Increment of Serum Free Light Chain Kappa/Lambda Ratio in Patients with Renal Dysfunction

BACKGROUND: Since free light chain (FLC) is metabolized in the kidney, serum FLC concentration and kappa/lambda ratio are increased in patients with decreased renal function, even in the absence of monoclonal protein. In this study, we measured serum FLC levels to investigate the change in kappa/lambda ratios in relation to the severity of renal dysfunction. METHODS: Serum FLC concentrations were measured in 92 archived serum samples from patients diagnosed with chronic kidney disease using the Freelite assay (The Binding Site Group Ltd., UK), and kappa/lambda ratios were calculated. Serum creatinine levels were assayed to calculate estimated glomerular filtration rate (eGFR), and patients were divided into subgroups according to Kidney Disease Improving Global Outcomes (KDIGO) guidelines. We analyzed the difference in serum FLC levels and kappa/lambda ratios between subgroups. RESULTS: Serum FLC levels and kappa/lambda ratios increased depending on the severity of renal dysfunction. When patients were classified by setting cut-off value of eGFR as 60 mL/min/1.73 m2 (group A: eGFR ≥60 mL/min/1.73 m2, group B: < 60 mL/min/1.73 m2), the kappa/lambda ratio of group B was significantly higher than that of group A (group B: 1.60±0.46 vs. group A: 1.35±0.27, P=0.018). Serum FLC kappa/lambda ratios were within the previously determined renal reference interval (0.37–3.1). CONCLUSIONS: When interpreting results of serum FLC kappa/lambda ratio, renal function status should be considered in addition to hematological findings. If renal function deteriorates, a wider renal reference interval is preferred instead of the usual reference interval.

Comparison of YD URiSCAN PluScope Urine Microscopic Analyzer and Sysmex UF-1000i Flow Cytometry Systems

BACKGROUND: Urinalysis is one of the most commonly performed tests in clinical laboratories. In this study, we compared YD URiSCAN PluScope (PluScope; YD Diagnostics Corp., Korea) and Sysmex UF-1000i (UF-1000i; Sysmex Corp., Japan) for urine microscopic sediment analysis. METHODS: A total of 404 fresh urine samples were collected and analyzed using PluScope, UF-1000i, and manual microscopy. Quantitative correlation analyses for red blood cells (RBCs), white blood cells (WBCs), epithelial cells (EC), and casts were performed using Spearman's correlation. We evaluated agreement among the three systems by using weighted Cohen's κ and calculating concordance rates within one grade of difference for semiquantitative and qualitative parameters. RESULTS: There were moderate-high correlations between PluScope and UF-1000i for RBCs, WBCs, and ECs (r=0.542, 0.714, and 0.571, respectively) but negligible correlation for casts (r=0.186). There were moderate-high correlations between manual microscopy and automated devices for RBCs, WBCs, and ECs (r=0.550–0.745) but negligible correlations for casts (PluScope: r=0.247; UF-1000i: r=0.223). The pairwise concordance rates within one grade difference among the three methods were good for RBCs, WBCs, and ECs (95.0%–99.0%, κ=0.41–0.74). For casts, the concordance rate between PluScope and manual microscopy was fair (96.8%, κ=0.25), but concordance rates between UF-1000i and manual microscopy and between the two automated devices were poor (81.2% and 81.7%; κ=0.04 and 0.06, respectively). CONCLUSIONS: The two automated urine sediment analyzers showed a moderate-high correlation and concordance rate. They showed good correlations and concordance rates for RBCs, WBCs, and ECs. However, manual microscopic examinations are still needed for reviewing and confirming the presence of pathologic particles in urine, such as casts and crystals.

Development of Educational Material for Blood Donor Interview through the Cognitive Evaluation of Donor History Questionnaires / 대한수혈학회지

BACKGROUND: Screening for healthy blood donors through donor interviews is essential to the safety of donors and blood resources. Our goal was to suggest educational material for donor interviewers and donors, as well as supplemental material for interview sites, which will help provide an effective interview process. METHODS: We conducted surveys regarding experiences in donor interviews from donor interviewers and cognitive interviews about difficulties during interview from blood donors between September and October of 2015. We additionally conducted a post-survey about provided educational and supplemental materials between December 2015 and January 2016. RESULTS: The possibility of an incorrect answer in the donor history questionnaire (DHQ) was high for questions about sexual contact, imprisonment, or medication, and the reasons were incorrect memories, ignorance about donor interview, or protection of privacy. Cognitive interviews of donors revealed questions and terminology that are difficult to understand. Donor interviewers could obtain improved understanding of the DHQ through educational materials, which were found to be useful for new interviewers or donors. Use of a supplemental flip book for the interview process was found to be useful, especially for blood centers with small blood donations. CONCLUSION: This study investigated difficulties in the donor interview from the perspective of donor interviewers and donors and suggested educational and supplemental materials to address these difficulties. These materials will induce correct and honest answers from blood donors through education and guidance about the donor interview process and help secure the safety of blood products.

