Preliminary Investigation into the Prevalence of G6PD Deficiency in a Pediatric African American Population Using a Near-Patient Diagnostic Platform.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent in the African American population. We identified eighteen G6PD-deficient samples (9%) in a study of residual, de-identified whole blood specimens from 200 African American pediatric patients using a point-of-care instrument. This highlights the possibility of a rapid time to result for G6PD testing, which can be valuable in some clinical scenarios.

Single-cell RNA sequencing distinctly characterizes the wide heterogeneity in pediatric mixed phenotype acute leukemia.

BACKGROUND: Mixed phenotype acute leukemia (MPAL), a rare subgroup of leukemia characterized by blast cells with myeloid and lymphoid lineage features, is difficult to diagnose and treat. A better characterization of MPAL is essential to understand the subtype heterogeneity and how it compares with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Therefore, we performed single-cell RNA sequencing (scRNAseq) on pediatric MPAL bone marrow (BM) samples to develop a granular map of the MPAL blasts and microenvironment landscape. METHODS: We analyzed over 40,000 cells from nine pediatric MPAL BM samples to generate a single-cell transcriptomic landscape of B/myeloid (B/My) and T/myeloid (T/My) MPAL. Cells were clustered using unsupervised single-cell methods, and malignant blast and immune clusters were annotated. Differential expression analysis was performed to identify B/My and T/My MPAL blast-specific signatures by comparing transcriptome profiles of MPAL with normal BM, AML, and ALL. Gene set enrichment analysis (GSEA) was performed, and significantly enriched pathways were compared in MPAL subtypes. RESULTS: B/My and T/My MPAL blasts displayed distinct blast signatures. Transcriptomic analysis revealed that B/My MPAL profile overlaps with B-ALL and AML samples. Similarly, T/My MPAL exhibited overlap with T-ALL and AML samples. Genes overexpressed in both MPAL subtypes' blast cells compared to AML, ALL, and healthy BM included MAP2K2 and CD81. Subtype-specific genes included HBEGF for B/My and PTEN for T/My. These marker sets segregated bulk RNA-seq AML, ALL, and MPAL samples based on expression profiles. Analysis comparing T/My MPAL to ETP, near-ETP, and non-ETP T-ALL, showed that T/My MPAL had greater overlap with ETP-ALL cases. Comparisons among MPAL subtypes between adult and pediatric samples showed analogous transcriptomic landscapes of corresponding subtypes. Transcriptomic differences were observed in the MPAL samples based on response to induction chemotherapy, including selective upregulation of the IL-16 pathway in relapsed samples. CONCLUSIONS: We have for the first time described the single-cell transcriptomic landscape of pediatric MPAL and demonstrated that B/My and T/My MPAL have distinct scRNAseq profiles from each other, AML, and ALL. Differences in transcriptomic profiles were seen based on response to therapy, but larger studies will be needed to validate these findings.

Leukoerythroblastosis as an Unusual Presentation of Parvovirus B19 Infection in a Sickle Cell Patient.

Parvovirus B19 infection in pediatrics most commonly causes fifth disease, a mild viral illness. Hematologic manifestations include severe anemia, especially in patients with chronic hemolytic anemias or who are immunocompromised. Because of the shortened life span of erythrocytes in patients with sickle cell disease, parvovirus infection can cause transient aplastic crisis which can be life-threatening. However, leukocytosis and thrombocytosis are rarely seen. We report leukoerythroblastosis as an unusual presentation of acute parvovirus B19 infection in a previously splenectomized 12-year-old boy with sickle cell disease.

The Impact of Disruption of the Care Delivery System by Commercial Laboratory Testing in a Children's Health Care System.

CONTEXT.­: Disruption of outpatient laboratory services by routing the samples to commercial reference laboratories may seem like a cost-saving measure by the payers, but results in hidden costs in quality and resources to support this paradigm. OBJECTIVE.­: To identify differences when outpatient tests are performed at the Children's Healthcare of Atlanta (Children's) Hospital lab compared to a commercial reference lab, and the financial costs to support the reference laboratory testing. DESIGN.­: Outpatient testing was sent to 3 different laboratories specified by the payer. Orders were placed in the Children's electronic health record, blood samples were drawn by the Children's phlebotomists, samples were sent to the testing laboratory, and results appeared in the electronic health record. Data comparing the time to result, cancelled samples, and cost to sustain the system of ordering and reporting were drawn from multiple sources, both electronic and manual. RESULTS.­: The median time from phlebotomy to result was 0.7 hours for testing at the Children's lab and 20.72 hours for the commercial lab. The median time from result posting to caregiver acknowledgment was 5.4 hours for the Children's lab and 18 hours for the commercial lab. The commercial lab cancelled 2.7% of the tests; the Children's lab cancelled 0.8%. The financial cost to support online ordering and reporting for testing performed at commercial labs was approximately $640,000 per year. CONCLUSIONS.­: Tangible monetary costs, plus intangible costs related to delayed results, occur when the laboratory testing system is disrupted.

Comparison of Alere i Strep A Rapid Molecular Assay With Rapid Antigen Testing and Culture in a Pediatric Outpatient Setting.

