Standardization of reticulocyte counts in the athlete biological passport: A practical update.

INTRODUCTION: The athlete biological passport monitors blood variables over time to uncover blood doping. With the phasing in of a new series of blood analyzers, the Sysmex XN series, it was necessary to examine the comparability of results with the previously employed XT/XE series. A previous comparison between XN and XT/XE series suggested a small but significant bias between the two instruments in the measurements of RET%. Here, we examined the comparability of RET% on the XN and XT/XE platform using data collected over the first year since the transition. METHODS: The comparability of results obtained from XN and XT/XE instruments was assessed using three datasets: (i) 767 blood samples measured on both instrument series in 22 WADA-accredited laboratories, (ii) 27 323 samples measured on either instrument across 31 laboratories, and (iii) 119 clinical samples and 110 anti-doping samples measured on both instruments in a single laboratory. RESULTS: Analysis of the three datasets confirms the previous observation of a bias toward higher RET% values for samples measured on Sysmex XN instruments compared with the XT/XE series. Using data across a larger number of XN instruments and a larger athlete population, the current work suggests that the bias is proportional and slightly higher than previously observed across most of the range RET% values. CONCLUSION: A model is proposed for the comparison of data across XN and XT/XE technologies whereby the instrument bias increases proportionally with RET% measured on Sysmex XN Series, but where the rate of increase is negatively related to IRF%.

Reference intervals of automated reticulocyte count and immature reticulocyte fraction in a pediatric population.

INTRODUCTION: Reticulocytes are erythroid precursors that develop into mature erythrocytes, and they are an important tool to assess erythropoietic activity, as their count indicates the balance between the cells released from the bone marrow, their stage of maturity, and their rate of development into mature erythrocytes. Considering the described biological variability of the absolute reticulocyte count (ARC) and the immature reticulocyte fraction (IRF) and the limited information available on these hematological parameters in children, this study determined the reference intervals (RIs) of these parameters in a healthy pediatric population. METHODS: A retrospective, observational, and analytical study was designed to establish RIs for the ARC and the IRF according to age and sex. An indirect sampling method was applied to a mixed database of complete blood counts from children aged 2 months to 18 years, using the truncated maximum likelihood indirect method for reference interval estimation. Percentiles were calculated to obtain bimodal RIs. RESULTS: From a total of 190,812 samples, 6,814 were selected. Gender stratification was not necessary for the ARC and the IRF but they required partitioning into six and two age groups, respectively. CONCLUSION: This study determined, by an indirect sampling method, RIs for the ARC and the IRF in a pediatric population according to age and sex.

Neonatal Reference Intervals for the Complete Blood Count Parameters MicroR and HYPO-He: Sensitivity Beyond the Red Cell Indices for Identifying Microcytic and Hypochromic Disorders.

OBJECTIVE: To create neonatal reference intervals for the MicroR and HYPO-He complete blood count (CBC) parameters and to test whether these parameters are sensitive early markers of disease at early stages of microcytic/hypochromic disorders while the CBC indices are still normal. STUDY DESIGN: We retrospectively collected the CBC parameters MicroR and HYPO-He, along with the standard CBC parameters, from infants aged 0-90 days at Intermountain Healthcare hospitals using Sysmex hematology analyzers. We created reference intervals for these parameters by excluding values from neonates with proven microcytic disorders (ie, iron deficiency or alpha thalassemia) from the dataset. RESULT: From >11 000 CBCs analyzed, we created reference intervals for MicroR and HYPO-He in neonates aged 0-90 days. The upper intervals are considerably higher in neonates than in adults, validating increased anisocytosis and polychromasia among neonates. Overall, 52% of neonates with iron deficiency (defined by reticulocyte hemoglobin equivalent <25 pg) had a MicroR >90% upper interval (relative risk, 4.14; 95% CI, 3.80-4.53; P < .001), and 68% had an HYPO-He >90% upper interval (relative risk, 6.64; 95% CI, 6.03-7.32; P < .001). These 2 new parameters were more sensitive than the red blood cell (RBC) indices (P < .001) in identifying 24 neonates with iron deficiency at birth. CONCLUSIONS: We created neonatal reference intervals for MicroR and HYPO-He. Although Sysmex currently designates these as research use only in the US, they can be measured as part of a neonate's CBC with no additional phlebotomy volume or run time and can identify microcytic and hypochromic disorders even when the RBC indices are normal.

