Utility of an Archival Dried Blood Spot (DBS) Collection from HIV-Infected Individuals with and without Cancer in a Resource-Limited Setting.

The frequency of virus-associated cancers is growing worldwide, especially in resource-limited settings. One of the biggest challenges in cancer research among people living with HIV (PLWH) has been understanding how infection with both HIV and Kaposi sarcoma-associated herpesvirus (KSHV) promotes the pathogenesis of Kaposi sarcoma (KS), the most common cancer among PLWH worldwide and a significant public health problem in regions with high prevalence of HIV such as Sub-Saharan Africa (SSA). The AIDS and Cancer Specimen Resource (ACSR) provides samples for research, including dried blood spots (DBS) that were collected from large clinical epidemiology studies of KSHV and KS in PLWH conducted more than a decade ago in SSA. Here, we validated the quality of DNA derived from DBS samples from SSA studies and provided evidence of quantitative recovery of inflammatory cytokines using these DBS samples through comparison with paired frozen plasma. Significant differences in DNA, protein yields, and inflammatory biomarker levels were also observed between PLWH with/without KS. Establishing the fitness of DBS samples for studies of KS pathogenesis extends the number of projects that can be supported by these ACSR special collections and provides evidence that DBS collection for future KS research is a practical option in resource-limited settings.

Infants with biliary atresia exhibit an altered amino acid profile in their newborn screening.

INTRODUCTION: Biliary atresia (BA) is a rare progressive neonatal cholangiopathy with unknown pathophysiology and time of onset. Newborn Screening (NBS) in Germany is routinely performed in the first days of life to identify rare congenital diseases utilizing dried blood spot (DBS) card analyses. Infants with biliary atresia (BA) are known to have altered amino acid profiles (AAP) at the time point of diagnosis, but it is unclear whether these alterations are present at the time point of NBS. OBJECTIVES: We aimed to analyze amino acid profiles in NBS-DBS of infants with Biliary Atresia. METHODS: Original NBS-DBS cards of 41 infants who were later on diagnosed with BA were retrospectively obtained. NBS-DBS cards from healthy newborns (n = 40) served as controls. In some BA infants (n = 14) a second DBS card was obtained at time of Kasai surgery. AAP in DBS cards were analyzed by targeted metabolomics. RESULTS: DBS metabolomics in the NBS of at that time point seemingly healthy infants later diagnosed with BA revealed significantly higher levels of Methionine (14.6 ± 8.6 µmol/l), Histidine (23.5 ± 50.3 µmol/l), Threonine (123.9 ± 72.8 µmol/l) and Arginine (14.1 ± 11.8 µmol/l) compared to healthy controls (Met: 8.1 ± 2.6 µmol/l, His: 18.6 ± 10.1 µmol/l, Thr: 98.1 ± 34.3 µmol/l, Arg: 9.3 ± 6.6 µmol/l). Methionine, Arginine and Histidine showed a further increase at time point of Kasai procedure. No correlation between amino acid levels and clinical course was observed. CONCLUSION: Our data demonstrate that BA patients exhibit an altered AAP within 72 h after birth, long before the infants become symptomatic. This supports the theory of a prenatal onset of the disease and, thus, the possibility of developing a sensitive and specific NBS. Methionine might be particularly relevant due to its involvement in glutathione metabolism. Further investigation of AAP in BA may help in understanding the underlying pathophysiology.

Diagnostic performance of dried blood spot hepatitis C virus core antigen testing for hepatitis C screening: A systematic review and meta-analysis.

