Comparing automated vs manual leukocyte differential counts for quantifying the 'left shift' in the blood of neonates

Significant Variability in the Identification and Reporting of Band Neutrophils by Participants Enrolled in the College of American Pathologists Proficiency Testing Program: Time for a Change

CONTEXT.—

Increased band neutrophils in blood smear differential counts ("bandemia") are entrenched in medicine as a flag for sepsis. However, laboratory hematology experts have long advocated for discontinuation of reporting bands separately from segmented neutrophils because of poor sensitivity and specificity, poor interobserver agreement, and availability of alternative biomarkers for sepsis.

OBJECTIVE.—

To describe band neutrophil reporting practices and reproducibility of band classification among laboratories participating in the College of American Pathologists (CAP) proficiency testing (PT) program.

DESIGN.—

A survey questionnaire was distributed to hematology PT participants. A subsequent morphologic challenge included 12 preselected cell identifications of segmented neutrophils, bands, and metamyelocytes, and a 100-cell manual differential count of a digitally scanned blood smear.

RESULTS.—

Among laboratories that reported manual differentials, most respondents reported bands (4554 of 5268; 86.4%). Only 3222 of 4412 respondents (73.0%) provided band reference ranges. Though participants classified "easy" band neutrophils well (78.0%-98.3%), categorization of cell identifications for "moderate" and "difficult" bands was poor (3.1%-39.0% of laboratories), with classification instead as segmented neutrophils. This pattern was seen regardless of laboratory demographic characteristics. Marked variability in band counts was observed on the 100-cell differential count for both CAP PT participants and CAP Hematology and Clinical Microscopy Committee (HCMC) members (coefficients of variation, 55.8% and 32.9%, respectively). Variability was significantly improved when segmented and band neutrophils were grouped together (coefficients of variation, 6.2% and 5.0%, respectively).

CONCLUSIONS.—

Most CAP PT-participating laboratories report band counts, many without reference ranges. The survey confirms significant interlaboratory variability of band enumeration when bands are separately identified from segmented neutrophils. This study reaffirms the CAP Hematology and Clinical Microscopy Committee's strong recommendation to group segmented and band neutrophils together in manual differential counts.

Implications of an Elevated Nucleated Red Blood Cell Count in Neonates with Moderate to Severe Hypoxic-Ischemic Encephalopathy

OBJECTIVES

To investigate associations between nucleated red blood cell (NRBC) count in neonates with hypoxic-ischemic encephalopathy (HIE), acute perinatal sentinel events, and neurodevelopmental outcomes and to examine the mechanism(s) causing elevated counts.

STUDY DESIGN

We included newborn infants with HIE treated with therapeutic hypothermia with ≥3 NRBC counts during their neonatal intensive care unit hospitalization and neurodevelopmental evaluations at a mean of 24 ± 6 months.

RESULTS

Ninety-five of 152 infants who met our study criteria (63%) had a normal NRBC count after birth, defined as ≤95th percentile of the upper reference interval, and the other 57 (37%) had an elevated count. Documented sentinel events during labor resulting in emergency delivery (eg, acute abruption) (n = 79) were associated with a normal NRBC count (OR, 257; 95% CI, 33-1988). Of the 152 infants evaluated, 134 (88%) survived to discharge. The odds of surviving were 3-fold greater (OR, 3.0; 95% CI, 1.1-8.3) when the first NRBC count was normal than when it was elevated. Normal counts were moderately predictive of infants without neurodevelopmental impairment at a 2-year evaluation (P < .001). NRBC half-life was longer in infants with an elevated NRBC count compared with those with a normal count (60 hours vs 39 hours; P < .01).

CONCLUSIONS

In infants with HIE, a normal NRBC count after birth was associated with acute intrapartum events necessitating emergent delivery. Normal counts were modestly predictive of a better prognosis. We speculate that the elevated NRBC counts at birth resulted from hypoxia that occurred earlier or chronically. Impaired clearance of NRBCs from the blood might be one mechanistic explanation for the high counts.

Evaluation of Immature Granulocyte Count as the Earliest Biomarker for Sepsis

Background

Diagnosing sepsis early is important for its successful management. Various biomarkers are being used currently, but mostly they are either expensive or not readily available. This study aims to evaluate usefulness of automated immature granulocyte count (IG#) and immature granulocyte percentage (IG%) as early diagnostic markers of sepsis and compares it to other established predictive markers.

Patients and methods

In this prospective observational study, 137 eligible, critically ill, nonseptic intensive care unit patients were analyzed for automated IG#, IG%, serum procalcitonin (PCT), and blood lactate (Lac), daily for 7 days after recruitment. Patients were followed for the development of sepsis, defined by the new Sepsis-3 criteria. The study was divided into four time periods of 24 hours each with respect to the day of developing organ dysfunction. Using area under receiver operator characteristic and diagnostic odds ratio (DOR) methods, the best biomarker for the prediction of sepsis in each time period was calculated.

