Recent advances in laboratory hematology reflected by a decade of CCLM publications.

On the occasion of the 60th anniversary of Clinical Chemistry and Laboratory Medicine (CCLM) we present a review of recent developments in the discipline of laboratory hematology as these are reflected by papers published in CCLM in the period 2012-2022. Since data on CCLM publications from 1963 to 2012 are also available, we were able to make a comparison between the two periods. This interestingly revealed that the share of laboratory hematology papers has steadily increased and reached now 16% of all papers published in CCLM. It also became evident that blood coagulation and fibrinolysis, erythrocytes, platelets and instrument and method evaluation constituted the 'hottest' topics with regard to number of publications. Some traditional, characteristic CCLM categories like reference intervals, standardization and harmonization, were more stable and probably will remain so in the future. With the advent of important newer topics, like new coagulation assays and drugs and cell population data generated by hematology analyzers, laboratory hematology is anticipated to remain a significant discipline in CCLM publications.

Role of RDW in mathematical formulas aiding the differential diagnosis of microcytic anemia.

Many mathematical formulas containing simple red blood cell parameters have been proposed for differentiating between iron deficiency and thalassemia in patients with microcytic anemia. Approximately half of these formulas do include red cell distribution width (RDW), along with other red cell parameters. In the present study we investigated the role of RDW, expressed in relative or in absolute units in relation with the formulas' discriminant performance. We used a database containing over 2200 subjects with microcytic anemia, for whom a final diagnosis (iron-deficiency anemia, thalassemia, both or other) was available. Performance of the discriminant formulas was assessed by Receiver Operator Curve analysis. Substitution of relative by absolute RDW resulted in statistically significant performance increase (area under the ROC curve) in 16 out of 23 formulas, predominantly due to increased specificity. Relevant performance deterioration was seen in only three formulas that had low initial performance already with the original relative RDW. For optimal differential diagnostic performance, an RDW-based formula for distinguishing thalassemia from iron-deficiency anemia in microcytic anemia should contain 'absolute' instead of relative RDW.

Verification of 20 Mathematical Formulas for Discriminating Between Iron Deficiency Anemia and Thalassemia Trait in Microcytic Anemia.

BACKGROUND: Currently, more than 45 mathematical formulas based on simple red blood cell (RBC) parameters have been proposed for differentiating between iron deficiency and thalassemia in microcytic anemia, of which 20 are relatively new and have not been thoroughly independently verified. The study goal was to verify these 20 new formulas and to identify which RBC parameters have a decisive impact on the performance of those formulas. METHODS: A database containing laboratory and diagnostic data from 2788 subject individuals with microcytic anemia was used for assessing performance by receiver operating characteristic (ROC) analysis. RESULTS: The new Index26 had excellent performance, equivalent to the Green and King, Jayabose, and Janel formulas previously identified in the literature. The discriminant power of nearly all newer formulas was lower in our study than that claimed by the original authors. We discovered that a well-performing formula requires mean cell volume (MCV), RBC distribution width (RDW), and RBC measurements, whereas hemoglobin measurements appeared not to be essential. CONCLUSIONS: Only the new Index26 performed at a level comparable to the very strongest established formulas. All other new formulas had lower performance than was claimed in the original publications, underscoring that independent verification of new formulas is indispensable.

Basophil counting in hematology analyzers: time to discontinue?

Basophils (basophilic granulocytes) are the least abundant cells in blood. Nowadays, basophils are included in the complete blood count performed by hematology analyzers and therefore reported in practically all patients in whom hematologic investigations are requested. However, hematology analyzers are not reliable enough to report clinically useful results. This is due to a combination of very high analytical imprecision and poor specificity, because the chemical and physical methods used for basophil counting in hematology analyzers are ill-defined and thus basophils are not well recognized by the analyzers. As a result, false basophil counts are quite common. In view of increasing analytical performance demands, hematology laboratories should stop reporting basophil counts produced by hematology analyzers. Suggestions for alternative pathways are presented for those situations where basophils are of clinical relevance.

Multicenter performance evaluation of the Abbott Alinity hq hematology analyzer.