Estudio de la ferropenia en el laboratorio clínico / Laboratory evaluation of iron deficiency

El hierro es un elemento químico esencial para todos los organismos vivos, necesario para un amplio espectro de funciones metabólicas vitales. La exploración del metabolismo del hierro puede ser difícil en algunas situaciones, tales como en el paciente con una enfermedad crónica, por la respuesta de los biomarcadores frente a la inflamación. En los últimos años el laboratorio clínico ha incorporado nuevos biomarcadores a los tradicionalmente empleados, con el fin de mejorar su contribución al diagnóstico y seguimiento de la ferropenia. Se ha realizado una búsqueda sistemática de la evidencia científica publicada en los diez últimos años para los siguientes biomarcadores: el diagnóstico morfológico de la sangre periférica, los índices hematimétricos, y las concentraciones plasmáticas de transferrina (y sus índices), ferritina, receptor soluble de transferrina y hemoglobina, en la ferropenia. Se emiten recomendaciones para estos biomarcadores en relación al diagnóstico y manejo del paciente ferropénico

Iron is an essential chemical element for all living organisms, and is required for a broad spectrum of vital metabolic functions. The study of iron metabolism can be challenging in some situations, such as in patients with chronic diseases, due to the effect of inflammation response. In recent years, clinical laboratory research has introduced new biomarkers to those commonly used, with the aim of improving the diagnosis and management of iron deficiency. In this work, a systematic search of the scientific evidence reported during the last decade has been made for the following biomarkers: morphological diagnosis of peripheral blood, hematimetric indices, and plasma concentrations of transferrin (and its indices), ferritin, transferrin receptor, and haemoglobin, in iron deficiency. Recommendations are made for these biomarkers related to the diagnosis and management of the iron-deficient patient

Interferents of Automated Reticulocyte Analysis Integrated with Relevant Clinical Cases.

BACKGROUND: Reticulocyte count (RET) has been used for many years to estimate the erythropoietic activity of the bone marrow. Fully automated methods not only provide enhanced precision and accuracy, but also enable reliable measurements of mRNA content and cellular indices. However, problems still exist, such as interference. The aim of the present study was to investigate the interferents of Sysmex XN 9000 reticulocyte analysis and ensure the accuracy of the results. METHODS: We collected a total of 510 specimens from normal control patients and patients with various diseases including anemias, leukemias, infectious diseases, immune diseases, kidney disease, etc. Correlation of the agreement for reticulocytes between the new methylene blue (NMB) visual microscopy method and automated reticulocyte counting was evaluated by paired sample method according to the CLSI-ICSH document H44-A2-Methods for Reticulocyte Count. Blood smear microscopic examination was carried out on the disturbed samples, and the interferents were analyzed with the medical history, flagging algorithms, the warning information, and the microscopic examination. RESULTS: A total of 44 (8.6%) cases exhibited interference. The main interferents of spuriously high reticulocyte count were caused by parasites, such as malaria, as well as suspicious autofluorescence due to drugs, while the main interferents of spuriously low reticulocyte count were caused by RBC fragments. CONCLUSIONS: Detection of potential interferences may be accomplished through alarm information and flagging algorithms incorporated into the instrument and by examination of a blood film to ensure absence of relevant interferences.

Standardization of reticulocyte counts in the athlete biological passport.