Utilization of Mean Peroxidase Index for Discrimination of Pseudoneutropenia

BACKGROUND: Autoanalyzer ADVIA2120 uses intracellular peroxidase concentration to perform white blood cell (WBC) differential. Therefore, in specimens containing neutrophils with low peroxidase concentration, neutrophils can be miscounted as monocytes or large unstained cells resulting in pseudoneutropenia. Myeloperoxidase deficiency can be detected by the mean peroxidase index (MPXI). The aims of this study are to establish the reference interval of MPXI and define a cut off value for manual slide review to discriminate pseudoneutropenia. METHODS: We calculated reference intervals as mean+/-2SD according to the indirect method of CLSI C28-A3 guideline from MPXI data of 5,802 individuals who took routine health checkup from April 2010 to June 2012. We performed manual slide review on specimens with low MPXI and compared neutrophil differential count of manual method with that of autoanalyzer. When neutrophil differential in manual slide review was >20%P higher than autoanalyzer result, it was regarded as a pseudoneutropenia. We performed ROC analysis using the MPXI results of samples with and without pseudoneutropenia to define a cutoff to discriminate pseudoneutropenia. RESULTS: The reference intervals of MPXI in total population, male, and female were -4.9 to 7.5, -5.5 to 7.3, and -4.5 to 7.5, respectively. The mean value of MPXI was significantly higher in female than in male and there was no difference by age. Twenty-two pseudoneutropenia samples from 7 patients were identified. ROC analysis yielded cutoff value of -20.7 with 94.9% of sensitivity and 77.3% of specificity. CONCLUSIONS: MPXI may be used in the manual slide review guideline for detecting pseudoneutropenia.

A Case of Heterozygous alpha(+)-Thalassemia Diagnosed in a Korean Family by Using Multiplex Ligation-Dependent Probe Amplification / 임상검사와정도관리

Alpha-thalassemia (alpha-thalassemia), which is prevalent in the Mediterranean region, is caused by deficient synthesis of the alpha-globin chains. It is commonly caused by HBA1 and/or HBA2 gene deletion and is diagnosed by DNA sequence analysis. The proband was a 38-year-old woman who was found to have microcytic and hypochromic anemia on a routine health checkup. Results of the Hb electrophoresis (EP) and direct sequencing of the HBA1 and HBA2 genes were found to be normal. As multiplex ligation-dependent probe amplification (MLPA) for the HBA1 and HBA2 genes revealed heterozygous deletion, she was diagnosed with heterozygous alpha+-thalassemia. Although routine laboratory tests revealed similar findings in the proband's father, brother and niece, MLPA revealed heterozygous deletions of the HBA1 or HBA2 gene in her brother and niece. In summary, we report a case of heterozygous alpha+-thalassemia in a Korean family that was detected by MLPA. We recommend that patients with suspected hemoglobinopathies should be followed-up further with MLPA, especially when Hb EP shows a normal pattern.

Development of Indicators to Assess the Stability of Remnant Blood Samples Stored in a Biobank: Experience at One Institution / 대한진단검사의학회지

BACKGROUND: One of the major concerns with biobanking is the absence of standard operating procedures to eliminate pre-analytical variation arising from sample collection, preparation, and storage. Currently, there is a lack of tools to carry out quality control procedures for stored blood samples. The aim of this study is to assess the quality of stored blood samples in our biobank and to suggest appropriate indicators for their quality control. METHODS: The stored blood samples that we tested have been registered into our biobank since 2003. These were transferred to our biobank after carrying out routine requested tests, because the samples would have otherwise been discarded. For the purpose of quality control, we analyzed the concentrations and the integrity of DNA and RNA extracted from the stored samples and tested the levels of several serum proteins; the results were compared with the corresponding pre-storage levels. RESULTS: A total of 19 samples were stored from 2006 to 2009. Of the 22 samples stored between 2003 and 2005, 50% showed complete DNA integrity. However, sufficient RNA integrity was noted in only 1 sample stored as recently as 2009. High blood urea nitrogen levels were also noted in the stored sera, but the increase did not correlate to the duration of storage. CONCLUSIONS: The amount and integrity of nucleic acids extracted from stored blood samples are potential indicators that can be used for quality control. A guideline for the quality assessment of stored blood samples in a biobank is urgently needed.