RETICULOCYTE COUNT METHODS.
Explore the source record for details and available documents.
Erythrocyte Count↗
SEARCH · Search PubMed
Results for “Reticulocyte Count”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Evaluation of a semi-automated reticulocyte counting method using the Coulter STKS-2A blood cell counter.
Reticulocyte counting was assessed on the Coulter STKS-2A automated blood cell counter. Using a two step procedure, blood samples were first incubated with the supravital stain new methylene blue. An acidic reagent was then added to clear the haemoglobin and any stained RNA was preserved within the cell. The cells were then analysed by measurement of volume, conductivity and light scatter (VCS). The results of 123 samples analysed on the STKS-2A were compared with those from a Toa Sysmex R-1000 reticulocyte counter. One hundred and seven samples gave no review flags and reticulocyte counts ranging from 0.5% to 22.8%, resulting in a correlation coefficient of 0.93 for the methods. Between run imprecision studies gave CVs ranging from 5.3% for a reticulocyte count of 8.7% to a CV of 16.3% for a 0.34% count. Stability studies showed insignificant changes over 72 h storage. These findings confirm that VCS technology can be adapted to provide precise and accurate routine reticulocyte analysis.
Automation↗
The reticulocyte count and its subfractions in smoking and non-smoking pregnant women.
UNLABELLED: Our objective was to compare the reticulocyte count and its subfractions in smoking and non-smoking women at different stages of normal pregnancy. STUDY DESIGN: In 247 non-smoking and 123 smoking healthy pregnant women the reticulocyte count and its subfractions were compared at four different stages of pregnancy: 0-10, 11-20, 21-30 and 31-40 weeks. Exclusion criteria were a diastolic blood pressure > or = 90 mmHg, an endocrine disease or a coagulation disorder. Women in the smokers group smoked more than 4 cigarettes a day. Non-smokers were defined as women reporting no smoking at all. Blood samples were run on the Sysmex R-3000 reticulocyte counter. RESULTS: The absolute reticulocyte count was lower in the smoking group throughout pregnancy, but this was only significant in the last ten weeks of gestation (71.9 x 10(9)/l versus 78.8 x 10(9)/l). There was no difference between the low fluorescence, the medium fluorescence and the high fluorescence proportions in the non-smoking and the smoking group. Both groups behaved similarly during pregnancy; there was a decrease of mature reticulocytes and a significant increase of more immature reticulocytes. CONCLUSION: These data show a moderate measurable effect of cigarette smoking on the reticulocyte count and the absence of an effect on the reticulocyte subsets.
Adult↗
[Reticulocytosis and reticulocyte count].
Explore the source record for details and available documents.
Erythrocyte Count↗
THE RETICULOCYTE COUNT: LABORATORY PROCEDURES FOR THE OFFICE.
Explore the source record for details and available documents.
Blood Cell Count↗
On the diagnosis of erythrocyte enzyme defects in the presence of high reticulocyte counts.
The separation of red blood cells into reticulocytes and young and old erythrocytes enables investigations of fractions with different contents of reticulocytes. Activities of hexokinase, glucose phosphate isomerase, phosphofructokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase showed a linear relationship to reticulocyte counts. The dependence of these enzyme activities on the age of the red blood cells exhibited a strong decline from the reticulocyte to the young erythrocyte stage followed by only little further loss of activity, thus leading to a biphasic decay of enzyme activities. By linear regression analysis enzyme activities in erythrocytes (AE) and reticulocytes (AR) could be evaluated. The activity of a given enzyme in the reticulocyte exceeded that of the erythrocyte; the quotient AR/AE represents the decline of enzyme activity from the reticulocyte to the erythrocyte stage. This value AR/AE is 16.7 for pyruvate kinase and 9.4 for hexokinase and thus considerably higher than that for the other enzymes investigated (glucose phosphate isomerase: 2.9, phosphofructokinase: 4.3, glucose-6-phosphate dehydrogenase: 4.5). In patients suffering from erythrocyte enzymopathies, the AR/AE for pyruvate kinase was 16.2 and thus almost identical to the normal enzyme. Calibration curves where the enzyme activity is plotted versus the fraction of reticulocytes enable the determination of normal activity of a given erythrocyte enzyme depending on the content of reticulocytes in red blood cell suspensions. Thus an unambiguous diagnosis of enzyme defects irrespective of reticulocyte counts becomes possible.
