assessment. For variables normally distributed, RIs and their respective 90% confidence intervals (CIs) were calculated using parametric methods, while for variables not normally distributed, robust methods were used and bootstrapping for calculating the 90% CIs. The following RIs were established: reticulocyte hemoglobin content (CHr) 24.5-28 pg, mean reticulocyte volume (MCVr) 85.9-99.3 fL, mean corpuscular hemoglobin concentration of reticulocytes (CHCMr) 271.0-306.3 g/L, IRF 10.4%-43.5%, CH-delta 0.5-4.3 pg, and percentage of hypochromic red blood cells (%HYPO-RBC) 0.10%-0.80%. The results of this study provide RIs for novel reticulocyte variables. Further studies are required to determine the clinical utility of IRF, %HYPO-RBC, and CH delta as early indicators of erythropoietic activity in canine patients.

Pre-analytical and analytical variability of reticulocyte counts in dogs.

BACKGROUND: Automated fluorescence-based haematology analysers are now available for reticulocyte enumeration in veterinary medicine, but manual counting is still largely used. This study aimed to evaluate potential sources of analytical and pre-analytical errors when performing automated and manual counts. METHODS: Automated and two-operator double-blind manual reticulocyte counts were performed on 15 blood samples. The intra-assay variation of the automated and manual counts and the interoperator variation in the manual counts were then calculated. In addition, the effects of storage were evaluated using samples refrigerated at 4°C or stored at room temperature for 2, 4, 12, 24, 48 or 72 hours after sampling. RESULTS: Intra-assay coefficients of variation were lower for automated counts than for manual counts. Comparison between automated and mean total manual reticulocyte count showed no significant differences. In both refrigerated samples and those stored at room temperature, an increase in reticulocyte count was recorded only after 72 hours. Staining artefacts occurred only in one stored sample counted manually. LIMITATIONS: The presence of cytoplasmic particles other than RNA can cause misinterpretation of cells, leading to an erroneous reticulocyte count. CONCLUSION: The use of an automated analyser is preferable for reticulocyte enumeration in dogs. Common storage conditions seem to minimally affect reticulocyte evaluation; however, it is recommended to perform the analysis as soon as possible after sampling.

Clinical utility of immature reticulocyte fraction for identifying early red blood cell regeneration in anemic dogs.

BACKGROUND: Evaluating regeneration is essential for the classification and differential diagnosis of anemia in dogs. Early detection of regeneration is challenging in anemic dogs. OBJECTIVES: This study assessed the value of immature reticulocyte fraction (IRF) in differentiating preregenerative anemia (PRA) from nonregenerative anemia (NRA) in dogs. ANIMALS: Ninety-four dogs: 49 controls and 45 with anemia. METHODS: Case-control study. Fractions of low-, medium- (MFR), and high-fluorescence reticulocytes (HFR), were measured using the ADVIA 2120i hematology analyzer. The IRF was calculated as the sum of percentages of MFR and HFR. Data from dogs with regenerative anemia (RA, n = 19), PRA (n = 11), and NRA (n = 15) were retrospectively analyzed. The value of IRF was compared with reticulocyte production index (RPI) using the receiver operating characteristic (ROC) curve. RESULTS: The median of IRF was significantly higher in dogs with RA (46.5%; range, 40.9-53.6%; P < .001) and PRA (40.6%; range, 27.7-47.1%; P = .01) than in controls (22.1%; range, 16.9-29.3%). The IRF in dogs with PRA showed no difference compared to dogs with RA (P > .99) but was higher than dogs with NRA (18.7%; range, 8.8-24%; P = .00). The area under the ROC curve of IRF was superior to that of RPI (0.897 vs 0.818, P = .00) in differentiating dogs with PRA from NRA. CONCLUSIONS AND CLINICAL IMPORTANCE: The IRF is a reliable variable for detecting early regeneration in anemic dogs without reticulocytosis. The study suggests that the measurement of IRF could be useful in classifying anemic dogs.

Spurious, marked leukocytosis in 2 cats with Heinz body hemolytic anemia.

