Performance of OC-Auto Micro 80 Fecal Immunochemical Test in an Integrated Academic-Community Health System

GOALS

We aimed to determine the performance of the OC-Auto Micro 80 fecal immunochemical test (FIT) in an average-risk population receiving care in an integrated, academic-community health system.

BACKGROUND

The FIT is the most used colorectal cancer (CRC) screening test worldwide. However, many Food and Drug Administration-cleared FIT products have not been evaluated in clinical settings.

STUDY

We performed a retrospective cohort study of patients (50 to 75 y old) in the University of Washington Medicine health care system who were screened for CRC by OC-Auto Micro 80 FIT between March 2016 and September 2021. We used electronic health records to extract patient-level and clinic-level factors, FIT use, colonoscopy, and pathology findings. The primary outcomes were the FIT positivity rate and neoplasms detected at colonoscopy. Secondary outcomes were FIT positivity by sex and safety-net versus non-safety-net clinical settings.

RESULTS

We identified 39,984 FITs completed by 26,384 patients; 2411 (6.0%) had a positive FIT result (>100 ng/mL of hemoglobin in buffer), and 1246 (51.7%) completed a follow-up colonoscopy. The FIT positive rate was 7.0% in men and 5.2% in women (P <0.01). Among those who completed a colonoscopy after an abnormal FIT result, the positive predictive value for CRC, advanced adenoma, and advanced neoplasia was 3.0%, 20.9%, and 23.9%, respectively.

CONCLUSIONS

In a retrospective analysis of a large heterogeneous population, the OC-Auto Micro 80 FIT for CRC screening demonstrated a positivity rate of 6.0% and a positive predictive value for CRC of 3.0%.

Endogenous, non-reducing end glycosaminoglycan biomarkers are superior to internal disaccharide glycosaminoglycan biomarkers for newborn screening of mucopolysaccharidoses and GM1 gangliosidosis

Measurement of enzymatic activity in newborn dried blood spots (DBS) is the preferred first-tier method in newborn screening (NBS) for mucopolysaccharidoses (MPSs). Our previous publications on glycosaminoglycan (GAG) biomarker levels in DBS for mucopolysaccharidosis type 1 (MPS-I) and MPS-II demonstrated that second-tier GAG biomarker analysis can dramatically reduce the false positive rate in NBS. In the present study, we evaluate two methods for measuring GAG biomarkers in seven MPS types and GM1 gangliosidosis. We obtained newborn DBS from patients with MPS-IIIA-D, -IVA, -VI, -VII, and GM1 gangliosidosis. These samples were analyzed via two GAG mass spectrometry methods: (1) The internal disaccharide biomarker method; (2) The endogenous non-reducing end (NRE) biomarker method. This study supports the use of second-tier GAG analysis of newborn DBS by the endogenous NRE biomarker method, as part of NBS to reduce the false positive rate.

Benzodiazepine analysis by an improved LC-MS/MS method illustrates usage patterns in Washington State

BACKGROUND

The standard approach for benzodiazepine detection often includes immunoassay followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The illicit use of non-prescribed benzodiazepines has been trending up nationally.

METHODS

We developed and validated an improved LC-MS/MS assay for benzodiazepine detection in urine. We expanded the testing panel by adding five drugs to the previous panel of ten. We determined the prevalence of individual benzodiazepines in our patient population. Immunoassay results were compared with LC-MS/MS to evaluate assay performance.

RESULTS

Clonazepam and alprazolam were the most common benzodiazepines present. Etizolam and flualprazolam were also prevalent in Washington State. Compared with the LC-MS/MS assay, the immunoassay had variable cross-reactivity, which explained false negative and false positive immunoassay results. The inclusion of new drugs in the LC-MS/MS panel significantly reduced the incidence of immunoassay results interpreted as falsely positive.

CONCLUSION

New illicit benzodiazepines have emerged regionally and nationally. The inclusion of novel drugs in LC-MS/MS assay was helpful in properly characterizing the epidemiology of benzodiazepine use in our patient population. This information will lead to better assay result interpretations and patient care, and our experiences provide a roadmap for other clinical laboratories looking to expand their testing menu or transition to new instrumentation.

Laboratory Test Ordering Patterns in Pediatrics From Naturopaths and General Practitioners

OBJECTIVES

Naturopathic medicine emphasizes prevention and the self-healing process through natural therapies. Naturopathic doctors (NDs) use clinical laboratories as frequently as traditionally trained physicians. Here we evaluated the test-ordering patterns of NDs and general practitioners (GPs).

METHODS

A retrospective analysis was performed from a tertiary pediatric hospital. We analyzed tests ordered by NDs who used laboratory services and compared the test ordering patterns with GPs from adolescent medicine, family medicine, or pediatric clinics. Requests were categorized into 10 groups. We determined the tests with the highest ordering frequencies, as well as the percentage of tests that had an abnormal result.

RESULTS

NDs ordered more tests per patient per date of specimen collection compared with GPs. The most frequently ordered tests by NDs were trace elements and toxic metals (23.2% of total), allergens (21.8%), and general chemistry (15.3%). For the same test, the percentage of tests with an abnormal result was significantly lower for NDs than GPs.

CONCLUSIONS

We observed different ordering patterns between NDs and GPs. NDs ordered more esoteric tests and had lower rates of abnormal test results compared with GPs. Understanding the patterns of testing from different providers' specialties is useful to choose effective laboratory stewardship interventions.

