BackgroundFibroblast growth factor 23 (FGF23) is a bone-derived phosphaturic hormone that is essential for phosphate homeostasis. Elevated FGF23 levels underlie FGF23-related hypophosphatemic rickets and tumor-induced osteomalacia. Despite its clinical importance, population-based reference intervals (RIs) for intact FGF23 using the widely deployed LIAISON XL automated chemiluminescent immunoassay platform (DiaSorin) are lacking for East Asian populations.MethodsWe established method-specific RIs for intact FGF23 (iFGF23) in 386 healthy Korean adults (193 males and 193 females; age, 20–79 years) following the Clinical and Laboratory Standards Institute EP28-A3c guidelines. After the Box–Cox transformation and Horn’s outlier detection, the RIs were derived using nonparametric methods (2.5th–97.5th percentiles). The necessity for partitioning was assessed using the Harris–Boyd method. Associations between iFGF23 levels and demographic, anthropometric, and biochemical parameters were examined using Pearson’s correlation coefficients.ResultsThe overall nonparametric RI was 28.04–100.33 pg/mL (90% CI: 25.77–31.91 to 96.29–109.20). Age emerged as the primary determinant requiring partitioning, with young adults (20–29 years) exhibiting significantly lower concentrations than older adults (≥30 years): 25.73–78.76 versus 32.01–107.00 pg/mL. A sex-stratified analysis confirmed that this age effect persisted independently in both males and females. Although males had higher median iFGF23 than females (65.03 vs. 51.98 pg/mL, p < 0.001), Harris–Boyd analysis did not support sex-based partitioning (z = 5.17, z* = 5.38). Intact FGF23 was significantly correlated with age (r = 0.278), estimated glomerular filtration rate (r = –0.254), and alkaline phosphatase (r = 0.143; all p ≤ 0.005), but not with traditional mineral metabolism parameters (phosphate, calcium, parathyroid hormone, and 25-hydroxyvitamin D).ConclusionsThis study provides the first population- and method-specific RIs for intact FGF23 in an East Asian population and establishes critical age-stratified benchmarks for clinical interpretation. The distinct RI in young adults underscores the necessity of age-appropriate reference standards for diagnosing and monitoring phosphate homeostasis disorders. These findings highlight the importance of population-specific reference data in the absence of assay harmonization.

Background: Pancreatic ductal adenocarcinoma (PDAC) in patients with diabetes mellitus (DM) represents a clinically heterogeneous subgroup, yet biomarkers that reflect diabetes-associated tumor biology and chemotherapy response remain limited. In particular, the influence of diabetes duration on treatment resistance in PDAC is poorly understood. Methods: We performed an integrated translational analysis combining reanalysis of public single-cell RNA sequencing (scRNA-seq) datasets, clinical serum biomarker profiling, and functional validation using pancreatic cancer cell lines and patient-derived organoids. Circulating REG4 concentrations were measured in independent PDAC cohorts and correlated with diabetes duration, overall survival, and response to FOLFIRINOX. Functional relevance was assessed under diabetes-mimicking hyperglycemic conditions. Results: Single-cell transcriptomic analysis demonstrated enrichment of REG4-expressing tumor cells within the classical PDAC subtype specifically in diabetic patients. Clinically, circulating REG4 concentrations were significantly elevated in PDAC patients with long-standing diabetes, and high REG4 levels were associated with poor overall survival and resistance to FOLFIRINOX exclusively in this subgroup. In contrast, no prognostic association was observed in non-diabetic or new-onset diabetic patients. In patient-derived organoids and pancreatic cancer cell lines, chronic glucose exposure induced REG4 expression, activation of WNT/β-catenin signaling, suppression of apoptotic pathways, and increased resistance to FOLFIRINOX, recapitulating key clinical features of long-standing diabetes-associated PDAC. Conclusions: These findings suggest REG4 as a candidate diabetes duration–dependent prognostic and predictive biomarker in pancreatic cancer, warranting validation in larger prospective cohorts. By linking metabolic context to chemotherapy resistance through REG4-associated signaling, this study provides a translational framework for patient stratification and treatment optimization in diabetes-associated PDAC.

