Pediatric Laboratory Medicine

Polyphenol-stabilized coacervates for enzyme-triggered drug delivery

Stability issues in membrane-free coacervates have been addressed with coating strategies, but these approaches often compromise the permeability of the coacervate. Here we report a facile approach to maintain both stability and permeability using tannic acid and then demonstrate the value of this approach in enzyme-triggered drug release. First, we develop size-tunable coacervates via self-assembly of heparin glycosaminoglycan with tyrosine and arginine-based peptides. A thrombin-recognition site within the peptide building block results in heparin release upon thrombin proteolysis. Notably, polyphenols are integrated within the nano-coacervates to improve stability in biofluids. Phenolic crosslinking at the liquid-liquid interface enables nano-coacervates to maintain exceptional structural integrity across various environments. We discover a pivotal polyphenol threshold for preserving enzymatic activity alongside enhanced stability. The disassembly rate of the nano-coacervates increases as a function of thrombin activity, thus preventing a coagulation cascade. This polyphenol-based approach not only improves stability but also opens the way for applications in biomedicine, protease sensing, and bio-responsive drug delivery.

Tunisian Newborn's Cord Blood: Reference Values of Complete Blood Count and Hemoglobin Fractions

OBJECTIVE

This study was aimed to establish local reference values for hematological indices and hemoglobin (Hb) fractions in umbilical cord blood (UCB) for the northern population of Tunisia.

STUDY DESIGN

Our study included full-term newborns by vaginal deliveries. Hematological parameters were collected using an automated blood cell counter. The amounts of Hb fractions were measured by capillary electrophoresis of Hb. Statistical analysis was performed using R software.

RESULTS

A total of 328 cord blood samples were analyzed. Among them, 154 (male: 44.8%, female: 55.2%) were used to establish reference values. The normal reference values of complete blood count (CBC) and Hb fractions were calculated. Mean neonatal Hb was 14.75 ± 2.26 g/dL. Gestational age affects the expression of CBC values as red blood cell (RBC), Hb, hematocrit (Hct), mean corpuscular volume (MCV), white blood cell (WBC), and the Hb profile. Umbilical blood hemogram parameters and Hb profile are affected by the environment; higher in newborns from urban regions but not affected by gender ratio.

CONCLUSION

Reference ranges of normal CBC indices and Hb fractions have been successfully established in Tunisian neonates' UCB. Our data suggest reference values that could be useful for neonatal patients' laboratory results and clinical interpretation.

KEY POINTS

· Reference values for CBC and hemoglobin fractions have been established.. · Hematological reference for UCB is useful to identify hemolytic anemia cases early.. · UCB hematological values are influenced by gestational age and probably by environmental factors..

Capillary blood sampling increases the risk of preanalytical errors in pediatric hospital care: Observational clinical study

PURPOSE

The blood sampling procedure is complex and prone to failure, as reflected by preanalytical errors in pediatric hospital care. The primary aim was to evaluate if the risk of preanalytical errors was higher with capillary blood sampling than with venous blood sampling, and secondary, explore specific factors associated with preanalytical errors, both overall and stratified by capillary and venous blood sampling.

DESIGN AND METHODS

This observational pediatric hospital study collected outcomes from medical records and blood sampling surveys from year 2014 to 2016. The risk of preanalytical errors was analyzed with adjusted-odds ratio (adj-OR) by multivariable logistic regression with 95% confidence intervals (CIs).

RESULTS

Overall, 128 (13%) preanalytical errors were identified among 951 blood samples. The proportion and adj-OR of errors was significantly higher in capillary compared with venous blood samples, 72 (20%) of 354 versus 56 (9.4%) of 597, p = .001, adj-OR 2.88 (CI 1.79-4.64). Blood collection with multiple sample tubes was significantly associated with increased risk of preanalytical errors (n = 97 of 601, 16%), while log weight (kg) significantly decreased the risk of preanalytical errors adj-OR 0.66 (CI 0.50-0.86), indicating a protective effect of increasing weight. However, stratified analyses indicated a protective effect of increasing log weight for venous blood sampling adj-OR 0.52 (CI 0.38-0.72), but not capillary blood sampling, adj-OR 1.08 (CI 0.76-1.55).