Galactocerebrosidase activity by liquid-chromatography tandem mass spectrometry for clinical diagnosis of Krabbe disease

BACKGROUND

Deficiency of galactosylcerebrosidase (GALC) causes Krabbe disease. Historically, a diagnosis is made by measuring GALC enzymatic activity with a radioisotope assay. To improve the workflow and performance, we developed and clinically validated a leukocyte enzymatic assay using liquid chromatography tandem mass spectrometry (LC-MS/MS).

MATERIALS

Extracted cell lysates were quantified and incubated with commercially available multiplexed substrates and internal standards. Liquid-liquid extraction was performed, and pre-analytical and analytical variability were evaluated and validated following clinical laboratory regulation guidelines.

RESULTS

Enzymatic reaction products were resolved from substrate breakdown products by a 3.5-minute column separation. Intra- and inter- assay imprecision were less than 15%. No matrix effects or carryover were observed. ACD anticoagulant tubes provide the best sample stability. Detection of product was linear with an R² of 0.99. Small differences in GALC activity were measurable near the anticipated disease range. Confirmed cases of Krabbe disease were well differentiated from carriers and non-Krabbe individuals (normal reference range).

CONCLUSION

An LC-MS/MS assay was developed, which can measure trace residual GALC activity in leukocytes and aid in the diagnosis of Krabbe disease. The multiplexed mixture allows for built-in sample quality control and enables a streamlined workflow for evaluation of multiple lysosomal storage diseases.

Development and Validation of Leukocyte Enzyme Activity Assay by LC-MS/MS for Diagnosis of Krabbe Disease and Other Lysosomal Storage Diseases

Background

Deficiency of the lysosomal enzyme galactosylcerebrosidase (GALC) causes Krabbe disease. The diagnosis for Krabbe disease includes measurement of GALC enzymatic activity by radioisotope assay or accumulation of metabolite psychosine. To improve current diagnostic workflow and assay performance, we developed and validated a leukocyte enzymatic assay by using liquid chromatography tandem mass spectrometry (LC-MS/MS) for lysosomal storage diseases.

Methods

Leukocytes were separated and extracted from whole blood samples, and total protein was quantitated by BCA method. Commercialized and multiplexed substrates, internal standards, and buffer were incubated with cell lysates. The lysosomal enzymes in leukocytes metabolized the artificial substrate into product which is structurally identical to the internal standard. Liquid-liquid extraction was performed and supernatant was dried down and reconstituted. Liquid chromatography separation was achieved by Waters CSH C18, 2.1 x 50 mm column and Acquity UPLC system. A Waters Xevo TQS tandem mass spectrometer was used for mass detection.

Results

Enzymatic reaction products for six lysosomal enzymes were chromatographically resolved from substrate breakdown products through 3.5 minutes gradient liquid chromatography. Intra-assay imprecision was determined by 11 replicates of samples containing low and high concentration (CV&lt;15%). Carryover was determined by assaying triplicates of cell lysate-free cocktails directly after injection of high enzyme activity sample (less than 0.1%). No matrix effect was found. The GALC enzyme activity was calculated and standardized by corresponding product and internal standard ratios from 5-point standard curve. The range of enzyme activity from three, known affected patients is 0.01–0.07 (nmol/hr/mg protein); whereas, two identified carriers had enzyme activate in the range of 0.14–0.40 (nmol/hr/mg protein). The reference interval was established from 63 residual, unaffected samples and was 0.12–5.97 (1.44±1.44) nmol/hr/mg protein.

Conclusions

A simple and multiplexed LC-MS/MS assay was developed which can measure small amounts of residual GALC enzyme activity in leukocytes. This confirmatory assay will aid in the diagnosis and prognosis (i.e. differentiate disease severity) of Krabbe disease and other lysosomal storage disorders.

A Comparison of Ordering Pattern of Laboratory Send-Out Tests Between Naturopathic Doctors and General Practitioners in a Pediatric Population

Objectives

Naturopathy is defined as the practice of medicine for the treatment of human diseases with natural agents. It also emphasizes prevention and promotion of health through the self-healing process of the body. Even without any illness or symptoms, naturopathic doctors (NDs) often advocate for and use unique lab tests to make clinical judgments. Tests that are performed outside of the ordering institution, send-out tests, are at increased risk of ordering the wrong or unnecessary test and misinterpreting test results. Here we evaluate the laboratory send-out tests that were ordered by NDs and general practitioners (GPs) at a tertiary pediatric care center to identify opportunities for improved laboratory stewardship.

Methods

We performed a retrospective analysis from Seattle Children’s laboratory send-out tests, which were ordered between January 1, 2018, and December 31, 2018. We compared the tests ordered by NDs with general practitioners in our practice, by grouping the following provider specialties: adolescent medicine, family medicine, or pediatrics. All the requests were reviewed and categorized by test type: heavy metal, allergen, infectious disease, hormone and vitamin, hematology and immunology, toxicology, oncology, genetics, and others. Ordering frequency and abnormal rate from each category were analyzed. The abnormal rate was defined as percentage of abnormal results divided by total number of ordered tests.

Results

During the 12-month period, there were 20,312 send-out tests; 1,028 (5.1%) of them were ordered by 83 NDs for 329 patients, and 3,862 (19.0%) of them were ordered by 462 GPs for 2,139 patients. The most frequently ordered tests by NDs were heavy metal screens (506 tests, 49.2% of total), allergen panels (31.7%), and infectious disease tests (7.0%). The corresponding abnormal rates were 8.5%, 0.9%, and 8.3%, respectively, with an overall abnormal rate of 6.6%. For GPs, the most frequently ordered tests were hormone and vitamin analyses (1,346 tests, 34.9% of total), hematology and immunology tests (22.5%), and heavy metal screens (10.8%). The corresponding abnormal rates were 18.1%, 35.9%, and 18.8% and overall abnormal rate was 17.8%.