INTRODUCTION: The percentage of circulating reticulocytes (RET%) is a useful marker of blood doping in the context of the Athlete Biological Passport (ABP). The viability of the ABP depends on the comparability of sample data obtained across multiple laboratories for a given athlete. With the recent introduction of a different technology for the measurement of reticulocytes, the goal of this study was to compare currently employed Sysmex XT/XE analyzers to the recently introduced Sysmex XN analyzer. METHODS: RET% differences were searched in two independent data sets, the first consisting of 95 369 RET% values coming from 29 laboratories located in five continents as part of routine testing for the ABP, the second from a targeted study involving 510 samples analyzed on both a Sysmex XT and XN analyzers by two different laboratories. RESULTS: A relatively small but significant bias of 0.27 ([0.22-0.35] 95% CI) for the first data set and 0.19% ([0.16-0.22] 95% CI) for the second data set was observed with Sysmex XN analyzers returning higher values than Sysmex XT/XE analyzers. This bias appears constant over most of the range of RET% measured in elite athletes. CONCLUSION: When RET% values are obtained for the same athlete with different technologies (XT/XE vs XN), an adjustment of RET% emanating from the XT/XE instruments through a decrease of 0.22% within the ABP calculated ranges appears to be sufficient to integrate the results from the two technologies.

Post-transfusion changes in serum hepcidin and iron parameters in preterm infants.

BACKGROUND: Packed red blood cell transfusion is common in preterm neonates. Hepcidin acts as a negative feedback iron regulator. Iron parameters such as immature reticulocyte fraction (IRF) and high-light-scatter reticulocytes (HLR) are used to clarify iron metabolism. Very little is known about the regulation of hepcidin in preterm infants because most reports have evaluated prohepcidin. The aim of this study was therefore to evaluate serum hepcidin and establish hematological parameters in preterm infants after transfusion. METHODS: The subjects consisted of 19 newborns (10 boys) with mean gestational age 29.1 ± 2.0 weeks, who had been transfused at the chronological age of 44.84 ± 19.61 days. Blood sample was collected before the transfusion and thereafter at 5 days and at 1 month. Serum hepcidin and other iron parameters were evaluated. RESULTS: Mean serum hepcidin before and 5 days after transfusion was significantly different (5.5 ± 5.1 vs 10 ± 7.9 ng/mL respectively, P = 0.005). IRF and % HLR were also decreased significantly, 5 days after transfusion (0.4 ± 0.2 vs 0.2 ± 0.1, P = 0.009; 1.4 ± 1.5% vs 0.5 ± 0.4%, P = 0.012, respectively). Changes in hepcidin 5 days after transfusion were correlated significantly with changes in mean corpuscular hemoglobin (ß, 0.13; SE, 0.05; P = 0.017), total iron binding capacity (ß, 3.74; SE, 1.56; P = 0.016) and transferrin (ß, 2.9, SE, 1.4; P = 0.039). CONCLUSIONS: Serum hepcidin concentration, along with IRF and HLR, are potentially useful in estimating pre- and post-transfusion iron status. Larger studies are needed to evaluate the sensitivity and specificity of hepcidin compared with ordinary iron parameters in premature infants.

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.

High Reticulocyte Count with Abnormal Red Blood Cell Morphology in Normal Wistar Rats after Garlic Administration.

Despite the high acceptability of Allium sativa (Garlic) as a remedy for many diseases as earlier stated by manyresearchers, previous studies have shown that chronic and unregulated consumption of garlic may result to intra vascularhaemolytic anaemia in rats. The present study was conducted to examine the effect of crude extract of garlic on microscopicstatus of red blood cells and some other haematological indices of normal albino rats. The animals were grouped into two;group 1 were normal animals treated with water while group 2 were normal animals administered 150mg/kg body weight ofcrude extract of garlic on alternate days for three weeks. At the end of three weeks treatment, blood samples obtained fromthe tail vein of the rats were used for haematological indices and erythrocyte morphology. The values obtained wereexpressed as Mean± SEM and compared using student t test. The results showed that there was no significant difference inthe PCV which was 43.20 ± 0.80% and 45.00 ± 0.36% in both control and experimental groups respectively. However, theRBCs were significantly decreased (P< 0.05) from 166.80 ± 3.44 x106 µL-1 in the control group to 87.80 ± 9.34 x106 µL-1 inthe treatment group. The percentage reticulocyte counts on the other hand significantly increased from 2.60±4.25% in controlgroup to 11.20± 16.4% in treated group. Fragmented RBCs with a lot of schistocytes with adequate platelets were seen onperipheral blood film of crude garlic treated rats as compared to control. Our results suggested intravascular haemolysis andnumerous reticulocytes on blood film confirmed our view on bone marrow response. The presence of schistocytes andacanthocytes may be an indication that the liver is involved in the observed effect.