Dried blood spot (DBS) sampling is increasingly used for hepatitis C virus (HCV) screening. HCVcAg testing offers a faster and more streamlined approach to diagnosing HCV infection. We conducted a systematic review and meta-analysis to assess the diagnostic performance of the Abbott ARCHITECT HCV Ag assay for screening active HCV infection using DBS samples. Eight studies (n = 1229) were selected among all published studies available up to October 4, 2024, in different databases with a search strategy registered (PROSPERO: CRD42022363975). The gold standard method was the HCV PCR test. Data were analyzed using the MIDAS module in STATA with a random effects model. Combined diagnostic accuracy measures were as follows: sensitivity 85%, specificity 100%, positive likelihood ratio (PLR) 233.1, negative likelihood ratio (NLR) 0.15, and summary receiver operating characteristic (SROC) 0.99. Likelihood ratios and Fagan's nomogram suggested that the HCVcAg assay with DBS samples can confirm or rule out active HCV infection with over 92% accuracy in high-prevalence settings (≥5%). However, in low-prevalence settings (≤1%), a confirmatory test must be required for positive results. The ability of the test to identify people without HCV infection was high regardless of HCV prevalence, with an error rate of less than 3%. This meta-analysis is subject to limitations, particularly due to the number of included studies and significant heterogeneity among them. HCV screening using the Abbott ARCHITECT HCV Ag assay with DBS samples showed excellent diagnostic performance, but its external validity may be limited when HCV prevalence is low (≤1%).

Ultra high-performance liquid chromatography tandem mass spectrometry: Development and validation of an analytical method for N2-Ethyl-2'-deoxyguanosine in dried blood spot.

In the body, ethanol is metabolized to acetaldehyde by alcohol dehydrogenase and CYP2E1. Acetaldehyde is the main carcinogen that forms DNA adducts, N2-Ethylidene-2'-deoxyguanosine (N2-Ethylidene-dG), which can cause DNA damage and lead to cancer. However, N2-Ethylidene-dG is an unstable form at the nucleoside level and is difficult to measure. So it needs to be reduced using NaBH4 to become N2-Ethyl-2'-deoxyguanosine (N2-Et-dG). This study aims to obtain a selective, sensitive, and validated analytical method to determine N2-Et-dG using ultra-high-performance liquid chromatography-tandem mass spectrometry with allopurinol as the internal standard. The N2-Et-dG analysis was performed using a C18 Acquity® Bridged Ethylene Hybrid column of (1.7 µm, 100 mm × 2.1 mm). The sample matrix used was dried blood spots, and then the DNA sample was extracted using the QIAamp DNA Mini Kit. The optimum analysis conditions were obtained in a combination eluent of 0.1 % acetic acid and methanol (60:40 v/v) with a flow rate of 0.1 mL/min and eluted isocratically for 5 min. Quantification analysis was performed using triple quadrupole mass spectrometry with electrospray ionization in positive mode, with detection at m/z 296.16 > 180.16 for N2-Et-dG and 137.03 > 110.05 for allopurinol, respectively. The validated analytical method follows the 2018 USA Food and Drug Administration guidelines with a linear concentration range of 5-200 ng/mL.

Evaluating the detection of barbiturates in dried blood spots: A comparative analysis using gas chromatography-mass spectrometry, gas chromatography-tandem mass spectrometry, and liquid chromatography-tandem mass spectrometry with different extraction methods.

Rapid and accurate characterization and quantitation of blood barbiturates and their combination drugs are very important for the clinical treatment of acute barbiturate poisoning. A comparison of dried blood spot (DBS) and traditional liquid-liquid extraction (LLE) in the pre-treatment stage, as well as a comparison of gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS/MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) as instrumental analysis methods, revealed differences in the analysis results of barbiturates and their combination drugs under different conditions. Based on these findings, we introduce a DBS-GC-MS/MS method. The developed and validated method showed good selectivity, sensitivity (LOD: 0.1 µg mL-1, LOQ: 0.2 µg mL-1), linearity (R2>0.9992), trueness (<15 %, except for carbamazepine, at 29.4 %), and precision (<15 %). Recovery was also good for most target compounds, but significant matrix effects were evident. Compared with the LLE method, the DBS method has the benefits of easy sample collection, storage, and transport, as well as simple pre-treatment and reduced reagent and energy consumption. Compared to LC-MS/MS, GC-MS/MS requires no switching between positive and negative ion modes and uses the MRM detection mode, meaning that more information about the sample compounds can be obtained in less analysis time. Using actual sample analysis, we have demonstrated the advantages of the DBS-GC-MS/MS method for the qualitative and quantitative analysis of barbiturates and poisoning events due to combinations of these drugs. Comparison of the three instruments and the two treatment methods revealed their analysis characteristics. From the perspective of practical application, the broad practical value and advantages of DBS should be embraced in more applications, and future analytical laboratory development should continue to recognize GC-MS/MS as a useful supplement to LC-MS/MS.