Conclusion

We observed different ordering patterns between GPs and NDs, with rates of abnormal findings significantly higher from the tests ordered by GPs. These data suggest some of the tests ordered by NDs have low positive predictive value or clinical significance and could be potentially mis- or overutilized. Understanding the patterns and the variety of testing from different providers can help target interventions to improve laboratory stewardship in this area.

Twelve-Hour Urine Collection Can Be Utilized to Estimate 24-Hour Total Urinary Nitrogen in Critically Trauma Patients

Patients suffering from trauma, burns, and sepsis are frequently in a hypermetabolic state, and as the majority of urinary nitrogen comes from amino acid metabolism, the determination of total urinary nitrogen (TUN) provides an accurate measurement of all nitrogen excreted in urine and can be used as an indicator of catabolic stress. To evaluate whether time of collection influences the performance of TUN test, 12-hour urine specimens were collected from ICU trauma patients and the 12-hour results were correlated with results from 24-hour collections.

Two consecutive 12-hour urine samples were collected (06:00-18:00 hours and 18:00-06:00 hours) from surgical ICU patients. Total urinary nitrogen levels were measured in each 12-hour sample, as well as in a pooled sample (24 hours). Pyrochemiluminescence was used to determine TUN level on an Antek 9000N elemental analyzer. In this approach, the urine sample is completely oxidized at high temperature in a quartz pyrotube. Nitrogen is converted to nitric oxide (·NO), then mixed with O3 (ozone) to form nitrogen dioxide (NO2). Light is emitted and specific wavelengths between 650 and 900 nm were measured in a photomultiplier tube. The measured chemiluminescent emission is specific and proportional to the amount of nitrogen in the sample.

Fifty 12-hour urine samples from 16 patients were collected. One patient was excluded from the study due to acute renal injury during the collection period. There was no significant observed circadian effect on measured TUN. The 12-hour TUN (g/total volume) was multiplied by 2 to compare to 24-hour TUN for statistical analysis. There was strong correlation between either day or night 12-hour TUN and corresponding pooled 24-hour TUN, with correlation coefficients ranging from 0.93 to 0.98 and regression slopes ranging from 0.98 to 1.01. No statistically significant difference was found between the 12-hour TUN and 24-hour TUN approaches.

A 12-hour TUN collection was overall highly predictive of 24-hour TUN collection and has the advantage of convenience of sample collection and improved clinical efficiency. Serial 12-hour urine collection is therefore preferred for monitoring nitrogen balance and adjusting protein intake for critically ill ICU patients.

Very rare condition of multiple Gaucheroma: A case report and review of the literature

Background

This study presented a 3 years old boy with Gaucher disease (GD) who was treated with enzyme replacement therapy(ERT) for 19 months and developed multiple Gaucheroma. The literature was reviewed.

Methods

The medical chart and literature were reviewed. A boy presented at the age of 15 months with anemia, thrombocytopenia, and hepatosplenomegaly. Enzyme assay and gene mutations confirmed GD. ERT was administered. When the boy was 3 years old, multiple masses were discovered from abdominal MRI and biopsy revealed Gaucheroma. We reviewed 20 GD patients with Gaucheroma and Gaucher cell infiltrated lymphadenopathies.

Conclusion

Gaucheroma is a rare condition in regularly treated GD patients. This patient showed poor response to doubled ERT doses. The imaging studies are necessary for Gaucher patients to detect Gaucheroma and determine their malignancy. Regular checkups are recommended in all GD patients even with ERT treatment, due to the possibility of having a deteriorating change, like Gaucheroma.

Very rare condition of multiple Gaucheroma: A case report and review of the literature

Background

This study presented a 3 years old boy with Gaucher disease (GD) who was treated with enzyme replacement therapy (ERT) for 19 months and then developed multiple Gaucheroma. Review of literature was performed simultaneously.

Methods

The medical chart and literature were reviewed. A boy presented at the age of 15 months with anemia, thrombocytopenia, and hepatosplenomegaly. GD was confirmed by enzyme assay and gene mutations. ERT was administered right after the diagnosis. When the boy was 3 years old, multiple masses were discovered during a regular checkup abdominal MRI and biopsy revealed Gaucheroma. We also reviewed 20 GD patients with Gaucheroma and Gaucher cell infiltrated lymphadenopathies.

Conclusion

Gaucheroma is a rare condition of regularly treated GD patients. This patient even showed poor response to doubled ERT doses. The imaging studies are necessary for Gaucher patients to detect Gaucheroma and determine their malignancy. Regular checkups are recommended in all GD patients even with regular treatment, due to the possibility of having deteriorating change, like Gaucheroma.

Methylmalonic acidemia/propionic acidemia - the biochemical presentation and comparing the outcome between liver transplantation versus non-liver transplantation groups

Background

Most patients with isolated methylmalonic acidemia (MMA) /propionic acidemia (PA) presenting during the neonatal period with acute metabolic distress are at risk for death and significant neurodevelopmental disability. The nationwide newborn screening for MMA/PA has been in place in Taiwan from January, 2000 and data was collected until December, 2016.