CONCLUSION

This study indicates that capillary blood sampling collection increases the risk of preanalytical errors. Further, a child's increasing body weight reduced the risk of preanalytical errors, while multiple sample tube collections significantly increased the risk of preanalytical errors.

PRACTICE IMPLICATIONS

This new information may help nurses improve their knowledge concerning blood sampling collection in pediatrics. Altogether, this study also indicates that implementing more venous blood sampling and improve the cases of capillary sampling could reduce the number of preanalytical errors in pediatric hospitals.

A prospective, cross-sectional study to establish age-specific reference intervals for neonates and children in the setting of clinical biochemistry, immunology and haematology: the HAPPI Kids study protocol

INTRODUCTION

The clinical interpretation of laboratory tests is reliant on reference intervals. However, the accuracy of a reference interval is dependent on the selected reference population, and in paediatrics, the ability of the reference interval to reflect changes associated with growth and age, as well as sex and ethnicity. Differences in reagent formulations, methodologies and analysers can also impact on a reference interval. To date, no direct comparison of reference intervals for common analytes using different analysers in children has been published. The Harmonising Age Pathology Parameters in Kids (HAPPI Kids) study aims to establish age-appropriate reference intervals for commonly used analytes in the routine clinical care of neonates and children, and to determine the feasibility of paediatric reference interval harmonisation by comparing age-appropriate reference intervals in different analysers for multiple analytes.

METHODS AND ANALYSIS

The HAPPI Kids study is a prospective cross-sectional study, collecting paediatric blood samples for analysis of commonly requested biochemical, immunological and haematological tests. Venous blood samples are collected from healthy premature neonates (32-36 weeks of gestation), term neonates (from birth to a maximum of 72 hours postbirth) and children aged 30 days to ≤18 years (undergoing minor day surgical procedures). Blood samples are processed according to standard laboratory procedures and, if not processed immediately, stored at -80°C. A minimum of 20 samples is analysed for every analyte for neonates and then each year of age until 18 years. Analytical testing is performed according to the standard operating procedures used for clinical samples. Where possible, sample aliquots from the same patients are analysed for an analyte across multiple commercially available analysers.

ETHICS AND DISSEMINATION

The study protocol was approved by The Royal Children's Hospital, Melbourne, Ethics in Human Research Committee (34183 A). The study findings will be published in peer-reviewed journals and shared with clinicians, laboratory scientists and laboratories.

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.

UriSed - Preliminary reference intervals and optimal method for urine sediment analysis in newborns and infants

OBJECTIVES

The aim of this study was to establish reference intervals for urine sediment in newborns and infants in the second month of life for the UriSed automated analyser and for bright field microscopy. We also aimed to provide an optimal protocol for UriSed analysis, which best corresponds to the results of manual microscopy.

DESIGN AND METHODS

Urine sediment analyses of 75 healthy newborns and infants in the second month of life were performed by manual microscopy and UriSed automated analyser (two modes: 15 and 20 images per sample). Images were then reviewed and manually corrected by an operator when needed.

RESULTS

We observed statistically significant differences between bright-field microscopy and UriSed (when manual correction was not performed) for squamous epithelial cells and red blood cells counts (P<0.0001). There were no differences based on the number of images per sample (P>0.05). Upper reference values for bright-field microscopy and UriSed analyser taking 15 images per sample with manual correction (method we recommend) were as follows: squamous epithelial cells: microscope 8.7×10(6)/l, UriSed 6.4×10(6)/l, non-squamous epithelial cells: microscope 4.3×10(6)/l, UriSed 3.9×10(6)/l; erythrocytes: microscope 5.9×10(6)/l, UriSed: 4.6×10(6)/l; leukocytes: microscope 8.6×10(6)/l, UriSed 9.9×10(6)/l; hyaline casts: microscope 0×10(6)/l, UriSed (no correction) 0.7×10(6)/l.