Background Alinity hq (Abbott) is a new high-throughput hematology analyzer that exclusively employs optical principles for detecting and enumerating blood cells. It reports 29 parameters, including a six-part white blood cell (WBC) differential. The aim of this multicenter study was to evaluate the analytical and clinical performance of the Alinity hq. Methods Complete blood count (CBC) results and morphological flagging were compared to that of CELL-DYN Sapphire (Abbott) and 2 × 200-cell manual differential results, on 1473 whole-blood samples from a well-defined patient population from three different clinical laboratories in the Netherlands. In addition, within-run and within-laboratory precision, linearity, limit of quantitation, carryover and sample stability were assessed. External quality assessment samples were also evaluated. Results Data analysis demonstrated strong concordance of Alinity hq results with those of CELL-DYN Sapphire for all CBC parameters, except for basophil granulocytes. Alinity hq WBC differential showed high level of agreement with manual differential results and exhibited a better agreement with manual basophil results than CELL-DYN Sapphire. The sensitivity of the Alinity hq Blast flag was 57.6%, equal to the 57.6% sensitivity of the CELL-DYN Sapphire's Blast Alert. When considering samples with ≥5% blasts, the sensitivity of the Alinity hq Blast flag was 70.0%. Analytical performance of Alinity hq was shown to be consistent with state-of-the-art (SOTA) performance characteristics. Conclusions Alinity hq CBC measurands demonstrated good overall agreement with results obtained with CELL-DYN Sapphire, as well as manual WBC differential. The analytical and clinical performance characteristics of Alinity hq make it well suited for clinical laboratories.

Assessment of iron-restricted erythropoiesis in chronic renal disease: evaluation of Abbott CELL-DYN Sapphire mean reticulocyte hemoglobin content (MCHr).

We studied the performance of mean reticulocyte hemoglobin content (MCHr), measured on Abbott CELL-DYN Sapphire analyzer for the detection of functional iron deficiency. Patients with anemia and with renal disease were prospectively selected from the outpatient population of our hospital, 512 subjects were studied. Diagnoses and other medical data were retrieved from the hospital information system. MCHr was measured using a CELL-DYN Sapphire hematology analyzer (Abbott Diagnostics). Standard laboratory and statistical tests were used. Receiver operating characteristic (ROC) analysis was used to establish the diagnostic performance of MCHr for detecting iron-restricted erythropoiesis, with transferrin saturation <20% as the gold standard. Patients in the iron deficiency anemia group all had a state of iron depletion and iron-restricted erythropoiesis (median MCHr 25.4 pg). Patients with anemia of chronic disease showed also low MCHr, median 27.6 pg, but not statistically different from the iron deficient group (p = .0585). Renal patients with iron restriction (n = 66) had significantly lower MCHr (p < .0001) than those receiving adequate iron supply (n = 100): median MCHr were 27.9 and 32.5 pg, respectively. ROC analysis gave sensitivity 84.4% and specificity 80.1% with area under curve 0.863 (95% CI 0.823-0.902) at an MCHr cut-off 30.0 pg. MCHr on CELL-DYN Sapphire has equivalent clinical performance for detecting absolute or functional iron deficiency in patients with chronic kidney disease as previously published for another type of analyzer.

Comparative evaluation of platelet counts in two hematology analyzers and potential effects on prophylactic platelet transfusion decisions.

BACKGROUND: Decisions on prophylactic platelet (PLT) transfusions are generally based on the recipient's PLT count, but few clinicians are aware of precision and accuracy of the PLT counting methods used by the clinical laboratory. Each PLT counting technology has its specific inaccuracy, especially in thrombocytopenic samples and therefore may impact decisions on PLT transfusions. STUDY DESIGN AND METHODS: Five routine PLT counting methods available in two hematology analyzers (Sysmex XN-2000 and Abbott CELL-DYN Sapphire) were investigated (impedance and optical on both analyzers and fluorescent on XN-2000), using the CD61 immunologic PLT method as a reference. The impact of counting inaccuracy on imaginary transfusion decisions was examined at various common PLT thresholds. RESULTS: In total 341 samples were analyzed, 178 of which had PLT counts of less than 35 × 109 /L. Despite excellent overall correlation with the reference method (r > 0.99), thrombocytopenic samples showed only modest correlation for impedance and XN-2000 optical methods. Sapphire optical and XN-2000 fluorescent methods correlated very well with the reference, albeit with bias in the very low range. We noticed potential risk of undertransfusion (ranging from 2% to 90%), depending on the threshold used. The risk of overtransfusion was small (<10%). CONCLUSIONS: The XN-2000 fluorescent PLT counting method showed excellent correlation with the CD61 reference count, closely followed by the CELL-DYN Sapphire optical method. XN-2000 impedance and optical and Sapphire impedance methods are not accurate enough for basing transfusion decisions on. Only XN-2000 fluorescent, Sapphire optical, and CD61 methods are sufficiently accurate for making appropriate clinical decisions in patients with severe thrombocytopenia.

Reticulocyte hemoglobin content (MCHr) in the assessment of iron deficient erythropoiesis in inflammatory bowel disease.

