Report on the Project for Establishment of the Standardized Korean Laboratory Terminology Database, 2015

The National Health Information Standards Committee was established in 2004 in Korea. The practical subcommittee for laboratory test terminology was placed in charge of standardizing laboratory medicine terminology in Korean. We aimed to establish a standardized Korean laboratory terminology database, Korea-Logical Observation Identifier Names and Codes (K-LOINC) based on former products sponsored by this committee. The primary product was revised based on the opinions of specialists. Next, we mapped the electronic data interchange (EDI) codes that were revised in 2014, to the corresponding K-LOINC. We established a database of synonyms, including the laboratory codes of three reference laboratories and four tertiary hospitals in Korea. Furthermore, we supplemented the clinical microbiology section of K-LOINC using an alternative mapping strategy. We investigated other systems that utilize laboratory codes in order to investigate the compatibility of K-LOINC with statistical standards for a number of tests. A total of 48,990 laboratory codes were adopted (21,539 new and 16,330 revised). All of the LOINC synonyms were translated into Korean, and 39,347 Korean synonyms were added. Moreover, 21,773 synonyms were added from reference laboratories and tertiary hospitals. Alternative strategies were established for mapping within the microbiology domain. When we applied these to a smaller hospital, the mapping rate was successfully increased. Finally, we confirmed K-LOINC compatibility with other statistical standards, including a newly proposed EDI code system. This project successfully established an up-to-date standardized Korean laboratory terminology database, as well as an updated EDI mapping to facilitate the introduction of standard terminology into institutions.

Chromosomal Abnormalities in Myelodysplastic Syndrome with Near-tetraploidy: A Case Report

Massive hyperdiploidy and tetraploidy are rare cytogenetic abnormalities in myelocytic malignancies, especially in myelodysplastic syndrome (MDS). These abnormalities are known to be associated with leukemogenesis, leukemic transformation and poor prognosis. We report here the first case of MDS with near-tetraploid cytogenetic abnormality in Korea. A 80-yr-old male was diagnosed with refractory anemia with excess blasts-2 (RAEB-2). Bone marrow aspiration smear showed 16% of blasts, which were large sized myeloid blasts with irregular margins and cytoplasmic vacuolation. Cytogenetic analysis of bone marrow cells revealed numercal and structural cytogenetic abnormalities including near-tetraploidy in 8 of 20 metaphases: 45,XY,add(1)(p36.1),del(10)(p11.2),del(11)(q13),-12,-16,der(17)t(11;17) (q13;q21),add(20)(q13.1),+mar[8]/85~90,idemx2[cp8]/46,XY[4]. After chemotherapy with decitabine, he showed pancytopenia during follow-up period and died of sepsis 14 months after the diagnosis.

Epidemiologic Features of Parainfluenza Virus Type 1, 2 and 3 Infection in Seoul and a Neighboring Area, 2008-2011 / 대한임상미생물학회지

BACKGROUND: Parainfluenza virus (PIV) is a significant cause of acute respiratory infections. Epidemiological information on PIV infection could be very helpful for patient management. The aim of this study was to investigate the epidemiology of PIV infection in Seoul and a neighboring area with regard to PIV type. METHODS: The diagnosis of PIV infection was made by virus isolation. The R-mix Too cell system (Diagnostic Hybrids, Inc., Athens, OH, USA) and D3 Ultra DFA Respiratory Virus Screening & ID kits (Diagnostic Hybrids, Inc.) were used for virus culture and identification. The medical records of patients with positive virus cultures were reviewed retrospectively. RESULTS: Seven hundred and ten PIV viruses (5.6%) were isolated from 12,723 specimens. The number of subjects with PIV type III, I and II was 357, 304 and 49, respectively. PIV infection showed a peak incidence in the first year of life regardless of subtypes. The most common diagnosis among all PIV subtypes was pneumonia. Lower respiratory tract infections constituted the majority (76.3%) of PIV infections. The most common diagnosis of PIV type I and II was croup and that of PIV type III was pneumonia. A difference in seasonal variation between subtypes was observed. PIV I (62.2%) was mainly isolated from July to September while PIV type III (86.8%) was isolated from April to July. CONCLUSION: Lower respiratory infection was most commonly found in hospitalized patients with PIV infection. Clinical features of PIV infection were similar those seen in Western PIV reports, with the exception of the seasonal outbreak pattern.