Results

During the study period, 3,155,263 newborns were screened. The overall incidence of MMA mutase type cases was 1/121,356 (n = 26), 1 cobalamin B was detected and that for PA cases (n = 4) was 1/788,816. The time of referral is 8.8 days for MMA patients, and 7.5 days for PA patients. The MMA mutase type patients have higher AST, ALT, and NH₃ values as well as a lower pH value (p < 0.05). The mean age for liver transplantation (LT) is 402 days (range from 0.6–6.7 yr) with 16 out of 20 cases (80.0%) using living donors. The mean admission length shortened from 90.6 days/year (pre-LT) to 5.3 days/year (at 3rd year post-LT) (p < 0.0005). Similarly, the tube feeding ratio decreased from 67.8 to 0.50% (p < 0.00005). The anxiety level of the caregiver was reduced from 33.4 to 27.2 after LT (p = 0.001) and the DQ/IQ performance of the patients was improved after LT from 50 to 60.1 (p = 0.07).

Conclusion

MMA/PA patients with LT do survive and have reduced admission time, reduced tube feeding and the caregiver is less anxious.

Taiwan National Newborn Screening Program by Tandem Mass Spectrometry for Mucopolysaccharidoses Types I, II, and VI

OBJECTIVE

To evaluate the initial cutoff values, rates of screen positives, and genotypes for the large-scale newborn screening program for multiple mucopolysaccharidoses (MPS) in Taiwan.

STUDY DESIGN

More than 100 000 dried blood spots were collected consecutively as part of the national Taiwan newborn screening programs. Enzyme activities were measured by tandem mass spectrometry from dried blood spot punches. Genotypes were obtained when a second newborn screening specimen again had a decreased enzyme activity. Additional clinical evaluation was then initiated based on enzyme activity and/or genotype.

RESULTS

Molecular genetic analysis for cases with low enzyme activity revealed 5 newborns with pathogenic alpha-L-iduronidase mutations, 3 newborns with pathogenic iduronate-2-sulfatase mutations, and 1 newborn was a carrier of an arylsulfatase B mutation. Several variants of unknown pathogenic significance were also identified, most likely causing pseudodeficiency.

CONCLUSIONS

The highly robust tandem mass spectrometry-based enzyme assays for MPS-I, MPS-II, and MPS-VI allow for high-throughput newborn screening for these lysosomal storage disorders. Optimized cutoff values combined with second tier testing could largely eliminate false-positive results. Accordingly, newborn screening for these lysosomal storage disorders is possible.

Detecting 22q11.2 Deletion Syndrome in Newborns with Low T Cell Receptor Excision Circles from Severe Combined Immunodeficiency Screening

OBJECTIVE

Based on experiences and results from newborn screening for severe combined immunodeficiency (SCID), we evaluated the occurrence of chromosome 22q11.2 deletion syndrome (22q11.2DS) in newborns with different T cell receptor excision circles (TREC) results and established a second tier genetic test for 22q11.2DS.

STUDY DESIGN

Recalled dried blood spots from 486 newborns with TREC results <90 copies/uL were tested from the SCID newborn screening. Quantitative real-time polymerase chain reaction assay was used to detect the copy number of TBX1 and HIRA genes by simple DNA extraction method. Multiplex ligation dependent probe amplification was used for further confirmation.

RESULTS

Four hundred sixty-eight cases were considered negative because their haploid copy number of TBX1 and HIRA genes was >0.75. Eighteen cases with TBX1 and/or HIRA gene copy number <0.75 were suspected as positive, and 13 cases were further confirmed with 22q11.2DS. Detection rates of 22q11.2DS were 10.7% (6/56) in TREC <30 copies, 6.8% (9/132) in <50 TREC copies, 4.6% (12/260) in <70 TREC copies, and 2.7% (13/486) in <90 TREC copies.

CONCLUSIONS

22q11.2DS detection can be incorporated into the second-tier assay in subjects with low TREC copies in SCID screening. The dried blood spot methods were feasible for 22q11.2DS newborn screening.

Status of newborn screening and follow up investigations for Mucopolysaccharidoses I and II in Taiwan

Background

Mucopolysaccharidoses (MPS) are lysosomal storage diseases in which mutations of genes encoding for lysosomal enzymes cause defects in the degradation of glycosaminoglycans (GAGs). The accumulation of GAGs in lysosomes results in cellular dysfunction and clinical abnormalities. The early initiation of enzyme replacement therapy (ERT) can slow or prevent the development of severe clinical manifestations. MPS I and II newborn screening has been available in Taiwan since August 2015. Infants who failed the recheck at recall were referred to MacKay Memorial Hospital for a detailed confirmatory diagnosis.

Methods

From August 2015 to November 2017, 294,196 and 153,032 infants were screened using tandem mass spectrometry for MPS I and MPS II, respectively. Of these infants, 84 suspected cases (eight for MPS I; 76 for MPS II) were referred for confirmation. Urinary first-line biochemistry examinations were performed first, including urinary GAG quantification, two-dimensional electrophoresis, and tandem mass spectrometry assay for predominant disaccharides derived from GAGs. If the results were positive, a confirmative diagnosis was made according to the results of leukocyte enzymatic assay and molecular DNA analysis. Leukocyte pellets were isolated from EDTA blood and used for fluorescent α-iduronidase (IDUA) or iduronate-2-sulfatase (IDS) enzymatic assay. DNA sequencing analysis was also performed.

Results

Normal IDS and IDUA enzyme activities were found in most of the referred cases except for four who were strongly suspected of having MPS I and three who were strongly suspected of having MPS II. Of these infants, three with novel mutations of the IDS gene (c.817C > T, c.1025A > G, and c.311A > T) and four with two missense mutations of the IDUA gene (C.300-3C > G, c.1874A > C; c.1037 T > G, c.1091C > T) showed significant deficiencies in IDS and IDUA enzyme activities (< 5% of mean normal activity), respectively. Urinary dermatan sulfate and heparan sulfate quantitative analyses by tandem mass spectrometry also demonstrated significant elevations. The prevalence rates of MPS I and MPS II in Taiwan were 1.35 and 1.96 per 100,000 live births, respectively.