Two domestic shorthair cats were presented with anorexia and dehydration following ingestion of caramelized onions. Shared key findings from a CBC (ADVIA 2120), serum biochemistry, and urinalysis included a spurious, marked leukocytosis with discordant basophil (BASO) channel and peroxidase channel WBC counts, normal manual leukocyte counts, mild, non-regenerative anemia with discrepancies between automated and manual reticulocyte counts, an abundance of large Heinz bodies (HBs), and highly irregular scattergrams. Case 1 also demonstrated a markedly elevated mean corpuscular hemoglobin concentration (MCHC) and discrepancies between RBC hemoglobin indices. Spurious leukocyte results were confirmed through re-analysis of samples (including the acquisition of a new sample, use of an alternate analyzer (Sysmex XT-2000iV; Case 1 only), and evaluation of scattergrams and blood films (Cases 1 and 2). Repeatedly discrepant reticulocyte counts were also identified. In both cases, the erroneous BASO WBC counts, discrepancies in reticulocyte counts and RBC indices, and atypical scattergrams were interpreted to result from various effects of the HBs. These cases emphasize the importance of reviewing blood films, interpreting scattergrams, and the usefulness of duplicate methods for determining various measurands on hematology analyzers.

Correlação entre as contagens de reticulócitos manual e automática em amostras de felinos anêmicos / Correlation between manual and automatized values of reticulocyte count in anemic feline samples

O objetivo do presente estudo foi correlacionar os valores de reticulócitos pontilhados e agregados obtidos por metodologia manual com a metodologia automática de contagem de reticulócitos totais em amostras de sangue de gatos anêmicos, analisados em um contador hematológico com citometria de fluxo. Para isso, 40 amostras de sangue de pacientes felinos anêmicos, independentemente de idade e sexo, foram utilizadas para a determinação das contagens absolutas de reticulócitos totais pela metodologia automatizada por citometria de fluxo fluorescente e pela técnica manual com corante supravital, em duplicata. Na contagem manual, houve a discriminação entre reticulócitos pontilhados e agregados. Para a correlação entre os métodos, foi realizada a análise de regressão de Passing-Bablok. A média do hematócrito dos gatos foi de 15,25%, tendo a maioria dos gatos (32,5%) apresentado anemia moderada (hematócrito = 17,81%). Como resultados, a análise de regressão demonstrou que a correlação entre a contagem absoluta total automática foi superior à contagem manual de reticulócitos agregados (rho= 0,71; P<0,001) do que a contagem absoluta de reticulócitos pontilhados (rho= 0,68; P<0,001). Os resultados apresentados sugerem que a contagem de reticulócitos total absoluta realizada pelo analisador hematológico ProCyte Dx em gatos anêmicos se refere à contagem absoluta de reticulócitos. Dessa maneira, recomenda-se que os valores possam ser utilizados para a avaliação imediata da condição hematológica de gatos anêmicos.(AU)

The aim of this study was to correlate the punctate and aggregated reticulocytes values obtained by manual methodology and the automatic reticulocyte count in 40 blood samples from anemic cats. Total reticulocyte absolute counts were determined by automated fluorescence flow cytometry and manual methods in 40 blood samples obtained from anemic cats. The manual count was obtained by supravital stain in duplicate to each sample and the reticulocyte morphology were discriminated between punctate and aggregates reticulocytes. Passing-Bablok regression analysis was utilized to compare the methods. Most samples were from anemic cat (15,25%) and the hematocrit mean was 17,81%. Regression analysis showed that the correlation between the absolute total automatic counts is higher with aggregated reticulocytes (rho= 0,71; P< 0,001) than with absolute punctate reticulocytes counts (rho= 0, 68, P< 0.001). Results suggest that the ProCyte Dx reticulocytes count in anemic cats is correlated with aggregate reticulocyte count. Thus, the greater amount of RNA and organelles in aggregate reticulocytes generates a cellular complexity and, therefore, greater impregnation of the dye in an automatic count. Thus, the values obtained by the hematologic instrument can be used for the immediate evaluation of the hematological condition in anemic cats.(AU)

A comparison of manual counting of rabbit reticulocytes with ADVIA 2120i analyzer counting.