ABO Genotyping of a Neonate with Mixed Field Agglutination / 대한수혈학회지

Mixed field agglutination is an important, but rare phenomenon of ABO blood grouping. Contrary to adults, neonatal red blood cells are immature and they present a weak ABO expression, and sometimes this result in a mixed field agglutination pattern. We report here on a case of a neonate who presented with mixed field agglutination on the ABO blood grouping during serologic testing and the neonate had a normal ABO genotype.

Immune Hemolytic Anemia after ABO-mismatched Liver Transplantation: A Case Report / 대한수혈학회지

Limitations due to lack of appropriate available donors for liver transplantation necessitates the use of ABO-mismatched donors. Transplantation of ABO-mismatched solid organs is sometimes associated with the development of immune hemolytic anemia, which is caused by production of antibodies by the donor B lymphocytes in a primary or secondary immune response against the recipient's red blood cell antigens. This condition is referred to as Passenger Lymphocyte Syndrome (PLS). PLS is more frequent in heart and lung transplants than in liver and kidney transplants with incidence of PLS in liver transplantation at 30~40%. When present, PLS typically manifests 1~3 weeks after transplantation, and subsides within 3 months after symptoms are first detected. In most patients, PLS is self-limiting and exhibits mild symptoms, but in some cases PLS can be life-threatening. We report a case of immune hemolytic anemia after an ABO-mismatched liver transplantation involving a blood group O donor and a blood group A recipient, and successful treatment of the resulting PLS symptoms by transfusion of gamma-irradiated group O Red Blood Cells (RBCs) accompanied by administration of 60 mg/day of methylprednisolone for 1 week.

A Case of Anti-Sda Proven by Urine Neutralization Test

Anti-Sda is of no clinical significance, because it rarely causes hemolytic transfusion reactions. Even when its presence is suspected during antibody screening test, further identification of the antibody is usually not performed. We experienced a case of anti-Sda in 73 yr-old male patient showing mixed field agglutination by microcolumn agglutination. Antibody specificity could not be identified by conventional antibody identification test, and it was proven to be anti-Sda by urine neutralization test. In spite of its little clinical significance, it may give incompatible crossmatching results reacting with Sda antigen, which occurs at a high frequency in general population. When incompatible crossmatch results arising from anti-Sda are suspected, the problem may be solved by using the urine-neutralized serum of in crossmatching test.

Evaluation of ABO Antibody Titration Using Tube and Column Agglutination Techniques

BACKGROUND: ABO antibody titration is useful for the evaluation of ABO-incompatible bone marrow or solid organ transplantations, yet the results quite vary between different test methods used. We compared the results of microcolumn agglutination and tube methods. METHODS: Anti-A and anti-B isoagglutionin titers were determined in 63 healthy individuals (23 O, 20 A, and 20 B blood groups) using 4 different methods: immediate spin tube (tube), microcolumn agglutination without anti-human globulin (AHG) (CAT), tube with AHG (tube-AHG) and microcolumn agglutination with AHG (CAT-AHG). RESULTS: The median (range) titers of anti-A and anti-B in group O individuals by tube, CAT, tube-AHG, and CAT-AHG methods were 64 (8-512), 64 (8-512), 128 (8-2,048), and 128 (16-2,048); 64 (16-128), 128 (16-256), 128 (16-512), and 256 (16-512), respectively. The median (range) titers of anti-A in group B and anti-B in group A individuals by the four methods were 64 (16-128), 128 (8-128), 128 (8-256), and 256 (8-256); 64 (8-128), 64 (8-128), 32 (8-128), and 64 (8-256), respectively. The isoagglutinin titer measured by CAT-AHGmethod was the highest. The titers measured by CAT and CAT-AHG methods were 0-1 titer higher than those by tube and tube-AHG methods, respectively. Whatever method was used, the isoagglutinin titers were higher in women than in men. CONCLUSIONS: CAT-AHG was the most sensitive method among the four methods tested. Since AHG titer values are critical for the clinical management and CAT has less manual procedures than tube method, CAT-AHG method could be used for the standardization of ABO antibody titration in different institutions.