Adult↗
Correction of anaemia following renal transplantation: serial changes in serum immunoreactive erythropoietin, absolute reticulocyte count and red-cell creatine levels.
Improvement of erythropoiesis following successful human renal transplantation in eight patients was monitored by sequential measurements of haemoglobin, red-cell creatine, absolute reticulocyte count and estimates of serum immunoreactive erythropoietin (siEp). SiEp increased in five patients after transplant, in three cases almost immediately after a return to normal of plasma creatinine. The increase in siEp was followed by a rise in the absolute reticulocyte count and red-cell creatine and finally by an increase in the haemoglobin level. As the haemoglobin approached normal levels a decline in the absolute reticulocyte count preceded a fall in siEp levels. Red-cell creatine also fell, though more gradually than the reticulocyte count. Acute graft rejection (in two patients) was associated with a fall in siEp. Chronic rejection (in one patient) was associated with persistent increases in siEp, reticulocyte count and red-cell creatine; this patient subsequently developed erythrocytosis.
Adult↗
[Diagnosis of pyruvate kinase deficiency in the presence of an elevated reticulocyte count].
HISTORY AND CLINICAL FINDINGS: Three members of one family (mother, now aged 44 years; daughter, now aged 23 years, and son, now aged 19 years) have had chronic haemolytic anaemia since their infancy. All three have had several blood transfusions a year because of haemoglobin (Hb) concentrations as low as 5 g/dl due to intermittent increases in haemolysis. Despite an unclear diagnosis all three had splenectomies: their spleens had been enlarged to about 5-7 cm below the rib margin. After splenectomy their haemoglobin concentration rose to 9-12 g/dl and the previously raised reticulocyte count of 150-250/1000 rose further to 400-700/1000. None of the patients had symptoms other than a slight decrease in exercise tolerance. They were admitted to hospital for further evaluation. Physical examination was unremarkable except for slight jaundice and well healed splenectomy scar. TESTS: All three patients had normochromic haemolytic anaemia (Hb 10-12 g/dl), bilirubin 2-3 mg/dl, lactate dehydrogenase activity 400-600 U/l). The reticulocyte count was raised to 420-690/1000. In all of them pyruvate kinase (PK) activity was normal or slightly increased if related to Hb concentration. Reticulocytes from healthy persons were isolated by density-gradient centrifugation so that samples could be prepared with different numbers of reticulocytes: PK activity was found to be dependent on the sample's reticulocyte count. In the three patients PK deficiency could, therefore, only be diagnosed by taking into account the raised reticulocyte count. CONCLUSION: As reticulocytes have a higher PK activity than erythrocytes the reticulocyte count must be taken into account when assessing the significance of a given value of this enzyme's activity.
Adult↗
Relation between reticulocyte count and characteristics of erythrocyte 5'-nucleotidase in dogs, cats, cattle and humans.
To examine substrate specificity and susceptibility to lead, erythrocyte 5'-nucleotidase was measured in dogs, cats, cattle and humans, and its relationship to the reticulocyte count in these species was determined. The reticulocyte count in dogs was similar to that in humans, but the count in cats was higher than that in humans. Reticulocytes were not observed in cattle. The activities of canine erythrocyte 5'-nucleotidase measured using cytidine and uridine 5'-monophosphates, which are preferentially catalyzed by one of the human pyrimidine 5'-nucleotidase isozymes (P5N-I), were similar to those of the human enzyme. The canine enzyme preferentially catalyzed thymidine 3'-monophosphate, which is catalyzed only by human P5N-II, more strongly than the human enzyme. This suggests that canine erythrocytes have two isozymes similar to human P5N-I and P5N-II, and a higher P5N-II-like activity than human erythrocytes. Feline erythrocytes had the highest level of P5N-I-like activity among the species examined, and the bovine enzymic activities including those of P5N-I and II were the lowest among these species. According to these observations, the reticulocyte count was approximately proportional to the P5N-I-like activity in these species. Therefore, the P5N-I-like activity may be involved in the morphological maturation of mammalian erythrocytes. The canine and feline erythrocytes had markedly high activity and preferentially catalyzed purine 5'-monophosphate suggesting the presence of a purine-specific 5'-nucleotidase as in human erythrocytes. In addition, the canine and feline P5N-I-like activity showed less susceptibility to lead than the human P5N-I. This may be a reason why there are few case reports of lead-induced anemia in dogs and cats.
5'-Nucleotidase↗
Reticulocyte counting by flow cytometry. A comparison with manual methods.