We compared manual counting of reticulocytes in rabbits with automatic counting using an ADVIA 2120i analyzer. Reproducibility and the influence of different anticoagulants (EDTA and Li-heparin) were also examined. Blood samples of 331 rabbits (method comparison, n = 289; reproducibility, n = 33; comparison of anticoagulants, n = 9) were tested. The reticulocyte numbers of each specimen were manually determined twice for method comparison. Passing-Bablok regressions, Bland-Altman plots, and the coefficient of variation (CV) were used to evaluate statistical significance. Good correlation (rs = 0.81) was observed between manual reticulocyte counting (groups 1-4) and the ADVIA 2120i. Quantification with the ADVIA 2120i was reproducible for relative reticulocyte numbers (EDTA, CV = 4.24%; Li-heparin, CV = 3.63%) and absolute reticulocyte numbers (EDTA, CV = 5.64%; Li-heparin, CV = 3.81%). The absolute and relative reticulocyte numbers were significantly higher in Li-heparin samples than in EDTA samples (absolute, p = 0.009; relative, p = 0.016). The ADVIA 2120i is suitable for counting reticulocytes in rabbit blood samples, but reticulocyte numbers are higher by manual counting than by ADVIA 2120i counting. Therefore, microscopic confirmation of quantifications is recommended when high numbers of reticulocytes are observed. The anticoagulant of choice is EDTA.

Diagnostic performances of manual and automated reticulocyte parameters in anaemic cats.

Objectives The objective of this study was to evaluate the diagnostic performances of manual and instrumental measurement of reticulocyte percentage (Ret%), reticulocyte number (Ret#) and reticulocyte production index (RPI) to differentiate regenerative anaemia (RA) from non-regenerative anaemia (NRA) in cats. Methods Data from 106 blood samples from anaemic cats with manual counts (n = 74; 68 NRA, six RA) or instrumental counts of reticulocytes (n = 32; 25 NRA, seven RA) collected between 1995 and 2013 were retrospectively analysed. Sensitivity, specificity and positive likelihood ratio (LR+) were calculated using either cut-offs reported in the literature or cut-offs determined from receiver operating characteristic (ROC) curves. Results All the reticulocyte parameters were significantly higher in cats with RA than in cats with NRA. All the ROC curves were significantly different ( P <0.001) from the line of no discrimination, without significant differences between the three parameters. Using the cut-offs published in literature, the Ret% (cut-off: 0.5%) was sensitive (100%) but not specific (<75%), the RPI (cut-off: 1.0) was specific (>92%) but not sensitive (<15%), and the Ret# (cut-off: 50 × 10³/µl) had a sensitivity and specificity >80% and the highest LR+ (manual count: 14; instrumental count: 6). For all the parameters, sensitivity and specificity approached 100% using the cut-offs determined by the ROC curves. These cut-offs were higher than those reported in the literature for Ret% (manual: 1.70%; instrumental: 3.06%), lower for RPI (manual: 0.39; instrumental: 0.59) and variably different, depending on the method (manual: 41 × 10³/µl; instrumental: 57 × 10³/µl), for Ret#. Using these cut-offs, the RPI had the highest LR+ (manual: 22.7; instrumental: 12.5). Conclusions and relevance This study indicated that all the reticulocyte parameters may confirm regeneration when the pretest probability is high, while when this probability is moderate, RA should be identified using the RPI providing that cut-offs <1.0 are used.

Anaemia in pet rabbits: causes, severity and reticulocyte response.

The objective of the study was to determine the causes and the severity of anaemia in pet rabbits (Oryctolagus cuniculus), to classify anaemia and to compare the reticulocyte counts from healthy and anaemic rabbits. Over a time period of 11 years (2000-2011) a retrospective and prospective study of 223 pet rabbits was performed. Based on the clinic's own reference range for healthy pet rabbits (packed cell volume [PCV] levels 0.33-0.45 l/l), animals with a PCV level below 0.33 l/l were considered anaemic. Anaemia was mostly caused by inflammation (65/223, 29 per cent) and bleeding (54/223, 24 per cent). Seven per cent (15/223) of the rabbits suffered from renal diseases and one rabbit got diagnosed with haemolysis caused by liver lobe torsion. In 14 per cent (32/223) of the rabbits more than one underlying pathomechanism, like inflammation and bleeding, was diagnosed as possible cause of anaemia. In 25 per cent (56/223) of the anaemic rabbits no cause was found. Most anaemias were mild (156/223, 70 per cent). Moderate (43/223, 19 per cent) or severe (24/223, 11 per cent) anaemia was diagnosed more rarely. Anaemic rabbits showed similar reticulocyte counts to healthy rabbits with no significant difference. Therefore, a differentiation of regenerative and non-regenerative anaemia was not possible.

Spurious reticulocyte profiles in a dog with babesiosis.