Background: Sepsis is a life-threatening condition, requiring timely diagnosis and reliable biomarkers for effective management. Lysophosphatidylcholine (LPC) has emerged as a promising biomarker; however, conventional quantification methods, such as liquid chromatography- tandem mass spectrometry (LC-MS/MS), are time-consuming and resource-intensive. We developed and validated an automated rapid testing platform based on enzymatic spectrophotometry for serum LPC quantification. Methods: Serum LPC was quantified using an automated rapid testing platform based on enzymatic hydrogen peroxide generation, detected colorimetrically with the chromogen DA-67. Analytical accuracy was evaluated through method comparison with ultraviolet-visible spectrophotometry (N=35 samples) and an LC-MS/MS (N=120 samples). Participants were classified into sepsis and septic shock (N=35), systemic inflammatory response syndrome (SIRS, N=10), and healthy controls (N=75). Statistical analyses included logistic regression, ROC analysis, and Kaplan-Meier survival analysis. Results: The automated rapid testing platform reflected LPC concentration-dependent absorbance changes and differentiated clinical groups. Serum LPC concentrations were significantly lower in patients with sepsis or septic shock than in healthy controls and patients with SIRS (all P <0.05). We observed strong concordance with LC-MS/MS data (r=0.99) and significant correlations with C-reactive protein concentrations and white blood cell counts. Low LPC concentrations were independently associated with 90-day mortality. Conclusions: Our platform enables rapid and accurate LPC measurements with minimal sample requirements, facilitating diagnosis and risk stratification and paving the way for more individualized and timely care for patients with sepsis.

The combination of epirubicin, cisplatin, and 5-fluorouracil (ECF) is widely used for gastric cancer treatment. However, cancer cells can acquire chemoresistance over multiple treatment cycles, leading to recurrence. This study aimed to investigate a novel biomarker for predicting ECF resistance and its biological roles in gastric cancer. ECF-resistant (ECF-R) gastric cancer cell lines were established through stepwise ECF treatment. Transcriptome analysis was performed to identify resistance-related genes, which were validated in tumor organoids and in vivo models. Additionally, gastric cancer patient tumor tissues were analyzed for clinical relevance. Transcriptome analysis revealed that NINJURIN2 and CD44 were highly expressed in ECF-R cells but rarely expressed in normal gastric tissues. NINJURIN2 inhibition significantly increased chemosensitivity to ECF in vitro and in vivo. Liquid chromatography–tandem mass spectrometry identified periostin as a binding partner of NINJURIN2, mediating chemoresistance. Furthermore, VAV2 phosphorylation was markedly upregulated in ECF-R cells but was inhibited by NINJURIN2 knockdown. Clinical analysis showed that high NINJURIN2 expression correlated with poor survival outcomes in gastric cancer patients. Our findings suggest that NINJURIN2 can be used as a novel biomarker for chemoresistant gastric cancer patients and that inhibiting NINJURIN2 along with standard chemotherapy could prevent chemoresistance-associated relapse in gastric cancer.

Hemolysis is one of the important preanalytical factor that can influence the laboratory test results. As arterial blood gas analysis (ABGA) is performed with whole blood, it is difficult to visually check hemolysis state of the specimen, and even blood gas analyzers cannot detect hemolysis. However, there is not enough consensus or guideline on which parameters are influenced with hemolysis. This study was aimed to identify the influence of hemolysis on ABGA results and develop a predictive model for hemolysis interference. A total of 142 residual arterial blood specimens were collected from a teritary hospital in South Korea. Samples were aliquoted into three groups for mechanical hemolysis. Hemolysis was induced via 16, 22, and 26 Gauge needles and measured using the Profile pHOx Ultra Blood Gas Analyzer (Nova Biomedical, Waltham, MA, USA). The remaining blood was centrifuged, and hemolysis index was identified using plasma. The differences among groups were evaluated by one-way analysis of variance (ANOVA). In addition, the test results were divided into two sets: the training set and the test set. R studio (version 4.3.1) was used for the statistical analysis and the development of the predictive model. To select the optimal combination of parameters, we employed the backward elimination method. Among the parameters, pH and K values increased whereas pCO2, Na, Ca2+, and HCO3- values decreased. Values of pCO2, Hb, K, and Ca2+ increased as the degree of hemolysis increased with % biases exceeding the desirable bias. When the predictive model developed with training set was tested, the model that included pCO2, Hb, K, Cl, Ca2+, Lac, and tCO2 as variables demonstrated the top-flight performance. This model achieved the highest area under the curve (AUC) among all tested combinations (AUC=0.905). It exhibited a sensitivity of 89.6% and a specificity of 92.1%. This study confirms that hemolysis influences the values of pH, pCO2, and K significantly. Furthermore, a predictive model was validated for detection of hemolysis interference in whole blood specimens used for ABGA. Therefore, the predictive model to detect spurious hemolysis should be adopted in ABGA instruments in clinical laboratories and POCT environments to reduce the analytical errors caused by hemolysis.