Conclusions

The early initiation of ERT for MPS can result in better clinical outcomes. An early confirmatory diagnosis increases the probability of receiving appropriate medical care such as ERT quickly enough to avoid irreversible manifestations. All high risk infants identified in this study so far remain asymptomatic and are presumed to be affected with the attenuated disease variants.

Functional and biological studies of α-galactosidase A variants with uncertain significance from newborn screening in Taiwan

Fabry disease is an X-linked disorder resulted from deficiency of α-galactosidase A (GLA) activity. In Taiwan, a total of 792,247 newborns were screened from 2008 to 2014 in two newborn screening centers, and 13 variants of uncertain significance (VOUS) in the GLA gene were identified. To determine whether these variants were pathogenic or not, functional, biochemical, clinical and pedigree analyses were performed. In vitro functional assay was established through site-directed mutagenesis, and four in silico tools were used to predict pathogenesis. The enzyme activity of dried blood spots and plasma metabolite lyso-Gb3 level from subjects with the variants were measured. Additionally, clinical manifestations were evaluated extensively from the subjects and their relatives. Our results revealed that p.G104V, p.I232T, p.D322H, and p.G360C all exhibited relatively low residual enzyme activities and elevated plasma lyso-Gb3 level. These data strongly suggest that these Fabry mutations may cause classical or later-onset phenotypes. In contrast, neither significantly clinical symptoms nor elevated lyso-Gb3 level was found in cases with p.P60S, p.A108T, p.S304T, p.R356Q, and p.P362T variants, which may be non-pathogenic or milder forms of Fabry variants. More data need to be included for the patients with p.N53D, p.P210S, p.M296L, and p.K391T variants. The established system provides us more information to classify these GLA variants.

Mass Spectrometry but Not Fluorimetry Distinguishes Affected and Pseudodeficiency Patients in Newborn Screening for Pompe Disease

BACKGROUND

Deficiency of the lysosomal enzyme acid α-glucosidase (GAA) causes Pompe disease. Newborn screening for Pompe disease is ongoing, and improved methods for distinguishing affected patients from those with pseudodeficiency, especially in the Asian population, would substantially reduce the number of patient referrals for clinical follow-up.

METHODS

We measured the enzymatic activity of GAA in dried blood spots on newborn screening cards (DBS) using a tandem mass spectrometry (MS/MS) assay. The assay displayed a relatively large analytical range compared to the fluorimetric assay with 4-methylumbelliferyl-α-glucoside. DBS from newborns confirmed to have infantile-onset Pompe disease (IOPD, n = 11) or late-onset Pompe disease (LOPD) (n = 12) and those from patients bearing pseudodeficiency alleles with or without Pompe mutations, or Pompe disease carriers (n = 230) were studied.

RESULTS

With use of the MS/MS GAA assay in DBS, 96% of the pseudodeficiency newborns and all of the Pompe disease carriers were well separated from the IOPD and LOPD newborns. The fluorimetric assay separated <10% of the pseudodeficiencies from the IOPD/LOPD group.

CONCLUSIONS

The relatively large analytical range MS/MS GAA assay but not the fluorimetric assay in DBS provides a robust approach to reduce the number of referrals and should dramatically facilitate newborn screening of Pompe disease.

Lymphocyte Galactocerebrosidase Activity by LC-MS/MS for Post-Newborn Screening Evaluation of Krabbe Disease

BACKGROUND

Deficiency of the lysosomal enzyme galactosylcerebrosidase (GALC) causes Krabbe disease. Newborn screening for Krabbe disease is ongoing, but improved methods for follow-up analysis of screen-positive babies are needed to better advise families and to optimize treatment. We report a new assay for the enzymatic activity of GALC in lymphocytes.

METHODS

T lymphocytes were isolated from venous blood by magnetic bead technology. The assay used a close structural analog of the natural substrate and LC-MS/MS to quantify the amount of product with the aid of a chemically identical internal standard.

RESULTS

The analytical range of the assay (ratio of assay response for the QC high standard to that from all non-enzymatic-dependent processes) was 20-fold greater than that for the conventional radiometric GALC assay. The LC-MS/MS could distinguish cells that were null in GALC from those that contained traces of active enzyme (down to 0.3% of normal). There was a good correlation between the level of residual GALC activity in lymphocytes and the severity of Krabbe disease.

CONCLUSIONS

The new assay can measure small amounts of residual GALC activity in leukocytes with high accuracy compared to previous assays and can contribute, along with genotyping, biomarker analysis, and neurological imaging, a better plan for post-newborn screening follow-up for Krabbe disease.

Very Early Treatment for Infantile-Onset Pompe Disease Contributes to Better Outcomes

OBJECTIVE

To evaluate whether very early treatment in our patients would result in better clinical outcomes and to compare these data with other infantile-onset Pompe disease (IOPD) cohort studies.

METHODS

In this nationwide program, 669,797 newborns were screened for Pompe disease. We diagnosed IOPD in 14 of these newborns, and all were treated and followed in our hospital.

RESULTS

After 2010, the mean age at first enzyme-replacement therapy (ERT) was 11.92 days. Our patients had better biological, physical, and developmental outcomes and lower anti-rh acid α-glucosidase antibodies after 2 years of treatment, even compared with one group that began ERT just 10 days later than our cohort. No patient had a hearing disorder or abnormal vision. The mean age for independent walking was 11.6 ± 1.3 months, the same age as normal children.