The reticulocyte count (RC) is a key diagnostic test in the evaluation, classification, and response to therapy of anemia. The RC, as determined by manual methods, has a frustrating inherent imprecision owing to its binomial counting statistics (i.e., low counts/low precision) and inaccuracy because of inter- and intraobserver variability as to what indeed is a reticulocyte. Fluorescent activated cytometric (FACS) analysis of reticulocytes by thiazole orange (TO) is a rapid, relatively simple, and precise method for counting reticulocytes. The automated method counts 10,000 cells or more vs. 1,000 cells counted by the manual method. Although inherently more precise, the FACS method may be inaccurate owing to the presence of Howell-Jolly bodies, nucleated red blood cells (RBCs), sickled cells, or giant platelets. The RC by FACS is well correlated with the manual method and the reference ranges are similar. A new parameter by FACS, the reticulocyte maturation index (RMI), provides an independent measurement of reticulocyte RNA content. Although the RMI does not correlate with RC either by FACS or manual methods, it does provide an independent parameter of erythropoietic activity and may be useful in predicting bone marrow engraftment or further subclassifying anemias. Determination by FACS of the RC offers significant advantages over manual methods in monitoring a patients erythropoietic response. However, one must be cognizant of potential pitfalls in the method.
Adult↗
Clinical significance of immature reticulocyte fraction determined by automated reticulocyte counting.
The Sysmex R-3000 (TOA Medical Electronics, Kobe, Japan) evaluates maturation of reticulocytes by quantitating the fraction of reticulocytes within low-, middle-, and high-fluorescence intensity regions. We defined the immature reticulocyte fraction (IRF) as the sum of the fraction of high-fluorescence intensity regions plus the fraction of middle-fluorescence intensity regions. Then, we studied the clinical significance of IRF in the evaluation of anemia by comparing the IRF with the absolute reticulocyte count (ARC) and with the reticulocyte production index (RPI) and by reviewing pertinent clinical information about the patients. In the study, 132 specimens from 102 patients undergoing evaluation of anemia were analyzed. By using simple regression analysis, our results showed that the IRF has a weak but significantly positive correlation with ARC and with RPI, indicating that IRF is an additional useful parameter to evaluate the erythropoietic activity in anemia. Interpretation by integrating IRF and reticulocyte enumeration (ARC and RPI) provided useful information for further subclassification of anemia. Increased IRF (IRF > or = 0.23) and increased ARC generally indicated an adequate erythroid response to anemia. All but three specimens with an IRF less than 0.23 showed an RPI of 2 or less. These specimens were from patients with underlying diseases known to lead to decreased erythropoietic activity, predominantly chronic renal insufficiency. Specimens with a subnormal or normal ARC (with a corresponding RPI < or = 2) but with an IRF of more than 0.23 were from patients with various underlying conditions, including acute infection, iron deficiency anemia, human immunodeficiency virus infection, sickle disease with crisis, pregnancy, and myelodysplastic syndrome. Our results indicate that an IRF of 0.23 or less in patients with anemia reflects bone marrow that is nonresponsive or underresponsive to the anemia. Patients with an increased IRF (IRF > or = 0.23) may require further examination to clarify the cause of the anemia.
Adult↗
Proficiency testing in reticulocyte counting.
The Laboratory Proficiency Testing Program tests and evaluates proficiency of clinical laboratories in Ontario, Canada. The programme began in 1974; testing of reticulocyte counts was added in 1982. From the beginning, the goal of the programme has been to ensure that the quality of practice in Ontario laboratories facilitates good quality patient care. Testing of indirect counting methods for reticulocytes is accomplished by the distribution of stained blood films. Performance is expressed in terms of accuracy and precision. Proficiency is assessed by comparing submitted results to an all-methods' mean and result reliability by observing the coefficient of variation (CV) of the cohort. The quality of the results vary neither with the manual counting system used nor the type of laboratory. The CV commonly ranges from 25 to 30%, and this lack of accuracy appears to be inherent in the technology of manual reticulocyte counting. We conclude that manual reticulocyte counting is technologically obsolete but may be of clinical value if used in a qualitative fashion. It should probably be replaced by an automated method.
Analysis of Variance↗
Diagnostic value of anemia, red blood cell morphology, and reticulocyte count for sickle cell disease.