Clinical Characteristics and Comparison of the Various Methods Used for the Diagnosis of the New Influenza A Pandemic in Korea

BACKGROUND: Laboratory diagnosis of new influenza A (H1N1) is crucial for managing patients and establishing control and prevention measures. We compared the diagnostic accuracies of the real time RT-PCR (rRT-PCR) test recommended for the confirmation of the new flu and the viral culture method used conventionally for viral disease with that of the rapid antigen test (RAT). METHODS: We performed RAT, R-mix culture, and real-time PCR by using 861 respiratory samples collected from December 2009 to January 2010 and evaluated the abilities of these methods to detect new influenza A. The relationship among the positive rates of RAT, grades of culture, and the cycle threshold (Ct) values of rRT-PCR was also evaluated. RESULTS: Of the 861 patients, 308 (35.8%) were diagnosed with new influenza A. The sensitivities, specificities, positive predictive values, and negative predictive values of the tests were respectively as follows: 59.7%, 99.5%, 98.4%, and 81.6% for RAT; 93.2%, 100%, 100%, and 96.3% for R-mix culture; and 95.8%, 100%, 100%, and 97.7% for rRT-PCR. Samples with weak positive grade in culture and those with Ct values of 30-37 in rRT-PCR showed positivities as low as 25.3% and 2.3% in RAT, respectively. The hospitalization rate and death rate of the confirmed patients were 3.2% and 0.3%, respectively, and gastrointestinal symptoms were observed in 7.2% of the patients. CONCLUSIONS: R-mix culture and rRT-PCR tests showed excellent reliability in the diagnosis of new influenza A and could be very useful, especially for samples with low viral load.

Evaluation of the Automated Instrument QWALYS-3 for Unexpected Antibody Screening / 대한수혈학회지

BACKGROUND: The use of automated techniques reduces the impact of human errors in blood banking and it improves the standardization and the quality of the achieved results. Erythrocyte Magnetized Technology (EMT) is now being widely used due to its simplicity and efficiency for detecting alloantibody. We evaluated the antibody screening test of the QWALYS-3 (DIAGAST, Loos Cedex, France). METHODS: The evaluation focused on antibody screening using the QWALYS-3 as compared to the standard manual tube method and the Ortho BioVue system in clinical samples (n=100) and frozen stored samples (n=64), which had RBC alloantibody. RESULTS: Using the manual tube method, the sensitivity of antibody screening was 100% by the QWALYS-3 and 42.8% by the Ortho BioVue in the clinical samples (n=7) and 2 results were discrepant by the QWALYS-3 for negative samples. For the known antibodies from the frozen stored samples (n=64) this correspondence rate amounted to 93.7% (n=60). CONCLUSION: The QWALYS-3 system displayed a good match rate with the Ortho BioVue system (92%). It also showed reliable results for the general accuracy when compared to the manual method (concordance rate: 98%). The QWALYS-3 system will facilitate the automation of routine antibody screening with high reliability, sensitivity and specificity compared to the standard manual methods.

A Case of Hemophagocytic Lymphohistiocytosis with Clonal Karyotype Abnormalities

There have been a few reports of hemophagocytic lymphohistiocytosis (HLH) with chromosomal abnormalities. Clonal chromosomal abnormalities in HLH patients are usually found in association with hematologic malignancies and rarely with epstein-barr virus (EBV) infection. Here, we report a fatal case of HLH with clonal karyotype abnormalities. A 75-yr-old man was admitted with persistent anorexia and high fever. Laboratory data revealed pancytopenia, hypofibrinogenemia, hyperferritinemia, prolonged prothrombin time and activated partial thromboplastin time, and marked elevated level of serum transaminases. In real time-PCR using whole blood, EBV DNA was not detected but cytomegalovirus (CMV) DNA was detected. The bone marrow aspiration smear showed hyperplasia of mature histiocytes with prominent hemophagocytosis. In chromosomal analysis of bone marrow aspirates, complex chromosomal abnormalities were found. In spite of steroid pulse therapy and antibiotic treatment, he died of disseminated intravascular coagulopathy.