CONCLUSIONS

ERT for patients with IOPD should be initiated as early as possible before irreversible damage occurs. Our results indicate that early identification of patients with IOPD allows for the very early initiation of ERT. Starting ERT even a few days earlier may lead to better patient outcomes.

Sulfatide Analysis by Mass Spectrometry for Screening of Metachromatic Leukodystrophy in Dried Blood and Urine Samples

BACKGROUND

Metachromatic leukodystrophy (MLD) is an autosomal recessive disorder caused by deficiency in arylsulfatase A activity, leading to accumulation of sulfatide substrates. Diagnostic and monitoring procedures include demonstration of reduced arylsulfatase A activity in peripheral blood leukocytes or detection of sulfatides in urine. However, the development of a screening test is challenging because of instability of the enzyme in dried blood spots (DBS), the widespread occurrence of pseudodeficiency alleles, and the lack of available urine samples from newborn screening programs.

METHODS

We measured individual sulfatide profiles in DBS and dried urine spots (DUS) from MLD patients with LC-MS/MS to identify markers with the discriminatory power to differentiate affected individuals from controls. We also developed a method for converting all sulfatide molecular species into a single species, allowing quantification in positive-ion mode upon derivatization.

RESULTS

In DBS from MLD patients, we found up to 23.2-fold and 5.1-fold differences in total sulfatide concentrations for early- and late-onset MLD, respectively, compared with controls and pseudodeficiencies. Corresponding DUS revealed up to 164-fold and 78-fold differences for early- and late-onset MLD patient samples compared with controls. The use of sulfatides converted to a single species simplified the analysis and increased detection sensitivity in positive-ion mode, providing a second option for sulfatide analysis.

CONCLUSIONS

This study of sulfatides in DBS and DUS suggests the feasibility of the mass spectrometry method for newborn screening of MLD and sets the stage for a larger-scale newborn screening pilot study.

Globotriaosylsphingosine (lyso-Gb3) might not be a reliable marker for monitoring the long-term therapeutic outcomes of enzyme replacement therapy for late-onset Fabry patients with the Chinese hotspot mutation (IVS4+919G>A)

BACKGROUND

In Taiwan, DNA-based newborn screening showed a surprisingly high incidence (1/875 in males and 1/399 in females) of a cardiac Fabry mutation (IVS4 + 919G > A). However, the natural course, long-term treatment outcomes and suitable biomarkers for monitoring the therapeutic outcomes of these patients are largely unknown.

METHODS

Fabry disease (FD) patients who had received enzyme replacement therapy (ERT) for more than 1 year were enrolled in this study from December 2008 to April 2013. Periodic echocardiography and serum globotriaosylsphingosine (lyso-Gb3) analysis were carried out. Before and after ERT, left ventricular mass index (LVMI) and serum lyso-Gb3 level were compared and the correlation between the change of LVMI and the change of serum lyso-Gb3 were also analyzed.

RESULTS

Thirty-six patients, in four patient groups, were enrolled: (1) 16 males with IVS4 + 919G > A mutation; (2) 7 females with IVS4 + 919G > A mutation; (3) 2 males with classical mutations; and (4) 11 females with classical mutations. The follow-up period was 13-46 months. There were significant LVMI reductions after ERT in all four groups after excluding confounding factors. However, interestingly, serum lyso-Gb3 decreased significantly in the early period after ERT in all groups, but increased gradually after an average of 11.1 months after ERT in late-onset male and female Fabry groups, even when their LVMI still decreased or remained stable. Furthermore, there was no correlation between the change of serum lyso-Gb3 and the change of LVMI in both classical and IVS4 + 919G > A FD patients.

CONCLUSION

Although lyso-Gb3 has a high diagnostic sensitivity in late-onset Fabry patients and has a good response to ERT during the early stages, it might not be a reliable marker for monitoring the long-term therapeutic outcomes of ERT for late-onset Fabry patients with the Chinese hotspot mutation (IVS4 + 919G > A).

Endomyocardial biopsies in patients with left ventricular hypertrophy and a common Chinese later-onset Fabry mutation (IVS4 + 919G > A)

BACKGROUND

In Taiwan, DNA-based newborn screening showed a surprisingly high incidence of a cardiac Fabry mutation (IVS4 + 919G > A). The prevalence of this mutation is too high to be believed that it is a real pathogenic mutation. The purpose of this study is to identify the cardiac pathologic characteristics in patients with left ventricular hypertrophy and this mutation

METHODS AND RESULTS

Endomyocardial biopsies were obtained in 22 patients (Median age: 61, males: 17; females: 5) with left ventricular hypertrophy and the IVS4 + 919G > A mutation; five patients had not received enzyme replacement therapy (ERT) before biopsy, while the other 17 patients had received ERT from 8 months to 51 months. Except for three patients who had received ERT for more than 3 years, all other patients showed significant pathological change and globotriaosylceramide (Gb3) accumulation in their cardiomyocytes. In contrast to classical Fabry patients, no Gb3 accumulation was found in the capillary endothelial cells of any of our patients. Fourteen patients (63.6%) were found to have myofibrillolysis.

CONCLUSIONS

All of the untreated and most of the treated IVS4 + 919G > A patients showed typical pathological changes of Fabry disease in their cardiomyocytes. No endothelial accumulation of Gb3 was found, which is similar to the findings of several previous reports regarding later-onset Fabry disease. This result highly suggests that the IVS4 + 919G > A is a real pathogenic later-onset Fabry mutation.