Reticulocyte count and extended reticulocyte parameters by Mindray BC-6800: Reference intervals and comparison with Sysmex XE-5000.

INTRODUCTION: In this study, analytic performance (imprecision, carryover, time stability) and diagnostic efficiency of Mindray BC-6800 analyzer to quantify reticulocytes and extended reticulocyte parameters was evaluated. Moreover, reference intervals on adult population were determined. Results were compared with those obtained by Sysmex XE-5000 analyzer. METHODS: One hundred and eighty-four healthy adults of both sexes, and 368 subjects affected by various pathologic conditions (nutritional anemias before and after treatment, hemolytic and posthemorragic anemias, acute and chronic inflammations, malignancy under therapy, and beta thalassemia trait) were selected. RESULTS: Reference intervals were as follows: reticulocytes (×109 /L): 23.2-93.2; immature reticulocyte fraction: 0.015-0.14; mean reticulocyte hemoglobin equivalent (RHE) (pg): 30.9-35.7; mean reticulocyte volume (fL): 97.8-118. Imprecision on reticulocyte count at all concentrations was close to analytic goal based on within-subject biological variation. Carryover (2.3%) was negligible, and time-stability was excellent up to 8 hours. CONCLUSION: When compared with XE-5000, BC-6800 shows a good overall correlation on counting despite evidence of difference in the upper limit of reference intervals (93.2 vs 101.3). Comparison of diagnostic efficiency of extended parameters shows a good total agreement of RHE (91.6%).

Detection of erythropoietin misuse by the Athlete Biological Passport combined with reticulocyte percentage.

The sensitivity of the adaptive model of the Athlete Biological Passport (ABP) and reticulocyte percentage (ret%) in detection of recombinant human erythropoietin (rHuEPO) misuse was evaluated using both a long-term normal dose and a brief high dose treatment regime. Sixteen subjects received either 65 IU rHuEPO × kg-1 every second day for two weeks (normal-dose), 390 IU rHuEPO × kg-1 on three consecutive days (high-dose), or frequent placebo treatment for 13 days in a randomized, placebo-controlled, double-blind crossover design. Blood variables were measured 4, 11, and 25 days following treatment initiation. The ABP based on haemoglobin concentration ([Hb]) and OFF-hr score ([Hb] - 60 × âˆšret%) yielded atypical profiles following both normal-dose and high-dose treatment (0 %, 31 %, 13 % vs. 21 %, 33 %, 20 % at days 4, 11, and 25 after normal and high dose, respectively). Including ret% as a stand-alone marker for atypical blood profiles increased (P < 0.05) the sensitivity of the adaptive model at day 11 to 63 % and 67 % for normal-dose and high-dose rHuEPO administration, respectively. In conclusion, ~30 % of subjects injecting a normal-dose rHuEPO for two weeks or a high-dose rHuEPO for three days will present an atypical ABP profile. Including ret% as a stand-alone parameter improves the sensitivity two-fold. Copyright © 2015 John Wiley & Sons, Ltd.