STUDY OBJECTIVE: To determine the diagnostic value of anemia, RBC morphology, and reticulocyte count for differentiating patients with sickle cell trait from those with sickle cell disease, who have acute medical or surgical conditions and a positive sickle cell screen. DESIGN: Retrospective chart review. SETTING: A midwest urban children's hospital with 220 beds and 36,000 emergency department visits per year. PARTICIPANTS: One hundred six patients with sickle cell trait and 152 patients with sickle cell hemoglobinopathies. RESULTS: Anemia was observed significantly more often in patients with sickle cell disease compared with sickle cell trait (P less than .001) at all ages 3 months and older. However, anemia alone as a diagnostic test lacked high sensitivity and specificity in children less than 4 years old. Sensitivity approached 100% with the presence of anemia, abnormal RBC morphology, or reticulocyte count of more than 2%. CONCLUSION: Absence of anemia alone does not exclude the diagnosis of sickle cell disease in children less than 4 years old. To differentiate trait from sickle cell disease, we recommend determination of not only hemoglobin adjusted for age but also of RBC morphology and reticulocyte count on all children presenting with acute medical and surgical conditions and a positive sickle cell screen.
Adolescent↗
Comparison of red cell creatine level and reticulocyte count in appraising the severity of hemolytic processes.
In seeking a sensitive indicator for quantitative assessment of hemolytic disease, we found a close dependence of red cell creatine level on cell age. Studies in 21 patients with steady-state hemolysis showed high correlation (r=0.89, p less than 0.001) between reticulocyte counts and red cell creatine levels. Excluding elevation of the creatine level as a variable epiphenomenon of increased erythropoietic activity, density separation of normal red cells revealed distinctly higher creatine levels in younger cells. The reticulocyte counts and creatine levels as quantitative predictors of hemolytic processes were compared: in severe hemolytic anemias (T50Cr less than 11 days), erythrocyte survival (T50Cr) correlated well with creatine levels (r = -0.86, p less than 0.01) and, to a lesser degree, with reticulocyte counts (r = -0.72, p less than 0.05). In milder disease (T50Cr greater than 11 days), however, no correlation existed between reticulocyte counts and T50Cr, whereas the creating levels correlated closely with T50Cr (r = -0.84, p less than 0.001). Thus, on the basis of our regression equations, useful estimation of red cell survival may be obtained from single measurements of erythrocyte creatine.
Adolescent↗
Reticulocyte counting.
Explore the source record for details and available documents.
Erythrocyte Count↗
Glycaemic control and reticulocyte count in diabetic patients.
Correlation coefficients between glycosylated haemoglobin, mean fasting glycaemia, and reticulocyte count have been assessed in 61 diabetic patients. When excluding those with overt anaemia and with serum iron below 12.5 mumol/l, the correlations became significant. Thus, reticulocyte count may be a useful indicator of glycaemic control (paralleling HbgAIc), provided anaemia and low serum iron are excluded.
Adult↗
Evaluation of automated reticulocyte counts and their reliability in the presence of Howell-Jolly bodies.
An automated reticulocyte procedure using a flow cytometer and the fluorescent dye thiazole orange was evaluated for clinical use. The mean reticulocyte count on 118 hematologically healthy adults was 1.56% (standard deviation [SD] 0.54), with virtually no difference in percentage between women and men. The mean absolute values were 68.4 x 10(9)/L (SD 24.6) and 75.7 x 10(9)/L (SD 27.2), respectively. When compared with the standard microscopic technique, the automated method showed excellent correlation (r = 0.98) and greatly improved precision (coefficient of variation [CV] 4.1%) over the manual method (CV 22.8%). Preanalytic storage of blood samples at 4 degrees C for up to 48 hours did not significantly affect results, nor did varying the incubation time of diluted samples from 1/2 to 2 hours. In a group of patients with appreciable numbers of Howell-Jolly bodies, automated reticulocyte counts were spuriously elevated. The difference between the manual and automated counts on these patients approximated the percentage of Howell-Jolly bodies observed on their Wright-Giemsa stained blood smears.
Adolescent↗
[Predictive significance of reticulocyte count (interpretative methodologic approach)].
This study concerns the comparison of two methodologies for reticulocyte count on two groups of 100 subjects. The evaluation of the results achieved with the two colorants (brilliant cresyl blue and pre-colored glasses with crystal acetate violet and methylene blue) suggests the application of more reliable parameters (reticulocyte index, reticulocyte production index) for the interpretation of reticulocyte counting. It seems desirable to correct the absolute reticulocyte number with the degree of anemia of the patient and to calculate the medullary production index to identify the effective reticulocytosis.
Anemia↗