Clinical observations on enzyme replacement therapy in patients with Fabry disease and the switch from agalsidase beta to agalsidase alfa

BACKGROUND

Fabry disease is an X-linked inherited lysosomal storage disease that can be treated with the enzymes of agalsidase beta (Fabrazyme) and agalsidase alfa (Replagal). Since June 2009, viral contamination of Genzyme's production facility has resulted in a worldwide shortage of agalsidase beta, leading to the switch to agalsidase alfa for patients with Fabry disease in Taiwan.

METHODS

The medical records were retrospectively reviewed for nine male patients with Fabry disease from the start of agalsidase beta treatment until the switch to agalsidase alfa for at least 1 year.

RESULTS

After 12-112 months of enzyme replacement therapy (ERT), decreased plasma globotriaosylsphingosine (lyso-Gb3) was found in five out of seven patients, indicating improvement in disease severity. Among the six patients with available echocardiographic data at baseline and after ERT, all six experienced reductions of left ventricular mass index. Renal function, including microalbuminuria and estimated glomerular filtration rate, showed stability after ERT. Mainz Severity Score Index scores revealed that all nine patients remained stable at 12 months after switching to agalsidase alfa. ERT improved or stabilized cardiac status and stabilized renal function, while reducing plasma lyso-Gb3. ERT was well tolerated, even among the three patients who had hypersensitivity reactions.

CONCLUSION

The switch of ERT from agalsidase beta to agalsidase alfa appears to be safe after 1 year of follow-up for Taiwanese patients with Fabry disease.

Effects of enzyme replacement therapy for cardiac-type Fabry patients with a Chinese hotspot late-onset Fabry mutation (IVS4+919G>A)

OBJECTIVE

Current studies of newborn screening for Fabry disease in Taiwan have revealed a remarkably high prevalence of cardiac-type Fabry disease with a Chinese hotspot late-onset Fabry mutation (IVS4+919G>A).

DESIGN

Retrospective cohort study.

SETTING

Tertiary medical centre.

PARTICIPANTS

21 patients with cardiac-type Fabry disease (15 men and 6 women) as well as 15 patients with classic Fabry disease (4 men and 11 women) treated with biweekly intravenous infusions of agalsidase β (1 mg/kg) or agalsidase α (0.2 mg/kg) for at least 6 months.

OUTCOME MEASURES

These data were collected at the time before enzyme replacement therapy (ERT) began and followed up after ERT for at least 6 months, including patient demographics, medical history, parameter changes of cardiac status and renal functions, plasma globotriaosylsphingosine (lyso-Gb3) and Mainz Severity Score Index.

RESULTS

After 6-39 months of ERT, plasma lyso-Gb3 was found to be reduced in 89% (17/19) and 93% (14/15) of patients with cardiac-type and classic Fabry disease, respectively, which indicated an improvement of disease severity. For patients with cardiac-type Fabry disease, echocardiography revealed the reduction or stabilisation of left ventricular mass index (LVMI), the thicknesses of intraventricular septum (IVS) and left posterior wall (LPW) in 83% (15/18), 83% (15/18) and 67% (12/18) of patients, respectively, as well as 77% (10/13), 73% (11/15) and 60% (9/15) for those with classic type. Most patients showed stable renal function after ERT. There were statistically significant improvements (p<0.05) between the data at baseline and those after ERT for values of plasma lyso-Gb3, LVMI, IVS, LPW and Mainz Severity Score Index. No severe clinical events were reported during the treatment.

CONCLUSIONS

ERT is beneficial and appears to be safe for Taiwanese patients with cardiac-type Fabry disease, as well as for those with the classic type.

Adrenal insufficiency in critically ill emergency department patients: a Taiwan preliminary study

OBJECTIVE

Unrecognized adrenal insufficiency can have serious consequences in critically ill emergency department (ED) patients. This prospective pilot study of adrenal function in patients with severe illness was undertaken to determine the prevalence of adrenal dysfunction and any relation to prior herbal drug use.

METHODS

In a high-volume urban tertiary care ED, adult patients with sepsis or acute myocardial infarction (AMI) were eligible for the study. Over a two-month period, a convenience sample was enrolled by the authors on arrival to the ED. Inclusion criteria were systemic inflammatory response syndrome (SIRS) criteria plus evidence of at least one organ dysfunction or cardiac marker plus electrocardiogram-proven AMI. Exclusion criteria included known corticosteroid use. Serum cortisol was measured on arrival and for those patients with a level of <15 microg/dL (<414 nmol/L), an adrenocorticotropic hormone (ACTH) stimulation test was performed.

RESULTS

Of the 30 enrolled patients, 23 (77%) were suffering from severe sepsis and the other seven (23%) had an AMI. Thirteen of the 30 patients (43%; 95% CI = 25% to 65%) had serum cortisol levels of <15 microg/dL, consistent with adrenal insufficiency, nine with severe sepsis and four with an AMI. Eight (62%; 95% CI = 32% to 86%) of the 13 patients with low cortisol levels reported using herbal medications, while only two (12%; 95% CI = 1% to 36%) of the 17 with normal cortisol levels reported taking herb drugs (p = 0.01). Only two (15%; 95% CI = 2% to 45%) of the patients with low cortisol levels failed their corticotropin stimulation test, suggestive of true adrenocortical insufficiency. Both reported using herbal preparations.