Diagnostic Value of Menstrual Blood Lipidomics in Endometriosis: A Pilot Study.

Endometriosis is a prevalent chronic inflammatory disease characterized by a considerable delay between initial symptoms and diagnosis through surgery. The pressing need for a timely, non-invasive diagnostic solution underscores the focus of current research efforts. This study examines the diagnostic potential of the menstrual blood lipidome. The lipid profile of 39 samples (23 women with endometriosis and 16 patients in a control group) was acquired using reverse-phase high-performance liquid chromatography-mass spectrometry with LipidMatch processing and identification. Profiles were normalized based on total ion counts. Significant differences in lipids were determined using the Mann-Whitney test. Lipids for the diagnostic model, based on logistic regression, were selected using a combination of variance importance projection filters and Akaike information criteria. Levels of ceramides, sphingomyelins, cardiolipins, triacylglycerols, acyl- and alkenyl-phosphatidylethanolamines, and alkenyl-phosphatidylcholines increased, while acyl- and alkyl-phosphatidylcholines decreased in cases of endometriosis. Plasmenylphosphatidylethanolamine PE P-16:0/18:1 and cardiolipin CL 16:0_18:0_22:5_22:6 serve as marker lipids in the diagnostic model, exhibiting a sensitivity of 81% and specificity of 85%. The diagnostic approach based on dried spots of menstrual blood holds promise as an alternative to traditional non-invasive methods for endometriosis screening.

Detection of transgenes in equine dried blood spots using digital PCR and qPCR for gene doping control.

Due to the ease of collection, transport and storage, the use of dried blood spots (DBS) offers an attractive alternative matrix for detection of the abuse of gene therapy, otherwise known as gene doping. This study evaluated the recovery, extraction efficiency and resulting detection capability of DNA from DBS by evaluating different target types, DNA extraction kits, the number of punches and blood tube preservatives. The long-term storage stability of low-copy-number transgene targets in DBS was not assessed in this study but would be noteworthy to investigate further. DNA was quantified using two detection methods: qPCR and digital PCR (dPCR). Using six punches with the Qiagen Investigator kit gave the best overall DNA yield compared with other extraction methods. Including three punches, however, gave better DNA extraction efficiency. Reference material could be detected using qPCR and dPCR in DBS spiked with 5000 copies/mL of blood (approximately 15 copies per 3 mm of punch). The optimal DNA extraction protocol was used on DBS samples from a custom recombinant adeno-associated virus administration study and showed successful detection of vector targets in DBS samples.

Unraveling the metabolomic architecture of autism in a large Danish population-based cohort.

BACKGROUND: The prevalence of autism in Denmark has been increasing, reaching 1.65% among 10-year-old children, and similar trends are seen elsewhere. Although there are several factors associated with autism, including genetic, environmental, and prenatal factors, the molecular etiology of autism is largely unknown. Here, we use untargeted metabolomics to characterize the neonatal metabolome from dried blood spots collected shortly after birth. METHODS: We analyze the metabolomic profiles of a subset of a large Danish population-based cohort (iPSYCH2015) consisting of over 1400 newborns, who later are diagnosed with autism and matching controls and in two Swedish population-based cohorts comprising over 7000 adult participants. Mass spectrometry analysis was performed by a timsTOF Pro operated in QTOF mode, using data-dependent acquisition. By applying an untargeted metabolomics approach, we could reproducibly measure over 800 metabolite features. RESULTS: We detected underlying molecular perturbations across several metabolite classes that precede autism. In particular, the cyclic dipeptide cyclo-leucine-proline (FDR-adjusted p = 0.003) and the carnitine-related 5-aminovaleric acid betaine (5-AVAB) (FDR-adjusted p = 0.03), were associated with an increased probability for autism, independently of known prenatal and genetic risk factors. Analysis of genetic and dietary data in adults revealed that 5-AVAB was associated with increased habitual dietary intake of dairy (FDR-adjusted p < 0.05) and with variants near SLC22A4 and SLC22A5 (p < 5.0e - 8), coding for a transmembrane carnitine transporter protein involved in controlling intracellular carnitine levels. CONCLUSIONS: Cyclo-leucine-proline and 5-AVAB are associated with future diagnosis of autism in Danish neonates, both representing novel early biomarkers for autism. 5-AVAB is potentially modifiable and may influence carnitine homeostasis.