Evaluation of the LG Advansure(TM) Malaria P.f./P.v. real-time QPCR for the Diagnosis of Malaria

BACKGROUND: Malaria is a problematic disease in Korea, and microscopic examination of Giemsa-stained blood smear has been used as the gold standard for its diagnosis. However, this technique is time-consuming and has low sensitivity in samples with low numbers of malarial parasites (<20 parasites/microL). Here, we evaluated the performance characteristics of the LG Advansure(TM) Malaria P.f./P.v. real-time QPCR (LG life sciences, Korea). METHODS: Blood samples from 173 persons who visited Korea University Ansan Hospital were evaluated. QPCR was performed in 73 malaria patients and 100 healthy subjects by using the LG Advansure Malaria P.f./P.v. real-time QPCRR kit, and the results were compared with those of microscopy. The detection limit of this kit was determined by serial dilution of Plasmodium-infected blood with normal blood (blood not infected with Plasmodium). RESULTS: Among the 73 patients that were microscopically confirmed to have malaria (Plasmodium vivax infection, N=70, P. falciparum infection, N=3), 69 patients were diagnosed with P. vivax infection and 3 were diagnosed with P. falciparum infection by LG Advansure(TM) Malaria P.f./P.v. real-time QPCR. Both the tests indicated absence of infection in the 100 healthy subjects. The detection limit of LG Advansure(TM) Malaria P.f./P.v. real-time QPCR was 0.1 parasite/microL. CONCLUSIONS: LG Advansure(TM) Malaria P.f./P.v. real-time QPCR is a very sensitive and specific technique and can be used as a confirmatory test for malaria.

A Case of Atypical Chronic Myeloid Leukemia with the JAK2V617F Mutation

Atypical chronic myeloid leukemia (aCML) is a rare leukemic disorder that shows myelodysplastic and myeloproliferative features simultaneously. The Janus kinase 2 gene V617F mutation (JAK2V617F) in aCML has been the source of much controversy. Some JAK2V617F positive cases have been reported but others observed no JAK2V617F mutation in aCML as defined by WHO classification. Recently, we experienced a case of aCML with JAK2V617F mutation with typical myelodysplastic/myeloproliferative features in peripheral blood and bone marrow aspirates. The karyotype was normal and no BCR/ABL1, PDGFRA or PDGFRB gene rearrangement was noted with FISH analysis. JAK2V617F mutation of the case was identified with amplification refractory mutation system PCR and direct sequencing. We also studied JAK2V617F mutation status in 3 additional cases of previously diagnosed aCML in our institution, but no mutation was identified.

Human Bocavirus in Patients with Respiratory Tract Infection / 대한진단검사의학회지

BACKGROUND: Human bocavirus (HBoV) is a newly identified viral pathogen, and its clinical epidemiology and significance in respiratory infections have not yet been completely elucidated. We investigated the prevalence of HBoV infection and the association between viral (HBoV) load and clinical features of the infection in patients of all age-groups. METHODS: Nasopharyngeal aspirates from patients with symptoms of respiratory infection were tested for presence of HBoV by using real-time polymerase chain reaction. HBoV-positive patients were categorized into low- and high-viral-load groups using 1.0x10(6) copies/mL as the threshold value of viral load. RESULTS: Detection rate of HBoV was 4.8% (N=93) in a total of 1,926 samples with peak incidence of infection being observed in patients aged 6-12 months. HBoV infection was more frequently observed in young children, especially, in children aged less than 5 yr, and the HBoV load decreased with increase in age. HBoV was codetected with other respiratory viruses in 17 (18.3%) of the 93 HBoV-positive patients and 15 patients (88.2%) belonged to the low-viral-load group. Patients infected with HBoV alone showed a higher viral load than those patients in whom HBoV was codetected with other respiratory viruses (median load, 3.78x10(5) copies/mL vs. 1.94x10(4) copies/mL, P=0.014). Higher pulse rate (P=0.007) and respiratory rate (P=0.021) were observed in patients with a high-viral-load. CONCLUSIONS: Our results suggest that HBoV may be the causative agent of respiratory infection in the high-viral-load group.