Results

IG# and IG% were the earliest biomarkers to have a significant discriminating value with area under the curve of 0.81 and 0.82, respectively, as early as 24 hours before clinical sepsis is diagnosed by Sepsis-3 criteria. Both IG# and IG% have a high DOR of 34.91 and 18.11, respectively, when compared to others like PCT and Lac having a DOR of 27.06 and 4.78, respectively.

Conclusion

IG# and IG% are easily available, rapid, and inexpensive tools to differentiate between septic and nonseptic patients with high specificity and sensitivity. It is the earliest biomarker to show a significant rise in patients developing sepsis.

How to cite this article

Bhansaly P, Mehta S, Sharma N, Gupta E, Mehta S, Gupta S. Evaluation of Immature Granulocyte Count as the Earliest Biomarker for Sepsis. Indian J Crit Care Med 2022;26(2):216–223.

Reconciling markedly discordant values of serum ferritin versus reticulocyte hemoglobin content

OBJECTIVE

To determine why serum ferritin and reticulocyte hemoglobin (RET-He), drawn to assess neonatal iron sufficiency, sometimes have markedly discordant results.

STUDY DESIGN

Retrospective records review of five NICUs over 28 months, identifying all patients with a ferritin and RET-He within 48 h. We examined records of all who had marked discordance (one value >95th % reference interval, the other <5th %).

RESULTS

Of 190 paired ferritin and RET-He measurements, 16 (8%) were markedly discordant. Fifteen of the 16 discordant samples involved a high ferritin and a low RET-He. In these, low MCV and high %Micro-R, and low MCH and high %HYPO-He were present. In total, 8 of the 15 had laboratory or clinical evidence of an inflammatory process and five had suspicion of infection documented.

CONCLUSIONS

When ferritin and RET-He were discordant, erythrocyte microcytosis and hypochromasia suggested that the RET-He gave the more accurate interpretation; that iron deficiency was likely present.

Defining Normal Healthy Term Newborn Automated Hematologic Reference Intervals at 24 Hours of Life

CONTEXT.—

Automated analyzers have advanced the field of clinical hematology, mandating updated complete blood count (CBC) reference intervals (RIs) to be clinically useful. Contemporary newborn CBC RI publications are mostly retrospective, which some authors have cited as one of their cardinal limitations and recommended future prospective studies.

OBJECTIVE.—

To prospectively establish accurate hematologic RIs for normal healthy term newborns at 24 hours of life given the limitations of the current medical literature.

DESIGN.—

This prospective study was conducted at an academic tertiary care center, and hematology samples were collected from 120 participants deemed to be normal healthy term newborns. Distributions were assessed for normality and tested for outliers. Reference intervals were values between the 2.5th percentile and 97.5th percentile.

RESULTS.—

The novel RIs obtained for this study population are as follows: absolute immature granulocyte count, 80/μL to 1700/μL; immature granulocyte percentage, 0.6% to 6.1%; reticulocyte hemoglobin equivalent, 31.7 to 38.4 pg; immature reticulocyte fraction, 35.9% to 52.8%; immature platelet count, 4.73 × 103/μL to 19.72 × 103/μL; and immature platelet fraction, 1.7% to 9.8%.

CONCLUSIONS.—

This prospective study has defined hematologic RIs for this newborn population, including new advanced clinical parameters from the Sysmex XN-1000 Automated Hematology Analyzer. These RIs are proposed as the new standard and can serve as a strong foundation for continued research to further explore their value in diagnosing and managing morbidities such as sepsis, anemia, and thrombocytopenia.

Current Variation in Joint Aspiration Practice for the Evaluation of Pediatric Septic Arthritis

Pediatric septic arthritis (SA) is a condition that can be associated with significant morbidity. Although previous research has been on predictive care pathways, scrutiny of the literature continues to reveal wide differences in the patient evaluation and management. The purpose of this study was to define the differences in joint aspiration for the evaluation of pediatric SA across pediatric tertiary care institutions in the United States.

Neonates with suspected microangiopathic disorders: performance of standard manual schistocyte enumeration vs. the automated fragmented red cell count

OBJECTIVES

To enhance the diagnosis of schistocyte-producing conditions, we compared routine manual schistocyte enumeration with automated fragmented red cell counts (FRCs).

STUDY DESIGN

In neonates "suspected" of having sepsis, NEC, or DIC we compared manual schistocyte estimates vs. automated FRC counts. When the two disagreed, we used a "gold standard" from a  ≥ 1000 RBC differential. We also assessed the diagnostic accuracy of the FRC count in diagnosing sepsis, NEC, or DIC.

RESULTS

We collected 270 CBCs from 90 neonates. The methods agreed in 63% (95% CI 55%-70%) of the CBCs. Among the 37% where they disagreed, the FRC count was more accurate in 100% (95% CI 88-100%). An elevated FRC count was specific for sepsis, and was sensitive and specific for necrotizing enterocolitis and DIC.

CONCLUSIONS

Automated FRC counts have advantages over routine manual evaluation, larger sample size, lower expense, and superior accuracy in diagnosing schistocyte-producing conditions.