Development and validation of UPLC-MS/MS method for 5-Fluorouracil quantification in dried blood spot.

5-Fluorouracil is an antimetabolite drug indicated for cancer treatment. Therapeutic drug monitoring of 5-Fluorouracil is necessary because 5-Fluorouracil has narrow therapeutic window and its concentration in blood is affected by individual conditions, like gene polymorphisms. Dried Blood Spot (DBS) is one of the biosampling methods used for therapeutic drug monitoring. Asides from reducing patients' discomfort, the use of DBS can increase 5-Fluorouracil stability by stopping the enzymes activity in blood. Therefore, this research developed a method to monitor 5-Fluorouracil levels in DBS using ultra-high performance liquid chromatography-tandem mass spectrometry. Sample preparation was carried out by extracting DBS using 2-Propanol: ethyl acetate (16:84). Reconstituted samples were analyzed using ultra high performance liquid chromatography equipped with Acquity® UPLC BEH C18 column (2.1 × 100 mm; 1.7 µm). The ionization process was carried out in negative electrospray ionization mode. Multiple Reaction Monitoring (MRM) values were set at m/z 128.97 > 41.82 for 5-Fluorouracil and 168.97 > 57.88 for propylthiouracil as the internal standard. Optimum analytical conditions were obtained with acetonitrile-ammonium acetate 1 mM (95:5) as mobile phase, flow rate of 0.15 mL/min, and column temperature of 40 °C. The lowest level of quantification obtained from this method was 0.1 µg/mL with a calibration curve range of 0.1 µg/mL-60 µg/mL. This method was proven to be valid according to the requirements set by the US Food and Drug Administration and the European Medicines Agency.

Therapeutic drug monitoring of osimertinib in EGFR mutant non-small cell lung cancer by dried blood spot and plasma collection: A pilot study.

AIMS: Therapeutic drug monitoring (TDM) has led to significant improvements in individualized medical care, although its implementation in oncology has been limited to date. Tyrosine kinase inhibitors (TKIs) are a group of therapies for which TDM has been suggested. Osimertinib is one such therapy used in the treatment of epidermal growth factor receptor (EGFR) mutation-driven lung cancer. Herein, we describe a prospective pilot study involving 21 patients on osimertinib primarily as a preliminary evaluation of drug levels in a real-world setting. METHODS: Concentrations of the drug and its primary metabolites were measured with a validated liquid chromatography-mass spectrometry (LC-MS) assay across serial timepoints. As part of this study, inter-individual variability by dose and ethnicity as well as intra-individual variability across timepoints are explored. Furthermore, we attempted to validate dried blood spot (DBS)-based quantitation as an accurate alternative to plasma quantitation. RESULTS: Successful quantitation of osimertinib and primary metabolites was achieved for our subjects. Compound plasma levels were highly correlated to DBS levels. There was no significant difference in concentrations with ethnicity or dosing or intra-individual variability across timepoints. CONCLUSIONS: As such, we demonstrate that TDM for osimertinib is practical for future trials. We also validated the use of DBS as an alternative to conventional quantitation for exploration of TDM for osimertinib in larger trials and for other targeted therapies.

Temporal tracking of cysteine 34 oxidation of plasma albumin as a biomarker of muscle damage following a bout of eccentric exercise.