El conteo automático de reticulocitos: una herramienta de uso diagnóstico, clínico e investigativo / Automated reticulocyte count: a tool for diagnostic, clinical and research use

Se revisan los antecedentes históricos del conteo de reticulocitos como determinación indispensable en el laboratorio de hematología para la evaluación de la actividad eritropoyética durante la clasificación, diagnóstico y monitoreo de la respuesta terapéutica en distintos trastornos y situaciones clínicas, principalmente en casos de anemias. Se describe el tránsito del tradicional método de conteo de reticulocitos manual al método automatizado y la integración de los parámetros reticulocitarios al hemograma automatizado actual; además, se analizan las desventajas del método de recuento manual y las ventajas del método automatizado, así como los principios de detección en que se basa el conteo electrónico de reticulocitos. Con relación a los parámetros reticulocitarios, se describe su medición, cálculo y unidades de medida; también se resalta la importancia de la fracción de reticulocitos inmaduros y del contenido de hemoglobina reticulocitaria como variables de mayor uso clínico e investigativo en la evaluación de la respuesta medular ante diversos trastornos clínicos y protocolos terapéuticos. Por último, se alude a la necesidad del conocimiento y empleo de las variables reticulocitarias en la práctica clínica de rutina por parte de los clínicos y especialistas en hematología.

The historical background of reticulocyte count is reviewed as an essential determination in the laboratory of hematology for the evaluation of erythropoietic activity during classification, diagnosis and monitoring of therapeutic response of different conditions and clinical situations are also reviewed, especially in anemia The transition from traditional manual reticulocyte counting method to automated method and integration of the reticulocyte parameters to current automated complete blood count are described. The disadvantages of manual method and the advantages of automated methods are cited, as well as detection principles in which electronic reticulocyte count is based. Regarding reticulocyte parameters, measurement, calculation and units are described. The importance of immature reticulocyte fraction and reticulocyte hemoglobin content as variables most clinical and research use in evaluating bone marrow response to various clinical disorders and therapeutic protocols are highlighted. Finally, the need for knowledge and use of reticulocyte variables in routine clinical practice by clinicians and hematologist is referred.

Clinical utility of reticulocyte parameters.

The reticulocyte count reflects the erythropoietic activity of bone marrow and is thus useful in both diagnosing anemias and monitoring bone marrow response to therapy. Automated flow-cytometric analysis has led to a significant advance in reticulocyte counting, by simultaneously providing additional parameters and indices such as the reticulocyte immature reticulocyte fraction (IRF), the reticulocyte volume, and the hemoglobin content and concentration. IRF has been proposed as an early marker of engraftment. Reticulocyte hemoglobin content is useful in assessing the functional iron available for erythropoiesis, and reticulocyte volume is a useful indicator when monitoring the therapeutic response of anemias.

Automated reticulocyte parameters for hereditary spherocytosis screening.

The laboratory diagnosis of hereditary spherocytosis (HS) is based on several screening and confirmatory tests; our algorithm includes clinical features, red blood cell morphology analysis and cryohaemolysis test, and, in case of positive screening, sodium dodecyl sulphate polyacrylamide gel electrophoresis as a diagnostic test. Using the UniCel DxH800 (Beckman Coulter) haematology analyser, we investigated automated reticulocyte parameters as HS screening tool, i.e. mean reticulocyte volume (MRV), immature reticulocyte fraction (IRF) and mean sphered cell volume (MSCV). A total of 410 samples were screened. Gel electrophoresis was applied to 159 samples that were positive for the screening tests. A total of 48 patients were diagnosed as HS, and seven were diagnosed as acquired autoimmune haemolytic anaemia (AIHA). Some other 31 anaemic conditions were also studied. From the receiver operating characteristic (ROC) curve analysis, both delta (mean cell volume (MCV)-MSCV) and MRV presented an area under the curve (AUC) of 0.98. At the diagnostic cut-off of 100 % sensitivity, MRV showed the best specificity of 88 % and a positive likelihood ratio of 8.7. The parameters IRF, MRV and MSCV discriminated HS not only from controls and other tested pathologies but also from AIHA contrary to the cryohaemolysis test. In conclusion, automated reticulocyte parameters might be helpful for haemolytic anaemia diagnostic orientation even for general laboratories. In combination with cryohaemolysis, they ensure an effective and time-saving screening for HS for more specialised laboratories.