Human Bocavirus in Patients with Respiratory Tract Infection / 대한진단검사의학회지

BACKGROUND: Human bocavirus (HBoV) is a newly identified viral pathogen, and its clinical epidemiology and significance in respiratory infections have not yet been completely elucidated. We investigated the prevalence of HBoV infection and the association between viral (HBoV) load and clinical features of the infection in patients of all age-groups. METHODS: Nasopharyngeal aspirates from patients with symptoms of respiratory infection were tested for presence of HBoV by using real-time polymerase chain reaction. HBoV-positive patients were categorized into low- and high-viral-load groups using 1.0x10(6) copies/mL as the threshold value of viral load. RESULTS: Detection rate of HBoV was 4.8% (N=93) in a total of 1,926 samples with peak incidence of infection being observed in patients aged 6-12 months. HBoV infection was more frequently observed in young children, especially, in children aged less than 5 yr, and the HBoV load decreased with increase in age. HBoV was codetected with other respiratory viruses in 17 (18.3%) of the 93 HBoV-positive patients and 15 patients (88.2%) belonged to the low-viral-load group. Patients infected with HBoV alone showed a higher viral load than those patients in whom HBoV was codetected with other respiratory viruses (median load, 3.78x10(5) copies/mL vs. 1.94x10(4) copies/mL, P=0.014). Higher pulse rate (P=0.007) and respiratory rate (P=0.021) were observed in patients with a high-viral-load. CONCLUSIONS: Our results suggest that HBoV may be the causative agent of respiratory infection in the high-viral-load group.

A Patient with Fatal Septicemia Caused by a Rare Pathogen Dermabacter Hominis / 감염과화학요법

Dermabacter hominis (D. hominis) is a recently discovered gram-positive bacterial species, and it is usually recognized as an opportunistic human pathogen. Very few documented cases of severe infections caused by Dermabacter hominis have been published. In this report, we describe a case of fatal septicemia caused by Dermabacter hominis.

A Case of Therapy-related Acute Lymphoblastic Leukemia with t(11;19)(q23;p13.3) and MLL/MLLT1 Gene Rearrangement / 대한진단검사의학회지

Therapy-related ALL (t-ALL) is a rare secondary leukemia that develops after chemotherapy and/or radiotherapy for primary malignancies. Chromosomal 11q23 abnormalities are the most common karyotypic alterations in t-ALL. The t(11;19)(q23;p13) aberration is extremely rare and has not been confirmed at the molecular genetic level. Here, we report a case of t-ALL with t(11;19)(q23;p13.3) and MLL-MLLT1 (alias ENL) gene rearrangement confirmed by cytogenetic analysis, multiplex reverse transcription-PCR (multiplex RT-PCR), and DNA sequencing in a patient who had undergone treatment for breast cancer. A 40-yr-old woman developed acute leukemia 15 months after undergoing 6 cycles of adjuvant chemotherapy (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2), radiation therapy (dose, 5,900 cGy), and anticancer endocrine therapy with tamoxifen. The complete blood cell counts and bone marrow examination showed increased blasts and the blasts showed B lineage immunophenotype (positive for CD19, CD34, and cytoplasmic CD79a). Cytogenetic analysis revealed the karyotype 47,XX,+X,t(11;19)(q23;p13.3)[4]/46,XX[16]. FISH analyses, multiplex RT-PCR, and DNA sequencing confirmed the MLL-MLLT1 gene rearrangement. The patient underwent induction chemotherapy with fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (Hyper-CVAD) and achieved complete remission. Subsequently, she underwent consolidation chemotherapy, but died of brain ischemia in the pons and the region of the middle cerebral artery. To our knowledge, this is the first case report of t-ALL with t(11;19)(q23;p13.3) and the MLL-MLLT1 gene rearrangement.

Characteristics of Intron 6 Nucleotide Sequences of cis-AB in Koreans / 대한수혈학회지

BACKGROUND: The cis-AB is a very rare phenotype in the ABO blood group system. It corresponds to a special ABO allele that encodes glycosyltransferase that is capable of synthesizing both A and B antigens. Until now, the exon 6 and 7 gene sequences of cis-AB alleles are well known. In this study, we report on the intron 6 sequence structure of the cis-AB allele. METHODS: Standard serologic tests for the ABO blood group phenotypes were performed in four cis-AB samples. Allele-separation by cloning and subsequent sequencing was carried out. RESULTS: The results showed that intron 6 of cis-AB is almost identical to the A101 allele except for three single nucleotide polymorphisms at nucleotide positions 163, 179 and 662, where the nucleotides of the A101 replace those of B101. CONCLUSION: The intron 6 sequences of cis-AB in Koreans have both A101 and B101 blood group sequences.