BACKGROUND: In conditions associated with inflammation, biochemical parameters alone could be inadequate for assessing iron status. We investigated the potential utility of mean reticulocyte hemoglobin content (MCHr) in the assessment of the erythropoiesis status in inflammatory bowel disease (IBD). METHODS: We recruited 124 anemic outpatients with IBD. Serum iron, transferrin and ferritin were tested. Complete blood counts were performed on a CELL-DYN Sapphire analyzer (Abbott Diagnostics). Differences among groups were assessed using analysis of variance, considering P < 0.05 to be significant. Receiver operating characteristic analysis was used to assess the diagnostic performance of MCHr for detecting iron deficient erythropoiesis. The reference used as an indicator of insufficient iron availability was transferrin saturation <20%. RESULTS: Overall, 47.6% of the patients had iron deficiency anemia (IDA) and 31.5% anemia of chronic disease (ACD), while the others (20.9%) had mixed anemia. Patients with ACD or mixed anemia showed functional iron deficiency: normal or high ferritin and low MCHr. The area under curve was 0.858 (95% CI 0.742-0.942), considering a cut off 30.3 pg, the sensitivity was 82.2%, specificity 83.3%. CONCLUSIONS: MCHr provides information on iron availability in IBD patients. It is a reliable test to assess iron supply for erythropoiesis.

Critical appraisal of discriminant formulas for distinguishing thalassemia from iron deficiency in patients with microcytic anemia.

BACKGROUND: Many discriminant formulas have been reported for distinguishing thalassemia trait from iron deficiency in patients with microcytic anemia. Independent verification of several discriminant formulas is deficient or even lacking. Therefore, we have retrospectively investigated discriminant formulas in a large, well-characterized patient population. METHODS: The investigational population consisted of 2664 patients with microcytic anemia: 1259 had iron deficiency, 1196 'pure' thalassemia trait (877 ß- and 319 α-thalassemia), 150 had thalassemia trait with concomitant iron deficiency or anemia of chronic disease, and 36 had other diseases. We investigated 25 discriminant formulas that only use hematologic parameters available on all analyzers; formulas with more advanced parameters were disregarded. The diagnostic performance was investigated using ROC analysis. RESULTS: The three best performing formulas were the Jayabose (RDW index), Janel (11T), and Green and King formulas. The differences between them were not statistically significant (p>0.333), but each of them had significantly higher area under the ROC curve than any other formula. The Jayabose and Green and King formulas had the highest sensitivities: 0.917 both. The highest specificity, 0.925, was found for the Janel formula, which is a composite score of 11 other formulas. All investigated formulas performed significantly better in distinguishing ß- than α-thalassemia from iron deficiency. CONCLUSIONS: In our patient population, the Jayabose RDW index, the Green and King formula and the Janel 11T score are superior to all other formulas examined for distinguishing between thalassemia trait and iron deficiency anemia. We confirmed that all formulas perform much better in ß- than in α-thalassemia carriers and also that they incorrectly classify approximately 30% of thalassemia carriers with concomitant other anemia as not having thalassemia. The diagnostic performance of even the best formulas is not high enough for making a final thalassemia diagnosis, but in countries with limited resources, they can be helpful in identifying those patients who need further examinations for genetic anemia.

Reticulocyte hemoglobin content (MCHr) in the detection of iron deficiency.

BACKGROUND: Blood hemoglobin (Hb) concentration within the reference interval does not exclude iron deficiency (ID): individuals with normal stores lose iron during a long period before their Hb falls below of the level that is defined as anemia. The process entails a decrease of storage iron, shown by serum ferritin below reference range, followed by iron depletion, eventually leading to iron restricted erythropoiesis; consequence of an imbalance between erythropoietic iron requirements and too low supply is a reduction of Hb synthesis in reticulocytes. OBJECTIVE: We study the potential utility of mean reticulocyte hemoglobin content (MCHr), reported by CELL-DYN Sapphire (Abbott Diagnostics) analyzer, in the detection of ID in non-anemic adults. METHODS: 207 patients with Hb within the reference range were enrolled. ID was defined as Hb>120g/L (women), >130g/L (men) and serum ferritin <30µg/L. Student's t-test was applied to detect deviations between groups, statistical significance P<0.05. The performance of MCHr in detecting ID was evaluated applying Receiver Operating Characteristic (ROC) curve analysis. Kappa test was applied to verify concordance between ferritin and MCHr. RESULTS: 68 patients (33%) suffered ID, median MCHr in this group was 26.9 pg, statistically different from the normal group, MCHr 30.9pg (P<0.0001). ROC ANALYSIS (GOLD STANDARD FERRITIN <30µG/L): Area under curve AUC 0.851 (95% CI 0.770-0.912) at cut off 30.0 pg, with sensitivity 84.1% and specificity 71.1%. Kappa 0.667 (95% CI 0.527-0.858). CONCLUSION: Due to their short lifespan reticulocytes and derived parameters reflect current erythropoiesis status, before Hb and erythrocyte indices drop. MCHr had the best AUC and diagnostic value compared to erythrocyte indices. MCHr is a reliable test for the investigation of ID and could improve the detection of iron deficient adults.