PURPOSE: Exercise-induced muscle damage (EIMD) results in the generation of reactive oxygen species (ROS), but little is known about the temporal profile of change in ROS post-EIMD and how ROS levels relate to the onset of and recovery from EIMD. Our primary aim was to examine the effect of EIMD on the pattern of change in the blood level of thiol-oxidised albumin, a marker of oxidative stress. METHODS: Seven male participants were subjected on separate days to eccentric muscle contraction to cause EIMD or a no-exercise condition. After each session, the participants collected daily dried blood spots to measure thiol-oxidised albumin and returned to the laboratory every 2 days for the assessment of indirect markers of EIMD, namely maximal voluntary contraction (MVC), delayed onset muscle soreness (DOMS), creatine kinase (CK), and myoglobin. RESULTS: Eccentric exercise resulted in a significant decrease in MVC and increase in DOMS, CK, myoglobin, and thiol-oxidised albumin with the latter reaching above baseline level within 24-48 h post-exercise. All the markers of EIMD returned to baseline level within 6 days post-exercise, but not the level of thiol-oxidised albumin which remained elevated for 10 days after exercise. There was a moderate correlation between changes in thiol-oxidised albumin and DOMS, but no significant relationship between any other markers of muscle damage. CONCLUSION: The levels of thiol-oxidised albumin increase in response to EIMD and remain elevated for several days post-exercise. The temporal pattern of change in the level of thiol-oxidised albumin suggests that this may be a useful biomarker of muscle repair post-EIMD.

Acceptability and Feasibility of the Plasma Separation Card for an Integrated Model of Care for HBV and HCV Screening Among People Attending HIV Clinics in Cameroon and Uganda.

BACKGROUND: Sub-Saharan African countries have a high burden of viral hepatitis and poor access to screening and care. The aim of this study was to evaluate the feasibility and acceptability of using the plasma separation card (PSC) for viral hepatitis B and C screening among people living with HIV (PLHIV) in Cameroon and Uganda. METHODS: This is a cross-sectional study carried out between 05/2021 and 03/2023 including 192 PLHIV in Cameroon (n = 104) and Uganda (n = 88). Basic sociodemographic variables and whole blood samples were collected. Adequate filling with blood of PSCs was used to determine feasibility together with participant responses to questions on acceptability. A logistic regression model was carried out to assess the relationship between PSC acceptability and factors of interest. RESULTS: 70% of participants reported PSC as an acceptable viral hepatitis screening tool, and it was significantly more accepted in Uganda than Cameroon (100% vs. 43.2%, p < 0.001). Similarly, 75% of PSCs had at least one spot sample filled and were viable for analysis, 99% were correctly filled in Uganda and 53.4% in Cameroon. Reported ease of method performance (aOR: 24.77 95% CI 2.97-206.42, p = 0.003) and reduced collection time (aOR: 3.73 95% CI 1.26-11.04, p = 0.017) were associated with greater odds of PSC acceptance. HBsAg + and anti-HCV + prevalence were 11.1% and 1.0%, respectively. CONCLUSIONS: In spite of country differences, overall, the PSC was reported as a feasible and acceptable viral hepatitis testing method. Acceptability and feasibility of the method must be explored in heterogeneous target communities and qualitative research to better understand country-specific barriers and facilitators should be carried out.

Determination of intracellular tenofovir-diphosphate and emtricitabine-triphosphate concentrations in dried blood spots for pre-exposure prophylaxis adherence.