Using Genotyping to Identify an A1B(weak) Blood Group / 대한수혈학회지

Since an exact ABO blood type match is essential for transfusion therapy, any ABO discrepancies should be resolved prior to the issuing of blood. The authors confirmed the ABO blood group of a 50-year-old male using genotyping. On a routine blood group test, the cell type was A+; however, anti-B was undetected in his serum. To determine the cause of this ABO discrepancy, an adsorption elution test and saliva test were performed. The presence of a weak B substance was suspected despite no evidence of the B antigen on red blood cells. Polymerase-chain-reaction restriction-fragment-length-polymorphism (PCR-RFLP) and sequencing analysis of exons 6 and 7 demonstrated that his blood type was A1Bweak (the A allele tested as the A105 subtype, while the B allele was most similar to the B302 subtype). Again, using genotyping, we subsequently confirmed the A1Bweak blood type in a leukemic patient who was in complete remission.

The Frequency of Unexpected Antibodies by Using Two Micro-column Agglutination Systems: DiaMed-ID and Ortho BioVue Systems / 대한수혈학회지

BACKGROUND: Unexpected antibody screening and identification tests are very important for safe blood transfusion. The micro-column agglutination test (MCAT) is widely used due to its simplicity and efficiency for detecting alloantibodies. We analyzed the frequency of unexpected antibodies at three university hospital blood banks, which use two different MCAT systems. METHODS: From February 2002 to December 2009, a total of 295,876 unexpected antibody screening tests were performed at three university hospital blood banks. Two hospital blood banks (Anam and Ansan Hospitals) used the DiaMed-ID system (DiaMed Ag, Switzerland) and the other (Guro Hospital) used the Ortho BioVue system (Ortho-Clinical Diagnostics, USA) for antibody screening and identification tests. RESULTS: The rates of detecting unexpected antibodies on screening test based on the 'tests performed' and the 'persons tested' were 1.16% per test and 0.96% per person in Korea University Guro Hospital, 0.65% and 0.41% in Korea University Anam Hospital and 0.76% and 0.57% in Korea University Ansan hospital, respectively. There were significant differences in the frequencies based on the two different systems (P<0.001). Among the warm antibodies, Rh antibodies were more frequently detected by the DiaMed-ID system, and Lewis antibodies were most frequently detected by the Ortho BioVue System. CONCLUSION: We should carefully interpretate the frequency of unexpected antibodies in the Korean population because the frequencies of unexpected antibodies are different according to different employed micro-column agglutination systems.

Evaluation of Various Formulae for Glomerular Filtration Rate Estimation and Proposal of New Formulae for the Korean Population / 대한진단검사의학회지

BACKGROUND: Some researchers have questioned the necessity of adjusting glomerular filtration rate (GFR) by body surface area (BSA). We compared the relationship between estimated GFR (eGFR) and radionuclide GFR (rGFR) with or without BSA adjustment by comparing the results obtained using various formulae with those obtained using 2 new proposed formulae. METHODS: A retrospective study was performed using 204 Korean individuals whose GFR had been estimated by the (99m)Tc-diethylenetriaminepentaacetic acid method between March 2004 and July 2008. We used the modification of diet in renal disease (MDRD) II formula, Mayo clinic quadratic (MCQ) formula, Cockcroft-Gault (CG) formula, and lean body mass-adjusted CG formula. Two new formulae, skeletal muscle mass index (SMI)-adjusted CG formula and SMIx3.4/SCr, were proposed by us. We analyzed each parameter with Pearson's correlation coefficient and also obtained the bias values. RESULTS: BSA did not satisfy the fundamental prerequisites of an adjustment factor for rGFR. MDRD II and MCQ GFR estimates demonstrated higher Pearson's correlation coefficient with BSA-unadjusted rGFR than they did with BSA-adjusted rGFR. The other GFR formulae estimates showed better correlation with rGFR and more favorable bias (P<0.001) when both GFR estimates and rGFR values were BSA-unadjusted. SMI-adjusted CG and SMIx3.4/SCr GFR estimates demonstrated correlation with rGFR and bias values similar to those of the MDRD II and CG GFR estimates. CONCLUSIONS: We suggest that absolute, non-corrected GFR and GFR estimate be preferred in daily practice. The absolute, non-corrected GFR and GFR estimate are considered helpful for patients with eGFR< or =60 mL/min/1.73 m2. We also recommend the clinical use of the new formulae, SMI-adjusted CG and SMIx3.4/SCr (BSA-unadjusted).