CONCLUSIONS

We established preliminary reference intervals for urine sediment analysis in newborns and infants for UriSed and bright-field microscopy. We concluded that for routine laboratory examination of non-pathological urine it is enough to use the faster mode, with 15 images per sample, followed by a manual correction.

Early-Onset Neonatal Sepsis: Still Room for Improvement in Procalcitonin Diagnostic Accuracy Studies

To perform a systematic review assessing accuracy and completeness of diagnostic studies of procalcitonin (PCT) for early-onset neonatal sepsis (EONS) using the Standards for Reporting of Diagnostic Accuracy (STARD) initiative.EONS, diagnosed during the first 3 days of life, remains a common and serious problem. Increased PCT is a potentially useful diagnostic marker of EONS, but reports in the literature are contradictory. There are several possible explanations for the divergent results including the quality of studies reporting the clinical usefulness of PCT in ruling in or ruling out EONS.We systematically reviewed PubMed, Scopus, and the Cochrane Library databases up to October 1, 2014. Studies were eligible for inclusion in our review if they provided measures of PCT accuracy for diagnosing EONS. A data extraction form based on the STARD checklist and adapted for neonates with EONS was used to appraise the quality of the reporting of included studies.We found 18 articles (1998-2014) fulfilling our eligibility criteria which were included in the final analysis. Overall, the results of our analysis showed that the quality of studies reporting diagnostic accuracy of PCT for EONS was suboptimal leaving ample room for improvement. Information on key elements of design, analysis, and interpretation of test accuracy were frequently missing.Authors should be aware of the STARD criteria before starting a study in this field. We welcome stricter adherence to this guideline. Well-reported studies with appropriate designs will provide more reliable information to guide decisions on the use and interpretations of PCT test results in the management of neonates with EONS.

Development of paediatric biochemistry centile charts as a complement to laboratory reference intervals

Age-specific paediatric reference intervals are used in interpretation of laboratory results. However, interpretation may be problematic when a child just crosses an age bracket and the difference between the original and the subsequent age-specific reference interval is large. Moreover, details about the physiological changes with age may be masked. For the 12 months ending 30 September 2013, results of 16 common clinical biochemistry tests of ambulatory paediatric patients aged 0-19, requested by primary care physicians, were retrospectively collected in a large pathology service, and used to construct smoothed centile charts using a penalised maximum likelihood method. From the developed centile charts, the concentrations of sodium, bicarbonate, creatinine, urate, total protein, and albumin all increased with increasing age of the children. In contrast, the concentrations of potassium, chloride, anion gap, calcium, phosphate and lactate dehydrogenase decreased with increasing age of the children. Changes in the concentrations of urea, alkaline phosphatase, glucose, and total cholesterol varied by age. Generally, the boys and girls shared similar trend patterns until 10-15 years of age, when variations in the age of onset of puberty and development caused the trends of some biochemical measures to differ. The paediatric biochemistry centile charts are intuitive tools to use. They complement age-specific reference intervals in the tracking, interpretation and discussion of laboratory results. They also enhance the understanding of underlying physiological changes in biochemistry in children.

Reference intervals and age-related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

OBJECTIVE

To determine the reference interval for various venous analyte concentrations using a point-of-care (POC) analyzer in healthy, 4-84-day-old puppies and identify any age-specific variations in the values as compared with adults.

DESIGN

A prospective cohort study.

SETTING

University teaching hospital.

ANIMALS

Clinically healthy dogs; 68 puppies and 30 adults.

MEASUREMENTS AND MAIN RESULTS

Samples were collected by jugular venipuncture from 68 clinically healthy puppies at 4, 10, 12, 16, 28, 70, 77, and 84 days of age and once each from 30 clinically healthy adult dogs. Blood samples (n = 287) were analyzed within 5 minutes of collection using an automated POC analyzer. Reference intervals for puppies at various ages were estimated using a bootstrap sampling approach. The analytes that were closest to the adult values were pH and bicarbonate. On days 4 and 10 the pH for puppies was higher than the adults while the HCO3 was higher than the adults only on day 4. HCT on day 4 approximated adult values but fell to a nadir on day 28 before rising toward adult levels. At all time points, sodium, chloride, and ionized magnesium concentrations were lower than adult values, and potassium and ionized calcium were higher than adult values. Glucose was similar to adult values on day 4 but was above adult values at all other time points. Blood urea nitrogen (BUN) was higher in puppies until day 28 when it became lower than in adults. BUN levels remained lower than adults through day 84.