OBJECTIVES: We measured the intracellular concentrations of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) in dried blood spots (DBS) for pre-exposure prophylaxis (PrEP) adherence using sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: A total of 191 DBS were obtained from 85 participants who were receiving tenofovir disoproxil fumarate (TDF; 300 mg) and emtricitabine (FTC; 200 mg) as PrEP at the Sexual Health Clinic, National Center for Global Health and Medicine, Tokyo, Japan. DBS punch (3 mm) added to 25 µL of 50% methanol and 400 µL of internal standard solution was used for solid phase extraction. Chromatographic separation was achieved on an Atlantis Premier BEH C18 AX Column (50 mm × 2.1 mm i.d.; particle size 1.7 µm) using gradient elution (flow rate: 0.6 mL/min); injection volume: 7 µL and run time: 5.5 min. Calibration curves for the two drugs were linear in the range 0.05-12.5 ng/punch. RESULTS: We determined the intracellular TFV-DP and FTC-TP concentrations in 191 DBS obtained from 85 patients administered with TDF and FTC as PrEP. The analytical performance data (calibration curve and QC samples) for all the analytical runs met the acceptance criteria. Intracellular concentrations of TFV-DP and FTC-TP in the DBS remained stable for at least 24 h after oral administration. CONCLUSIONS: A multiplex LC-MS/MS method was successfully developed for DBS, which can be useful for monitoring the levels of TFV-DP and FTC-TP in individuals receiving PrEP.

Maternal pre-pregnancy and prenatal penicillin, neonatal inflammation and growth factors are associated to ADHD in the offspring.

Background: The etiology for Attention Deficit Hyperactivity Disorder (ADHD) is generally unknown, but both genetics, biology and environment have been shown to increase the risk. The purpose of this study was to explore the prenatal risk factors, especially maternal antibiotics consumed before and during pregnancy, for the offspring for later being diagnosed with ADHD, and to find associations with neonatal biomarkers. Methods: We included new-borns from the CODIBINE study, 465 children were ADHD cases and 10 954 children were controls. Ten biomarkers reflecting inflammation, neonatal stress, and/or neurologic development or damage were measured in dried blood spot samples drawn 2-3 days after birth. Maternal and child prescriptions of medication, birth data, and disorder codes were included in the statistical analyses. Results: We found that maternal penicillin prescriptions until 2 years before birth increased the risk for offspring ADHD. The risk was higher with multiple prescriptions, both before and during pregnancy. Cases with maternal penicillin prescriptions had lower neonatal levels of epidermal growth factor (EGF) and soluble Tumor Necrosis Factor Receptor I (sTNF RI). Maternal prescriptions for psychotropic medication have, as expected, the highest correlation to offspring ADHD, but we found no differences in biomarkers in this group. Conclusion: The fact that the offspring risk for ADHD was increased also with pre-pregnancy prescriptions of penicillin, indicates that it is not the penicillin that is the direct cause of the adverse effects. The significant differences in biomarkers strengthens the findings, as these could not be associated to other factors than maternal penicillin and offspring ADHD.

Congenital Cytomegalovirus Testing Outcomes From the ValEAR Trial.

OBJECTIVE: To determine the positivity rate of congenital cytomegalovirus (cCMV) testing among universal, hearing-targeted CMV testing (HT-cCMV) and delayed targeted dried blood spot (DBS) testing newborn screening programs, and to examine the characteristics of successful HT-cCMV testing programs. STUDY DESIGN: Prospective survey of birth hospitals performing early CMV testing. SETTING: Multiple institutions. METHODS: Birth hospitals participating in the National Institutes of Health ValEAR clinical trial were surveyed to determine the rates of cCMV positivity associated with 3 different testing approaches: universal testing, HT-cCMV, and DBS testing. A mixed methods model was created to determine associations between successful HT-cCMV screening and specific screening protocols. RESULTS: Eighty-two birth hospitals were surveyed from February 2019 to December 2021. Seven thousand six hundred seventy infants underwent universal screening, 9017 infants HT-cCMV and 535 infants delayed DBS testing. The rates of cCMV positivity were 0.5%, 1.5%, and 7.3%, respectively. The positivity rate for universal CMV screening was less during the COVID-19 pandemic than that reported prior to the pandemic. There were no statistically significant drops in positivity for any approach during the pandemic. For HT-cCMV testing, unique order sets and rigorous posttesting protocols were associated with successful screening programs. CONCLUSION: Rates of cCMV positivity differed among the 3 approaches. The rates are comparable to cohort studies reported in the literature. Universal CMV prevalence decreased during the pandemic but not significantly. Institutions with specific order set for CMV testing where the primary care physician orders the test and the nurse facilitates the testing process exhibited higher rates of HT-cCMV testing.