CONCLUSIONS

These results indicate that adrenal dysfunction is common among a group of critically ill patients seen in this Taiwanese ED. Moreover, the use of herbal drugs was high in the patients with low serum cortisols. Further studies are required to both confirm these findings and clarify whether a number of herbal medications contain corticosteroids.

Clinical presentations of elderly patients at emergency departments: a comparison between a medical center and a community hospital

BACKGROUND

The utilization of emergency services is expected to increase in parallel with an increase of the elderly population. This article compares the elderly patient Emergency Department (ED) utilization at a 3500-bed medical center with that of a 600-bed community hospital serviced by the same group of emergency physicians.

METHODS

We retrospectively reviewed all patients over 64 years old who presented to Linkou Chang Gung Memorial Hospital (CGMH) and Keelung CGMH between July 1, 1995 and June 30, 1996 by using the 2 ED's real-time computer logs. Data comparisons included age, gender, mode of arrival, arriving source, triage category, chief complaint, impression, and final disposition.

RESULTS

There were 18,285 patients in the Linkou ED and 8038 in Keelung. Significant differences in arrival mode, arriving source, triage category, disease pattern, and final disposition were observed between the Linkou and Keelung CGMH EDs.

CONCLUSION

Significant differences reflected the different roles between the Linkou and Keelung CGMH EDs. Hospital EDs should be prepared to adapt to meet the needs of the elderly based on their roles in the medical care system, at the elderly population grows in the 21st century.

Differences of disease characteristics between genders in emergency department elderly of a community hospital in Taiwan

BACKGROUND

The purpose of this study was to catalog the chief complaints and diagnoses of elderly patients visiting to a Taiwanese emergency department (ED), and to compare gender differences.

METHODS

ED computer log data of patients 65 years and older, who visited the ED from July 1995 to June 1996, were retrospectively reviewed. The computer log data for each patient was entered prospectively by the doctor providing the ED care. All patient data were separated by gender, and then subdivided into trauma and non-trauma groups for analysis.

RESULTS

There were 8038 elderly patients treated during the study period. The most common male chief complaint was dyspnea, and for females, it was abdominal pain, followed by injuries for both genders. Falls were the most common mechanism of injury for both genders, but they were more common among females (63.2% vs. 46.1%, p < 0.001). Motorbike accidents, however, were 3 times as frequent among males (16.05% vs. 5.45%, p < 0.001). Males presented most commonly with COPD (12.2%), compared to only 4.16% for females (p < 0.001), with urinary retention the second most common diagnosis (5.04% vs. 0.72%, p < 0.001). Females suffered a greater number of urinary tract infections (5.42% vs. 2.03%, p < 0.001), presentations for renal failure (2.98% vs. 1.56% p < 0.001), and diabetes-associated problems (4.58% vs. 2.48%, p < 0.001).

CONCLUSION

Elderly females presented to the ED more frequently with urinary tract and diabetic problems; while their male counterparts presented with complications of COPD, urinary retention, and motorbike accidents.

Rates and causes of emergency department revisits within 72 hours

The purpose of this study was to determine the rates and causes of revisits to the emergency department (ED) of a 3,500-bed referral hospital, to identify areas for improvement, and to generate baseline data for the development of a computerized, automatic monthly audit system. We identified all patients returning within 72 hours of their initial ED visits, from 1 July 1995 to 30 June 1997, and monthly revisit rates were calculated. To determine the reasons for revisits, two independent reviewers examined the charts of revisit cases from 1 July 1996 to 30 June 1997. A one-in-three sampling method was used to select charts. A total of 485 revisit charts were reviewed. The monthly revisit rates ranged from 1.32% to 2.38%, with no particular seasonal or event-specific pattern. Most revisits were attributed to disease factors (79.0%). Those felt to be medical errors only accounted for 7.8% of the revisits but led to a higher hospital admission rate (73.7%) subsequently. By contrast, the overall hospital admission rates for revisit patients (36.5%) and all ED patients (36.2%) were similar. We suggest setting baseline monthly ED revisit rates at 2% for future computer-programmed audit filters. While this study indicates that most revisits are disease-related, further prospective studies are needed to evaluate the most common and serious causes of revisits to see if improvements can be made.

Splenic artery aneurysm rupture in pregnancy--a review and case report

Spontaneous rupture of a splenic artery aneurysm in the third trimester of pregnancy is a catastrophic event associated with a very high fetal and maternal mortality rate. Review of the literature reveals nine reported cases of combined maternal and fetus survival. None were diagnosed prior to rupture and the need for an emergency laparotomy. They survived due to early surgery after fetal distress was noted. We present a 29-year-old female presenting at 33 weeks gestation seeking emergency assistance for vomiting, diarrhea and epigastralgia. During her evaluation and initial management she into shock. At laparotomy a ruptured splenic artery aneurysm was found and ligated. After splenectomy the mother recovered well but unfortunately fetus did not survive.

Preliminary experience with growth factor and porcine graft-young collagenous wettable membrane in the treatment of chronic diabetic ulcer

Chronic ulcers are well-known complication of diabetes mellitus, often compounded by infection. Healing of lesions is problematic in some cases using conventional treatment. We have treated a group of six hospitalized diabetic patients with chronic ulcer by a combined regimen consisting of metabolic control, parenteral antibiotics, growth factor and porcine graft-young collagenous wettable membrane (YCWM) treatment. Five of our uncontrolled group had their ulcers improved at 87 +/- 37.6 hospital days after 45.8 +/- 20.2 days of growth factor and YCWM treatment. In conclusion, growth factor and porcine graft-YCWM therapy may be promising as an alternative choice in treatment of chronic diabetic ulcer.