OBJECTIVES: Group A Streptococcus (GAS) is the most common bacterial cause of pediatric acute pharyngitis, and its quick identification is important for subsequent treatment. We sought to determine whether molecular GAS-based testing can successfully replace GAS antigen testing and subsequent culture in a pediatric urgent care center. METHODS: We tested 160 patient oropharyngeal samples by a rapid antigen GAS test, the Alere i Strep A test, and throat culture in a pediatric urgent care setting and calculated basic statistical metrics. RESULTS: The sensitivity and specificity of the molecular test were 98% and 100%, respectively, compared with culture. There was a 9% false-positive rate with the rapid antigen-based testing. CONCLUSIONS: The Alere test is sufficiently sensitive and specific for definitive GAS testing in a pediatric urgent care setting. This implementation has enabled us to provide definitive patient results at the time of each patient encounter.

Validation of an Enclosed Blood Collection System in a Pediatric Laboratory.

BACKGROUND: Preanalytical, analytical, and postanalytical issues are often magnified in pediatric laboratories, and traditional vacuum-based blood tubes can contribute to some of these issues. Because of this, we investigated adopting an enclosed blood collection system that can perform vacuum or gentle aspiration blood collection, eliminating syringes, transfer device, and transfer steps, as well as potentially minimizing preanalytical error in the pediatric laboratory. We embarked on a validation of this tube system, in comparison with our current collection tubes, across most in-house tests at a large pediatric hospital. METHODS: Twenty adult volunteers were recruited. Blood was drawn into lithium heparin, serum, EDTA, and citrate tubes of each commercial tube type for comparison. For some tests, remnant blood from pediatric syringe draws was used when available. Samples were then processed and analyzed across all general areas of the clinical laboratory, and correlations of the results from the 2 tube systems were performed. RESULTS: Across 95 tests in the core laboratory and blood bank, almost all demonstrated clinically acceptable comparisons, with most R values >0.90. Only 3 of 95 tests demonstrated clinically significant differences between the tube systems. CONCLUSIONS: Our validation of the enclosed blood collection system demonstrated acceptable results when compared with our current collection tubes. Additionally, with some minor modifications, our automated instruments could utilize ultralow-volume tubes from the enclosed blood collection system for direct tube sampling, which is impossible using our current small-volume tubes with our main chemistry analyzer.

Relating prognosis in chromophobe renal cell carcinoma to the chromophobe tumor grading system.

PURPOSE: The chromophobe subtype of renal cell carcinoma (chRCC) has generally been associated with a better prognosis than the clear cell type; however, debate continues as to absolute prognosis as well as the significance of certain prognostic variables. We investigated the significance of pathologic stage and a recently proposed chromophobe tumor grading (CTG) scheme in predicting chRCC outcomes. MATERIALS AND METHODS: All available chRCCs were identified from our surgical pathology archives from 1987-2010. Original slides were reviewed to verify diagnoses and stage, and each case was graded following a novel chromophobe tumor grade system criteria. Disease status was obtained from a clinical outcome database, and cancer specific deaths and recurrences were recorded. RESULTS: Eighty-one cases of chRCC were identified, and 73 had adequate follow-up information available. There were only 3 instances of cancer related recurrence or mortality, which included 1 disease specific mortality and 2 disease recurrences. Pathologic stage and CTG 3 were found to be significantly associated with the recurrences or death from chRCC, but there was no association with CTG 1 and CTG 2. CONCLUSIONS: chRCC is associated with a very low rate of cancer specific events (4.1%) even at a tertiary referral center. In our study, pathologic stage and CTG 3, but not CTG 1 or 2, were significantly associated with the development of these events.

Bone marrow evaluation in new-onset pancytopenia.

The new onset of pancytopenia often creates a diagnostic dilemma to the treating physician and leads to bone marrow biopsy and aspiration. To determine the distribution of bone marrow findings in such cases of new-onset pancytopenia in a tertiary academic medical center, we evaluated 250 recent bone marrow aspirates and biopsies performed in the setting of new-onset pancytopenia in patients without previously diagnosed hematologic neoplastic disease. Of the 250 bone marrow studies, 193 were performed in adults and 57 were performed in children. In children, the most prevalent bone marrow finding was B-lymphoblastic leukemia, followed by nonspecific changes attributed clinically to a variety of factors including multifactorial, autoimmune, inflammatory, and infectious etiologies. In adults, hematologic neoplastic causes of pancytopenia were the most prevalent diagnoses, with the cases divided mostly between acute myeloid leukemia and myelodysplastic syndrome, with fewer numbers of cases of acute lymphoblastic leukemia, myeloproliferative neoplasms, and lymphomas. Many bone marrow findings demonstrated nonspecific changes that were attributed clinically to a variety of etiologies such as myelodysplastic syndrome, multifactorial causes, hypersplenism, drugs, and systemic disease. Overall, in both the pediatric and the adult population, new-onset pancytopenia was most commonly associated with neoplasia, although the neoplasm differed by age group. Although in most cases, a definitive diagnosis could be made based solely on bone marrow aspirate and biopsy interpretation, a significant fraction of cases in both children and adults demonstrated nonspecific marrow findings that required clinical follow-up and/or repeat biopsy for definitive diagnosis.

The differential diagnosis and bone marrow evaluation of new-onset pancytopenia.

New-onset pancytopenia can be caused by a wide variety of etiologies, leading to a diagnostic dilemma. These etiologies range from congenital bone marrow failure to marrow space-occupying lesions, infection, and peripheral destruction, to name a few. Bone marrow examination, in addition to a detailed clinical history, is often required for an accurate diagnosis. The purpose of this review is to provide a brief overview of many of the causes of new-onset pancytopenia in adults and children, with emphasis on bone marrow findings and recommendations of additional testing and clinical evaluation when needed, with the overall aim of aiding the pathologist's role as a consultant to the patient's treating physician.