A 9-year-old, female Maltese dog was referred to the Veterinary School of Toulouse with a 2-day history of anorexia and weakness. On clinical examination, the dog had hyperthermia (39.7°C), abdominal discomfort, and polypnea. Significant laboratory findings included pigmenturia, hyperbilirubinemia, hypercreatininemia, hyperfibrinogenemia, abnormal Snap canine pancreas-specific lipase, and pancytopenia with a nonregenerative anemia. A peripheral blood smear revealed numerous intraerythrocytic large Babesia but no polychromasia. There was a discrepancy between the absolute automated reticulocyte count (Sysmex reticulocyte count: 60 × 109 /L; RI 19.4-150.1 × 109 /L) and the manual reticulocyte count (3.6 × 109 /L) as well as the absence of polychromasia. The optical red blood cell scattergram showed an abnormal isolated reticulocyte cluster at the location of low-fluorescence ratio cells. These findings were interpreted as erythrocytes parasitized by large Babesia. The discrepancy between the Sysmex reticulocyte count and the manual reticulocyte count has been reported previously in people with falciparum malaria and numerous intra-erythrocytic Plasmodium falciparum organisms. This spurious reticulocyte profile and reticulocyte count were observed with the Sysmex XT-2000iV and the ProCyte using the same fluorescent dye polymethine but not with the LaserCyte using new methylene blue which does not stain Babesia organisms on a blood smear performed for manual reticulocyte counting.

Spurious reticulocyte profiles in dogs with large form babesiosis: a retrospective study.

BACKGROUND: Erroneously high reticulocyte counts (pseudoreticulocytosis) have been reported in dogs with leukemia. Pseudoreticulocytosis and an abnormal reticulocyte profile were observed in a dog with large form babesiosis presented at our institution. OBJECTIVES: The aims of this retrospective study were to determine if dogs with babesiosis and other dogs had abnormal reticulocyte profiles, and to correlate these profiles with the primary diagnosis. METHODS: All canine CBCs obtained with the Sysmex XT-2000iV or Procyte DX were reviewed. Cases of large form babesiosis were identified and their reticulocyte dot plots were analyzed. Dogs with abnormal reticulocyte profiles but without microscopically apparent intraerythrocytic Babesia piroplasms were identified. The reticulocyte profiles and fluorescence ratios of dogs with and without babesiosis were compared. RESULTS: Twenty of 92 dogs with babesiosis had abnormal reticulocyte profiles, including 8 with a separation between the reticulocyte and mature RBC plots or a continuum of reticulocytes from the RBC plot but with a higher density of dots in the middle of the "comet tail" than in the left quarter of the dot plot. Thirteen of 6980 dogs without Babesia on the blood smear had abnormal reticulocyte profiles, including 3 with leukemia. The medium-fluorescence reticulocyte ratios tended to be higher in dogs with babesiosis and abnormal dot plots than in other dogs, whereas the high-fluorescence ratio was higher in one dog with leukemia. CONCLUSION: Abnormal reticulocyte dot plots and atypical reticulocyte fluorescence ratios may occur in dogs with babesiosis and alert clinical pathologists to consider this diagnosis.

Evaluation of Iron Deficiency Using Reticulocyte Indices in Dogs Enrolled in a Blood Donor Program.

BACKGROUND: People donating blood more than twice annually are at risk of developing iron deficiency. Little is known about the iron status of dogs enrolled in blood donor programs. HYPOTHESIS: Dogs donating blood ≥6 times annually will show evidence of iron deficiency based on their reticulocyte indices. ANIMALS: Thirteen dogs enrolled in a blood donor program donating ≥6 times over the preceding 12 months and 20 healthy nondonor control dogs. METHODS: Prospective observational study. Mature red blood cell (RBC) indices, reticulocyte indices, serum iron, serum ferritin, and total iron-binding capacity (TIBC) were compared between groups. RESULTS: Packed cell volume (median 47%, range 40-52%, P < .01), hematocrit (median 46.4%, range 40.3-52.5%, P < .01), and reticulocyte count (median 16,000/µL, range 9,000-38,000/µL, P < .01) were significantly lower in the blood donor dogs. No statistically significant differences were noted in the mature RBC indices between groups. Both reticulocyte mean corpuscular volume (median 88.8 fL, range 83.4-95.5 fL, P = .03) and reticulocyte hemoglobin content (median 24.6 pg, range 23.1-26.6 pg, P < .01) were significantly lower in the blood donor group. Serum iron and ferritin were similar between groups; however, TIBC was significantly higher in the control group (median 403 µg/dL, range 225-493 µg/dL, P = .02). CONCLUSIONS: The findings in dogs donating ≥6 times annually suggest the presence of iron-deficient erythropoiesis in this population.