CONCLUSIONS

Variations exist between puppies and adults for venous POC analyzer results. Adult reference intervals should not be used for puppies as this might cause misinterpretation of the results.

Preanalytical quality improvement: in quality we trust

Total quality in laboratory medicine should be defined as the guarantee that each activity throughout the total testing process is correctly performed, providing valuable medical decision-making and effective patient care. In the past decades, a 10-fold reduction in the analytical error rate has been achieved thanks to improvements in both reliability and standardization of analytical techniques, reagents, and instrumentation. Notable advances in information technology, quality control and quality assurance methods have also assured a valuable contribution for reducing diagnostic errors. Nevertheless, several lines of evidence still suggest that most errors in laboratory diagnostics fall outside the analytical phase, and the pre- and postanalytical steps have been found to be much more vulnerable. This collective paper, which is the logical continuum of the former already published in this journal 2 years ago, provides additional contribution to risk management in the preanalytical phase and is a synopsis of the lectures of the 2nd European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)-Becton Dickinson (BD) European Conference on Preanalytical Phase meeting entitled "Preanalytical quality improvement: in quality we trust" (Zagreb, Croatia, 1-2 March 2013). The leading topics that will be discussed include quality indicators for preanalytical phase, phlebotomy practices for collection of blood gas analysis and pediatric samples, lipemia and blood collection tube interferences, preanalytical requirements of urinalysis, molecular biology hemostasis and platelet testing, as well as indications on best practices for safe blood collection. Auditing of the preanalytical phase by ISO assessors and external quality assessment for preanalytical phase are also discussed.

Upper limit of normal for alanine aminotransferase: quo vadis?

Several studies suggest that a substantial number of patients with normal serum alanine aminotransferase (ALT) levels, defined by current thresholds, have ongoing hepatic necro-inflammation and fibrosis, and are at risk of liver disease progression. A major problem lies in the definition of normality. The current upper limit of normal (ULN) for ALT was established in the 1980s when reference populations were likely to include many persons with hepatitis C virus infection and nonalcoholic fatty liver disease. Because ALT may be influenced, not only by liver disease, but also by other medical conditions, changing lifestyle factors and demographic determinants, the current ALT ULN threshold has recently been challenged. This review not only highlights current evidence on why and how ALT ULN should be redefined, but also discusses the current concerns about updating the ULN threshold for ALT.

Procalcitonin in pediatrics

Over the past two decades, the body of literature on the clinical usefulness of procalcitonin (PCT) in adults has grown rapidly. Although this approach has led to increased insight, it has also prompted debate regarding its potential use in diagnosis and management of severe infection. Clinicians, however, are less familiar with the use of PCT in pediatric populations. In this review, we examine PCT as a marker of severe clinical pediatric conditions including its role in systemic inflammation, infection, and sepsis.

Klinische Methoden

Die Anamnese kranker Kinder ist überwiegend eine Fremdanamnese der Mutter, des Vaters oder einer Pflegeperson. Mit dem Älterwerden und besonders in der Pubertät wächst der Anspruch des kindlichen Patienten, das Gespräch selbst zu gestalten.

Some general considerations about the clinicopathologic aspects of soft tissue tumors in children and adolescents

Soft tissue tumors in children and adolescents are an important group of neoplasms, pseudoneoplasms, and tumefactive malformations with some distinctive clinicopathologic, genetic, syndromic, and therapeutic implications. In addition to the basic pathologic examination, there is the availability of diagnostic adjuncts in various settings based upon the histopathologic features that facilitate and/or corroborate a diagnosis. Immunohistochemistry, cytogenetics, molecular genetics, and an ever-increasing array of new technologies are available to address specific diagnostic questions and even potential therapeutic strategies. This review focuses upon some of the unique aspects of soft tissue tumors in children, including the classification, approach to the diagnosis, grading, clinical and pathologic staging, therapy-related changes, pathogenesis, and risk factors.