OBJECTIVES:Identifying the potential sources of bias in the direct measurement of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) is important. In this study, we aimed to investigate the effect of remnant cholesterol on LDL-C and HDL-C levels measured using homogenous methods. METHODS:We obtained 41 commutable frozen serum samples and measured LDL-C and HDL-C levels. Eight measurement systems were used, and the degree of bias was obtained by comparing with the values obtained using the reference methods. Correlations among remnant cholesterol/LDL-C, remnant cholesterol/HDL-C, and bias were analyzed using Spearman's analysis. RESULTS:In all eight systems, samples with a positive bias >4 % had lower LDL-C levels and higher remnant cholesterol levels, as measured by the reference methods, compared to those with a bias ≤4 %. A significant correlation between remnant cholesterol/LDL-C and a positive bias of LDL-C was observed in six of the eight systems evaluated. For HDL-C bias, three systems showed a positive correlation, and three systems showed a negative correlation. In some systems, LDL-C bias was higher in samples with remnant cholesterol/LDL-C ≥0.25 than in those with remnant cholesterol/LDL-C <0.25. CONCLUSIONS:Remnant cholesterol has a potential effect on direct LDL-C and HDL-C measurements, which has been observed when several measurement systems are used. For these systems, manufacturers should improve the methods to reduce the interference of remnant cholesterol.

BackgroundFor best efficacy, vaccines must provide long-lasting immunity. To measure longevity, memory from B and T cells are surrogate endpoints for vaccine efficacy. When antibodies are insufficient for protection, the immune response must rely on T cells. The magnitude and differentiation of effective, durable immune responses depend on antigen-specific precursor frequencies. However, development of vaccines that induce durable T-cell responses for cancer treatment has remained elusive.MethodsTo address long-lasting immunity, patients with HER2+ (human epidermal growth factor receptor 2) advanced stage cancer received HER2/neu targeted vaccines. Interferon-gamma (IFN-γ) enzyme-linked immunosorbent spot measuring HER2/neu IFN-γ T cells were analyzed from 86 patients from three time points: baseline, 1 month after vaccine series, and long-term follow-up at 1 year, following one in vitro stimulation. The baseline and 1-month post-vaccine series responses were correlated with immunity at long-term follow-up by logistic regression. Immunity was modeled by non-linear functions using generalized additive models.ResultsAntigen-specific T-cell responses at baseline were associated with a 0.33-log increase in response at long-term follow-up, 95% CI (0.11, 0.54), p=0.003. 63% of patients that had HER2/neu specific T cells at baseline continued to have responses at long-term follow-up. Increased HER2/neu specific T-cell response 1 month after the vaccine series was associated with a 0.47-log increase in T-cell response at long-term follow-up, 95% CI (0.27, 0.67), p=2e-5. 74% of patients that had an increased IFN-γ HER2 response 1 month after vaccines retained immunity long-term. As the 1-month post-vaccination series precursor frequency of HER2+IFN-γ T-cell responses increased, the probability of retaining these responses long-term increased (OR=1.49 for every one natural log increase of precursor frequency, p=0.0002), reaching an OR of 20 for a precursor frequency of 1:3,000ConclusionsPatients not destined to achieve long-term immunity can be identified immediately after completing the vaccine series. Log-fold increases in antigen-specific precursor frequencies after vaccinations correlate with increased odds of retaining long-term HER2 immune responses. Further vaccine boosting or immune checkpoint inhibitors or other immune stimulator therapy should be explored in patients that do not develop antigen-specific T-cell responses to improve overall response rates.