Estimation of the reference values and decision limits for growth hormone in newborns using dried blood spots.

OBJECTIVES: Severe deficiency of growth hormone (GHD) of the newborn is a rare but potentially life-threatening disease. GH measured during the first week of life, using dried blood spots (DBS), may offer several advantages. Aim of the study was to estimate the reference values for GH in newborns by a new analytical method using DBS. METHODS: Using a new developed analytical method, GH was estimated from DBS of 1,036 healthy newborns attending the Neonatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of Milan in the period July-October 2021. Reference values for GH deficiency were estimated by the Harrell-Davis bootstrap method, with 90 %CI calculated by the bias-corrected and accelerated bootstrap method. RESULTS: All GH measurements required 33 analytical sessions (8 months) with a CV% for calibration curve slopes equal to 6.9 %. Intermediate precision evaluated by measurement of low (3 µg/L) and high (10 µg/L) quality controls was, respectively, 14 and 6.5 %. GH reference values, estimated at percentiles 1.0st, 2.5th and 5.0th, and their 90 %CI, were, respectively, 4.5 µg/L (90 %CI 3.8-5.1), 5.9 µg/L (90 %CI 5.4-6.4) and 7.0 µg/L (90 %CI 6.7-7.3). GH levels were not associated with sex, standard deviation scores, birth weight, gestational age, type of delivery or mother's variables (age, smoking habit, gestational diabetes). CONCLUSIONS: Validation data suggest that this method can be used to measured GH in newborns using DBS. The reference values estimated in this study are in accordance with previous published works using ELISA and may help confirming the clinical suspicion of neonatal GHD.

One-step NGS molecular analysis of the CFTR gene on newborn dried blood spots gives a higher diagnostic sensitivity in affected and carrier subjects: A pilot study.

BACKGROUND: Cystic fibrosis is the most common hereditary recessive disease with an incidence of about 1:2500/3000. It has long been known that the disease is caused by deleterious mutations in the CFTR gene. Conventionally, the disease is diagnosed in several phases. The analysis of all the possible disease-causing molecular alterations is time consuming and may not lead to a definitive diagnosis in several cases. Consequently, we propose, in this paper, a rapid sequencing method that, in a single procedural asset, reveals the presence of small mutations and also the copy number variants (CNVs) from the DNA extracted from the Guthrie Spot. MATERIALS AND METHODS: We first sequenced 30 blood spots, then we validated the method on 100 spots that underwent both traditional analyses and this complete NGS sequencing, and lastly, we tested the strategy on patients who normally do not reach the molecular sequencing step because of low level of Immune-Reactive Trypsinogen. RESULTS: Using this procedure, we identified 97 variants in the CFTR gene of our samples and 6 CNVs. Notably, the significant data were obtained in the group of patients with borderline or negative IRT who routinely would not undergo molecular testing. We also identified 6 carriers of "disease-causing" variants. CONCLUSION: This method is very robust. Indeed, there was a 100% concordance with Sanger sequencing validation, and 6 mutation carriers were identified who normally escaped molecular testing with actual conventional procedure. There were also 3 duplications of almost the entire gene in heterozygosity, which were not seen with traditional methods. Being quick and easy to perform, we suggest that complete sequencing of the CFTR gene, as in this study be considered for all newborns.

Metabolomic analysis for asymptomatic hyperuricemia and gout based on a combination of dried blood spot sampling and mass spectrometry technology.