Diagnosis of Disorders of Iron Metabolism in Dogs and Cats.

Iron is an essential element and is used by every cell in the body. This article summarizes iron metabolism and disorders associated with iron metabolism in dogs and cats. The diagnostic tests currently in use for assessing iron status are discussed.

Analytic errors in Sysmex-generated hematology results in blood from a dog with chronic lymphocytic leukemia.

A blood sample from a 14-year-old dog was submitted to the veterinary diagnostic laboratory of the University of Milan for marked leukocytosis with atypical cells. A diagnosis of chronic T-cell lymphocytic leukemia (CLL) was made based on blood smear evaluation and flow cytometric phenotyping. A CBC by Sysmex XT-2000iV revealed a moderate normocytic normochromic anemia. Red blood cells counted by optic flow cytometry (RBC-O) resulted in a higher value than using electrical impedance (RBC-I). The relative reticulocyte count based on RNA content and size was 35.3%, while the manual reticulocyte count was < 1%. The WBC count of 1,562,680 cells/µL was accompanied by a flag. Manual counts for RBC and WBC using the Bürker chamber confirmed the Sysmex impedance results. Finally the manual PCV was lower than HCT by Sysmex. While Sysmex XT can differentiate between RBC and WBC by impedance, even in the face of extreme lymphocytosis due to CLL, RBC-O can be affected by bias, resulting in falsely increased RBC and reticulocyte numbers. Overestimation of RBC-O may be due to incorrect Sysmex classification of leukemic cells or their fragments as reticulocytes. This phenomenon is known as pseudoreticulocytosis and can lead to misinterpretation of regenerative anemia. On the other side PCV can be affected by bias in CLL due to the trapping of RBC in the buffy coat, resulting in a pink hue in the separation area. As HGB concentration is not affected by flow cytometric or other cell-related artifacts it may represent the most reliable variable to assess the degree of anemia in cases of CLL.

Effects of racing on reticulocyte concentrations in Greyhounds.

BACKGROUND: Greyhounds have several hematologic variables that are outside of the respective reference intervals of other dog breeds. In addition, increases in HCT, total protein and HGB concentration, and RBC and WBC counts occur immediately after exercise; these values return to resting values within a few hour after racing. OBJECTIVE: This study evaluated the effects of exercise on the concentration of reticulocytes in circulating blood in racing Greyhounds. We hypothesized that reticulocyte numbers are significantly increased immediately after a race, and return to baseline within one to 2 h postrace. METHODS: Fifty actively racing Greyhounds at the Wheeling Island Racetrack and Casino were included in the study. Samples were collected by jugular venipuncture one day prior to racing at the kennel (resting), immediately after racing, and one to 2 h after the race (recovery). Reticulocyte counts were determined with an IDEXX ProCyte Dx Hematology Analyzer (IDEXX Laboratories, Inc., Westbrook, ME, USA). Due to a nonparametric distribution, the results were statistically compared using the Friedman test. RESULTS: Reticulocyte concentrations were significantly different among the 3 sample collection times (P < .0001). There was a significant increase in reticulocyte concentration immediately after racing (P < .001); one to 2 h after racing, the reticulocyte numbers decreased significantly (P < .001) to counts comparable to resting samples. CONCLUSION: The increase in reticulocyte concentration is probably related to splenic contraction secondary to the release of catecholamines, although premature bone marrow release could also account for these changes. Thus, it is important to consider a Greyhound's activity and degree of excitement when interpreting selected hematologic data in a clinical setting.

In-clinic laboratory diagnosis of canine babesiosis (Babesia canis canis) for veterinary practitioners in Central Europe.

OBJECTIVE: Haematological changes in dogs and climatic conditions favourable for the vector may assist in the quick in-house diagnosis of canine babesiosis. MATERIAL AND METHODS: Blood samples from 358 dogs suspected to have canine babesiosis were evaluated. The diagnosis was confirmed in 113 dogs by detection of Babesia canis by microscopic examination of a stained blood smear using the concentration line technique. RESULTS: Thrombocytopenia was present in all 113 dogs. Red blood cell count, packed cell volume and haemoglobin values were below the reference range in 62.8%, 61.1% and 46.0% of affected dogs, respectively. An increased reticulocyte count was apparent in five Babesia canis -positive dogs. Leukopenia, lymphopenia, neutropenia and monocytosis were present in 54.9%, 47.8%, 30.4% and 6.5% of the dogs, respectively. Evaluating haematological parameters by CART-analysis revealed a predictive model (accuracy= 93.5%) for canine babesiosis, when using the leucocyte, thrombocyte, and reticulocyte count. Climatic conditions present at the most probable time of Babesia canis- infection accounted for biseasonal occurrence. Changes of climatic factors during the year influence the vector activity and in conclusion should highlight babesiosis in the ranking of differentials for veterinarians. CONCLUSION: The results demonstrate that a tentative diagnosis of canine babesiosis can be made based on typical haematological changes. The results recorded match well with the seasonality of the tick vector and were confirmed here by the month of sample submission.