Contagem de reticulócitos por citometria de fluxo utilizando acridine orange: validação de um novo protocolo / Flow cytometry reticulocyte counting using acridine orange: validation of a new protocol

Introduction: Currently, the reticulocyte counting is a challenge for clinical laboratories in Brazil, mainly for the ordinary ones, which still use the manual method. This method has some limitations, since it consists of a laborious method, time consuming, with low accuracy. Objectives: This study has developed and evaluated the performance of a New Laboratory Protocol for flow cytometry (FC) reticulocytes counting using acridine orange (AO) as dye, aiming to standardize a more precise, easy, fast implementation, and low cost protocol. After standardization of the New Protocol (FC/AO), it was compared with the manual method. The results were analyzed according to the recommendations of the National Committee for Clinical Laboratory Standards (NCCLS), now known as Clinical and Laboratory Standards Institute (CLSI), to evaluate the interchangeability of methods in linear regression analysis and paired t test, besides other quality control tests. Conclusion: Based on these results concerning to the correlation between the methods and the tests related to quality control, we can admit that FC/AO for reticulocyte counting shows undeniable advantages when compared to the preexisting manual method...

Introdução: Atualmente, a contagem de reticulócitos representa um desafio para os laboratórios clínicos no Brasil, principalmente os de pequeno e médio porte, nos quais ainda se utiliza o método manual. Este método apresenta algumas limitações, classificando-se como tedioso, demorado e de baixa precisão. Objetivos: O presente estudo desenvolveu e avaliou o desempenho de um novo protocolo laboratorial para contagem de reticulócitos por citometria de fluxo (CF) utilizando acridine orange (AO) como corante, visando padronizar um protocolo preciso, de fácil e rápida execução e custo acessível. Após a padronização do novo protocolo desenvolvido (CF/AO), fez-se a comparação com o método manual. Os resultados foram analisados de acordo com recomendações do National Committee for Clinical Laboratory Standards (NCCLS), atualmente Clinical and Laboratory Standards Institute (CLSI), para avaliar a intercambialidade entre os métodos, por meio da análise de regressão linear e teste t pareado, além de outros testes de controle de qualidade. Conclusão: Diante dos resultados obtidos referentes à correlação entre os métodos e os testes voltados ao controle de qualidade, pode-se admitir que o CF/AO estabelecido para contagem de reticulócitos possui vantagens inegáveis quando comparado com o método manual...

Quantitative detection of target cells using unghosted cells (UGCs) of DxH 800 (Beckman Coulter).

BACKGROUND: In the Retic channel of DxH 800 (Beckman Coulter), the red blood cells (RBCs) resistant to hemoglobin clearing are counted as unghosted cells (UGCs). The aim of this study was to evaluate that the UGC is a surrogate marker for both the detection and counting of target cells. METHODS: In total, 1181 samples including 22 from iron deficiency anemia (IDA) patients, 95 from jaundice, 2 from sickle cell anemia, 3 from thalassemia, 1 cord blood, and 269 from normal controls were analyzed. Slides were prepared from all samples except normal controls and target cells were counted for correlation analysis of target cell counts to UGCs. RESULTS: The normal control samples showed 0.01% (0%-0.01%) UGCs, and the reference range was set at ≤0.02%. The IDA samples showed 0.015% (0.01%-0.03%) UGC count and 0.05% (0%-0.2%) target cell count. The jaundice samples showed 0.98% (0.1%-5.36%) UGC count, and 1.4% (0.1%-7.0%) target cell count. The two sickle cell anemia samples showed 0.41% and 3.74% UGC counts and 0.4% and 11.5% target cell counts. A cord blood sample showed 0.01% UGCs and 0% target cells. The three thalassemia samples showed 0.01%, 1.99%, and 7.82% UGC counts and 0%, 1.4%, and 15.5% target cell counts. The samples showing poikilocytosis other than target cells showed normal UGC count (≤0.02%). The positive predictive value of UGCs was 58.2% (124/213) and the negative predictive value was 96.8% (674/696). The UGC counts were well correlated to the manual target cell counts (r=0.944, p=0.000). CONCLUSIONS: This study demonstrates for the first time in the literature that a hematological parameter obtained automatically every time a reticulocyte counting is performed can be used to both screen for the presence of target cells and reliably quantify them.