BACKGROUND: Gout is the most common inflammatory arthritis and closely related to metabolic syndrome, leading to excruciating pain and the decline in quality of patients' life. However, the pathogenesis of gout is still unclear, and novel biomarkers are demanded for the early prediction and diagnosis of gout. OBJECTIVE: This study aimed at profiling the dysregulated metabolic pathways in asymptomatic hyperuricemia (AHU) and gout and elucidating the associations between AHU, gout and metabolomics, which may aid in performing gout screening. METHODS: A total of 300 participants, including 114 healthy controls, 92 patients with AHU, and 94 patients with gout, were analyzed by using a combination of dried blood spot (DBS) sampling and mass spectrometry (MS) technology. Multiple algorithms were applied to characterize altered metabolic profiles in AHU and gout. The mainly altered metabolites were identified by random forest analysis. RESULTS: There were significant differences in AHU and gout compared with control group. The altered metabolites were involved in oxidation of fatty acids, carnitine synthesis, urea cycle, and amino acid metabolism in AHU and gout. Random forest classification of 16 metabolites yielded 3 important features to distinguish gout from AHU. CONCLUSIONS: Distinct metabolomic signatures were observed in AHU and gout. The selected metabolites may have the potential to improve the early detection of gout.

New Perspectives in Dried Blood Spot Biomarkers for Lysosomal Storage Diseases.

Dried blood spots (DBSs) biomarkers are convenient for monitoring for specific lysosomal storage diseases (LSDs), but they could have relevance for other LSDs. To determine the specificity and utility of glycosphingolipidoses biomarkers against other LSDs, we applied a multiplexed lipid liquid chromatography tandem mass spectrometry assay to a DBS cohort of healthy controls (n = 10) and Gaucher (n = 4), Fabry (n = 10), Pompe (n = 2), mucopolysaccharidosis types I-VI (n = 52), and Niemann-Pick disease type C (NPC) (n = 5) patients. We observed no complete disease specificity for any of the markers tested. However, comparison among the different LSDs highlighted new applications and perspectives of the existing biomarkers. We observed elevations in glucosylceramide isoforms in the NPC and Gaucher patients relative to the controls. In NPC, there was a greater proportion of C24 isoforms, giving a specificity of 96-97% for NPC, higher than 92% for the NPC biomarker N-palmitoyl-O-phosphocholineserine ratio to lyso-sphingomyelin. We also observed significantly elevated levels of lyso-dihexosylceramide in Gaucher and Fabry disease as well as elevated lyso-globotriaosylceramide (Lyso-Gb3) in Gaucher disease and the neuronopathic forms of Mucopolysaccharidoses. In conclusion, DBS glucosylceramide isoform profiling has increased the specificity for the detection of NPC, thereby improving diagnostic accuracy. Low levels of lyso-lipids can be observed in other LSDs, which may have implications in their disease pathogenesis.

LC-MS/MS Method for the Quantification of PARP Inhibitors Olaparib, Rucaparib and Niraparib in Human Plasma and Dried Blood Spot: Development, Validation and Clinical Validation for Therapeutic Drug Monitoring.

Poly (ADP-ribose) polymerase inhibitors (PARPis) are becoming increasingly meaningful in oncology, and their therapeutic drug monitoring (TDM) might be beneficial for patients. Several bioanalytical methods have been reported for PARPis quantification in human plasma, but advantages might be obtained using dried blood spot (DBS) as a sampling technique. Our aim was to develop and validate a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for olaparib, rucaparib, and niraparib quantification in both human plasma and DBS matrices. Additionally, we aimed to assess the correlation between the drug concentrations measured in these two matrices. DBS from patients was obtained using Hemaxis DB10 for volumetric sampling. Analytes were separated on a Cortecs-T3 column and detected with electrospray ionization (ESI)-MS in positive ionization mode. Validation was performed according to the latest regulatory guidelines, in the range (ng/mL) 140-7000 for olaparib, 100-5000 for rucaparib, and 60-3000 for niraparib, within the hematocrit (Hct) range 29-45%. The Passing-Bablok and Bland-Altman statistical analyses revealed a strong correlation between plasma and DBS for olaparib and niraparib. However, due to the limited amount of data, it was challenging to establish a robust regression analysis for rucaparib. To ensure a more reliable assessment, additional samples are required. The DBS-to-plasma ratio was used as a conversion factor (CF) without considering any patient-related hematological parameters. These results provide a solid basis for the feasibility of PARPis TDM using both plasma and DBS matrices.