Tumor markers should be measured regularly and accurately to prevent, diagnose, and monitor cancers efficiently. We aimed to characterize the pre-analytical factors effecting on the analytical performance of point-of-care test (POCT) platform IchromaTM II (Boditech Med Inc., Gangwon-do, Korea) for alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and prostate specific antigen (PSA) and evaluate their consequences in clinical practice. Based on comprehensive evaluation for the analytical performance of IchromaTM II including precision, linearity, and method comparison performed according to CLSI guidelines, pre-analytical factors of sample types and conditions were extensively analyzed. A total of five sample types [serum, plasma (PL) and whole blood (WB) from EDTA tube, PL and WB from sodium heparin tube] from 40 patients were used for comparing among specimen types. Additionally, stability was assessed up to 21 h at room temperature, refrigerated for 8 days, and frozen for 16 weeks by using 4 levels of pooled patient samples which were measured in triplicate. Precision, linearity and correlation with central laboratory analyzers observed in all three tumor markers were within acceptable criteria. However, variable degrees of percent deviations were observed according to sample type and storage conditions. Only EDTA PL samples presented clinically acceptable percentage biases for all three tumor markers when stored at room temperature or refrigerated condition. Positive bias of CEA and PSA in storage duration until 16 weeks were observed when stored in frozen condition. While IchromaTM II showed an adequate analytical performance as a POCT platform with simple operating procedures for the measurement of tumor markers, clinical laboratories should be aware of stability issues when different types of blood specimens are practically utilized.

Jeongyun Bae, M.D., Won Kee Ahn, M.D., Jaehyeok Jang, M.D., Hanmil Jang, M.D., Hyein Kang, M.D., John Hoon Rim, M.D., Ph.D., Seung Min Hahn, M.D., Jung Woo Han, M.D., Chuhl Joo Lyu, M.D., Ph.D., and Jong-Baeck Lim, M.D., Ph.D.. Ann Lab Med 2024;44:97-9. https://doi.org/10.3343/alm.2024.44.1.97

Background While the real-world impact of estimated glomerular filtration rate (eGFR) equation change on clinical outcome in a longitudinal cohort setting is limited, external valuation of equation performance should be performed in different population cohorts. This study aimed to compare differential impacts of eGFR values, calculated by 5 equations in a Korean patient population, on clinical outcomes.Methods This retrospective longitudinal follow-up cohort study analyzed 23 246 participants with standardized creatinine/cystatin C assay-based laboratory results. The primary exposure was baseline eGFR calculated by 5 different equations including the recently developed 2021 race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. Clinical outcomes including all-cause mortality, renal replacement therapy, and albuminuria were analyzed to estimate the hazard ratio of the eGFR on clinical outcomes.Results Among the 5 equations, CKD-EPI 2021 with creatinine and cystatin C (CKD-EPI 2021-CrCys) showed an earlier increase in hazard ratios for all clinical outcomes, while CKD-EPI 2012 with cystatin C showed a higher hazard ratio for all-cause mortality at low eGFR. Replacing CKD-EPI 2012 with CKD-EPI 2021-CrCys, 5.4% of patients with mortality and 3.3% of patients who received renal replacement therapy were reclassified to a lower risk stage.Conclusions The 2021 CKD-EPI equations were acceptable in a Korean population, with better predictive power for clinical outcomes when compared to previous equations. The updated race-free factors for eGFR calculation improved identification of patients at risk for clinical outcomes.

BACKGROUND:Amikacin, an aminoglycoside antibiotic, is widely used for the treatment of nontuberculous mycobacterial (NTM) infections. To date, therapeutic drug monitoring (TDM) of amikacin has primarily relied on the measurement of peak and trough levels as indicators rather than the 24-hr area under the concentration-time curve (AUC24). METHODS:NTM patients referred for amikacin TDM from March 2021 to May 2023 were assessed for the AUC24 values based on administered dose. We investigated re-admission rates, all-cause mortality and AFB smear results to evaluate clinical outcome based on the actual AUC24 values. Ototoxicity and nephrotoxicity were also investigated as adverse effects in correlation with TDM parameters. RESULTS:Among 65 patients, the mean and median values of AUC24 were 234 and 249 mg·hr/L, respectively. In a group of patients with AUC24 values less than 250 mg·hr/L, 42.4 % of patients were re-admitted for pulmonary symptoms. On the contrary, another group with AUC24 values equal to or more than 250 mg·hr/L, had lower re-admission rates (25.0 %). They also showed lower all-cause mortality rates and more improvement on acid-fast bacilli smear results. Moderate to poor correlation between AUC24 values and peak/trough levels were observed. Ototoxicity and nephrotoxicity were revealed to be associated with drug exposure duration rather than AUC24 values. CONCLUSION:In this study, we performed comparative assessment of trough/peak level, traditional clinical marker for amikacin TDM, and AUC24 value. Although AUC24 values showed poor to moderate correlation to trough/peak levels, higher AUC24 correlated with favorable clinical outcomes without additional risk of toxicity.