High performance liquid chromatography evaluation of serum carbohydrate-deficient transferrin and more sialylated transferrin glycoforms in children

OBJECTIVES

The evaluation of the age-specific distribution of transferrin glycoforms in paediatric patients may help in defining reference intervals which are critical for an improved and earlier diagnosis.

DESIGN AND METHODS

Serum samples from 224 children (age: 2 months-14 years) were analyzed by HPLC (Bio-Rad CDT/HPLC kit) and glycoforms expressed as percentage of the total area of transferrin (Tf).

RESULTS

Asialo- and Monosialo-Tf were not detectable in any patient. Medians (IQR) were respectively 0.92% (0.80-1.04%) for Disialo-Tf; 3.47% (2.69-4.18%) for Trisialo-Tf; 82.54% (81.32-83.53%) for Tetrasialo-Tf; 12.73% (11.91-14.09%) for Pentasialo-Tf. Statistically significant differences in Trisialo-Tf (p < 0.0005), Tetrasialo-Tf (p = 0.001), Pentasialo-Tf (p < 0.0005), but not in Disialo-Tf, were observed between the age groups.

CONCLUSIONS

Age-specific Disialo-Tf cut-offs are not necessary. In children 1.3% and 6.4% may be suggested as upper limits of normal range to detect increases of Disialo- and Trisialo-Tf. The presence of Asialo- and Monosialo-Tf should be considered an abnormal finding and prompt further investigations.

Issues in neonatal cellular analysis

Hematologic values in neonates differ significantly from those in older children and adults. Quantitative and qualitative differences are present as a reflection of the developmental changes during fetal hematopoiesis and, so, correlate with gestational age. At birth, the hemoglobin, mean corpuscular volume, and WBC counts of term newborns are significantly higher than those of older children and adults, and in preterm neonates the differences are even more pronounced. This review explores these differences and the major factors that account for them from the hematology laboratory standpoint. After a discussion of the developmental hematopoiesis and normal hematologic values in term and preterm neonates, important preanalytic factors, such as limited blood availability, effect of sampling site, and violent crying, and analytic interferences are examined. Finally, the review addresses resulting challenges in interpretation of hematologic test results in term and preterm neonates, especially issues surrounding neonatal reference intervals and critical value reporting, and suggests possible solutions.

Teaching Pediatric Laboratory Medicine to Pathology Residents

Context.—Laboratory data are essential to the medical care of fetuses, infants, children, and adolescents. However, the performance and interpretation of laboratory tests on specimens from these patients, which may constitute a significant component of the workload in general hospitals and integrated health care systems as well as specialized perinatal or pediatric centers, present unique challenges to the clinical pathologist and the laboratory. Therefore, pathology residents should receive training in pediatric laboratory medicine.

Objective.—Children's Health Improvement through Laboratory Diagnostics, a group of pathologists and laboratory scientists with interest and expertise in pediatric laboratory medicine, convened a task force to develop a list of curriculum topics, key resources, and training experiences in pediatric laboratory medicine for trainees in anatomic and clinical pathology or straight clinical pathology residency programs and in pediatric pathology fellowship programs.

Data Sources.—Based on the experiences of 11 training programs, we have compiled a comprehensive list of pediatric topics in the areas of clinical chemistry, endocrinology, hematology, urinalysis, coagulation medicine, transfusion medicine, immunology, microbiology and virology, biochemical genetics, cytogenetics and molecular diagnostics, point of care testing, and laboratory management. This report also includes recommendations for training experiences and a list of key texts and other resources in pediatric laboratory medicine.

Conclusions.—Clinical pathologists should be trained to meet the laboratory medicine needs of pediatric patients and to assist the clinicians caring for these patients with the selection and interpretation of laboratory studies. This review helps program directors tailor their curricula to more effectively provide this training.