Evaluation of the automated hematology analyzer Sysmex XT-2000iV ™ compared to the ADVIA ® 2120 for its use in dogs, cats, and horses. Part II: Accuracy of leukocyte differential and reticulocyte count, impact of anticoagulant and sample aging.

The automated laser-based hematology analyzer Sysmex XT-2000iV™ provides a 5-part differential count and specific cytograms that are of great interest for large veterinary laboratories. The aim of the study was to validate the Sysmex XT-2000iV compared to the laser-based hematology analyzer ADVIA® 2120 and manual differential in dogs, cats, and horses as well as the impact of anticoagulant (heparin, ethylenediamine tetra-acetic acid [EDTA], and citrate) and storage at 22°C and 4°C. Consecutive fresh K(3)-EDTA blood samples from 216 cats, 314 dogs, and 174 horses were included. The impact of anticoagulant and sample storage was assessed in specimens obtained from an additional 9 cats, 10 dogs, and 10 horses. Agreement between both analyzers was excellent to good except for monocytes and canine reticulocytes. Spearman rank correlation coefficients (r (s)) between Sysmex XT-2000iV and manual differential were good to fair and ranged from 0.91 (cat lymphocytes) to 0.44 (cat monocytes). Hematocrit value (Hct), mean corpuscular hemoglobin (MCH), MCH concentration (MCHC; all: P < 0.001), and mean corpuscular volume (MCV; P < 0.01) were higher in canine citrated blood compared to heparin and EDTA. In cats, lymphocytes and monocytes were lower in heparinized blood compared to EDTA (P < 0.05), whereas in horses no significant effect was seen. Regarding storage time and temperature, white and red blood cell counts, hemoglobin, and MCH were stable. Hct, MCV, and MCHC were influenced by erythrocyte swelling. Differential count remained stable for 24 hr (22°C) and nearly 72 hr (4°C) except for monocytes. The overall performance of the Sysmex XT-2000iV was excellent and compared favorably with that of the ADVIA 2120. A special strength was the excellent detection of feline eosinophils.

Diagnostic accuracy of using erythrocyte indices and polychromasia to identify regenerative anemia in dogs.

OBJECTIVE: To determine diagnostic accuracy of using erythrocyte indices and polychromasia to identify regenerative anemia in dogs. DESIGN: Retrospective and prospective cross-sectional study. ANIMALS: 4,521 anemic dogs. PROCEDURES: CBC results obtained between July 2002 and July 2008 by use of an automated laser-based flow cytometric hematology analyzer from dogs with Hct values ≤ 35% were retrieved. Sensitivity, specificity, accuracy, and predictive values of using erythrocyte indices and polychromasia to identify regeneration were determined, with a reticulocyte count > 65,000 reticulocytes/µL considered the gold standard. Similarly, 134 blood samples from anemic dogs were analyzed prospectively with an in-house electrical impedance analyzer. RESULTS: Of 4,387 dogs with samples analyzed retrospectively, 1,426 (32.5%) had regenerative anemia. Of these, 168 (11.8%) had macrocytic hypochromic anemia. High mean cell volume and low mean cell hemoglobin concentration had low sensitivity (11%), high specificity (98%), and moderate accuracy (70%) when used to identify regenerative anemia. Use of polychromasia alone had an accuracy of 77%, and use of polychromasia combined with a high RBC distribution width (RDW) had an accuracy of 79%. Results obtained with the in-house analyzer were similar. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that most regenerative anemias in dogs were not macrocytic hypochromic. Polychromasia, with or without high RDW, was a more accurate indicator than other erythrocyte indices of regenerative anemia. To avoid a false diagnosis of nonregenerative anemia, a blood smear should be evaluated in anemic dogs when a reticulocyte count is not available.