Introduction:Although estimated glomerular filtration rate (eGFR) are continuously developed for pediatric population, impact of height measurement is often neglected due to variable dynamic growth changes in children. This study aimed to compare differential impacts of eGFR values calculated by six equations that do not use height information. Materials and methods:3503 Korean pediatric patients with creatinine/cystatin C assay-based laboratory results from 2008 to 2021 were analyzed for clinical course using a total of 8113 laboratory test results. Baseline eGFR was calculated by eight different equations including two widely used equations incorporating height parameter. Along with the agreement of CKD (chronic kidney disease) stage categorization by different equations, clinical outcome of incident CKD diagnosis in 13 years of study period were compared. Results:Among a total of 28 pairwise comparisons among eight equations, only 4 combinations of comparisons revealed optimal P15 values (≥80 % concordance), with FAS-age equation being both concordant with two equations using height parameter. Clustering of eight equations by incident CKD diagnosis in subsequent tests also highlighted FAS-age as candidate equation within the same cluster with Schwartz-bedside and FAS-height equations. When the equation values were classified into Kidney Disease Improving Global Outcomes (KDIGO) CKD stages, the distribution patterns for stage 1 and 5 were significantly different among eGFR equations. FAS-age equation revealed the highest agreement with Schwartz-bedside and FAS-height equations that incorporate the height data. Conclusions:The eGFR equation type should be considered to establish the eGFR intervals for CKD stage classification, particularly in the pediatric patient population. Cautious interpretation is required for eGFR value along with clinical context.

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Background:Despite the superiority of non-HDL cholesterol (non-HDL-C) and apolipoprotein B (ApoB) as lipid markers for atherosclerotic cardiovascular disease (ASCVD), these are only suitable as secondary markers. We compared LDL cholesterol (LDL-C), non-HDL-C, and ApoB concentrations with respect to the occurrence of cardiovascular disease in adults enrolled in the Korean Genome and Epidemiology Study (KoGES).Methods:We used information on age; sex; medical history; family history of ASCVD; current lipid-lowering therapy; current smoking status; and creatinine, total cholesterol, HDL-C, LDL-C, triglyceride, and ApoB concentrations from 5,872 KoGES participants without ASCVD. New ASCVD development was monitored during the 8-year follow-up period. Adjusted hazard ratios (aHRs) for ASCVD of LDL-C, non-HDL-C, and ApoB concentrations were calculated based on the multivariate Cox regression analyses. The participants were also grouped as low and high according to the median values for each lipid marker, and calculated aHRs of each group combined by two lipid makers.Results:ApoB showed the highest aHR per 1-SD for ASCVD (1.26; 95% confidence interval [CI], 1.11-1.43), followed by non-HDL-C (1.25; 95% CI, 1.11-1.41) and LDL-C (1.20; 95% CI, 1.06-1.37). The group with low LDL-C and high ApoB concentrations had a significantly higher aHR for ASCVD (1.61; 95% CI, 1.05-2.48) compared to the reference group values (low LDL-C and low ApoB concentrations). The aHR for the group with high LDL-C and low ApoB concentrations was not significant (1.30; 95% CI, 0.79-2.16).Conclusions:ApoB, non-HDL-C, and LDL-C are independent risk factors for ASCVD. Increases in the aHR per 1-SD for ASCVD were more strongly affected by ApoB, followed by non-HDL-C and LDL-C. Participants with low LDL-C and high ApoB concentrations showed increased ASCVD risk. For individuals with ASCVD risk factors, even those presenting normal LDL-C concentrations, measuring ApoB concentrations can provide useful information for better evaluation of ASCVD risk.

Introduction COVID-19 is known to induce plasma cell differentiation by elevating interleukin-6 level. Proliferation of dyscrasic plasma cells lead to production of monoclonal immunoglobulins. Cases with monoclonal gammopathy in COVID-19 have been reported in various countries. In this study, we present nine cases of Korean patients diagnosed with COVID-19 infection, and their consecutive electrophoresis results of monoclonal gammopathies. Material & Methods A total of 34 serial serum samples from 9 patients diagnosed with COVID-19 infection were analyzed for the protein electrophoresis, immunofixation, immunoglobulin quantification, SARS-CoV-2 antibody titers and interleukin-6 level assessments. Cases were classified into four groups based on the disease severity. Results Six cases revealed the presence of monoclonal paraprotein in serum electrophoresis results. Both two expired cases showed monoclonal bands, with one case of notable correlation with the increase of virus activity. Types of immunoglobulins were variable among six cases. Most of the cases showed high interleukin-6 levels and COVID-19 antibody titers, but their fluctuations did not correlate with monoclonal paraprotein patterns. Conclusions In conclusion, monoclonal paraproteins were observed with relatively higher frequency in the severe cases rather than mild cases. Longitudinal monitoring on monoclonal paraproteins associated with COVID-19 infection were proved to be transient in mild cases.

Background: Accurate measurement of glycated hemoglobin (HbA1c) is crucial for a diabetes diagnosis and subsequent patient management. The detection method and presence of variant Hb can interfere with HbA1c measurements. We evaluated the HbA1c-measuring performance of the DxC 700 AU (Beckman Coulter, Brea, CA, USA) immunoassay based device in comparison with another immunoassay device and the reference method.Methods: A total of 120 normal and 14 variant Hb samples were analyzed using the Co bas c 513 (Roche Diagnostics, Mannheim, Germany) and DxC 700 AU analyzers. Variant Hb samples were also analyzed using the reference method, along with 20 normal samples. The accuracy, precision, linearity, and carryover were determined.Results: DxC 700 AU results strongly correlated with those of Cobas c 513 and exhibited accuracy in comparison with the reference method. The within-run, between-run, between day, and total imprecision (%CV) values for the low-and high-concentration control materials were below 2%. The results of DxC 700 AU were linear over a wide HbA1c range (3.39%-18.30%). Although DxC 700 AU performed well in the presence of variant Hb, the HbA1c concentration was underestimated in the presence of fetal Hb. The possibility of interference from a high HbH proportion could not be ruled out.Conclusions: The overall analytical performance of DxC 700 AU was acceptable. The device is accurate, precise, and linear over a wide HbA1c concentration range. Although DxC 700 AU results highly correlated with those of Cobas c 513, caution should be exercised in cases of high HbF and HbH concentrations.

Objectives: Free light chain (FLC) is used for the diagnosis and prediction with regard to the progression risk of plasma cell disorders and Freelite reagent using the SPAplus analyzer (The Binding Site) has been one of the widely used option. However, N Latex FLC reagent with the Atellica CH 930 analyzer (Siemens Healthineers) has shown the advantages of automation and high throughput. We aimed to evaluated clinical implication by differential analytical performances of two assays.Methods: A total of 322 serum samples were collected from 193 patients requested for FLC analysis including 131 multiple myeloma patients. The precision, linearity, dilution recovery of N Latex FLC assay was evaluated. We compared the two assays and analyzed the monomer-dimer pattern for discrepant results.Results: The precision, linearity, and dilution recovery performance was appropriate for the routine use in clinical laboratories. Despite the good correlation within normal range, proportional bias up-to 170% was observed in samples with high concentrations especially for lambda. The higher value samples with N Latex FLC assay contained more monomer forms than controls. All opposite changes of FLC burden by the N Latex FLC assay proved to present concordant dynamic changes when assessed by serum protein electrophoresis.Conclusions:Clinical laboratories should be aware of the inter-assay variability of FLC quantitative measurements using different platforms, especially for high concentrations of both kappa and lambda measurements, possibly due to monomer/dimer ratio diversity. Clinical interpretations for multiple myeloma disease status might not be dramatically affected only when the same assay is utilized during follow-up periods.

BACKGROUND:Pediatric cancer patients undergoing chemotherapy or radiation therapy generally require a central venous catheter (CVC). However, serum drawn from CVCs has several drawbacks for use in routine chemistry tests. Biochemical analytes were evaluated using heparin plasma instead of serum to maintain turnaround time and to prevent problems caused by micro-clot formation or delayed clotting time. METHODS:Venous blood samples from 52 pediatric oncology patients with chemoports or Hickman catheters were collected in serum separating tubes (SSTs) and lithium heparin tubes (LHTs). A total of 29 parameters were analyzed on a Cobas c702 (Roche Diagnostics, Mannheim, Germany). Passing-Bablok regression and Bland-Altman difference plots were used for statistical analyses. RESULTS:When the mean value of each analyte measured from LHT was compared with those from SST, percentage bias was within the desirable bias limit in most of the analytes. However, albumin, potassium, and inorganic phosphorus showed a negative constant bias of -3.0%, -5.3%, and -1.6%, respectively, and total protein showed a positive constant bias of + 3.8%. CONCLUSIONS:The use of LHTs for sample collection from pediatric patients with CVCs could be helpful for routine chemistry analyses. The results of potassium and total protein should be interpreted with consideration of the difference between serum and plasma samples.