Sample size calculation in clinical trial using R

Since the era of evidence-based medicine, it has become a matter of course to use statistics to create objective evidence in clinical research. As an extension of this, it has become essential in clinical research to calculate the correct sample size to demonstrate a clinically significant difference before starting the study.Also, because sample size calculation methods vary from study design to study design, there is no formula for sample size calculation that applies to all designs. It is very important for us to understand this. In this review, each sample size calculation method suitable for various study designs was introduced using the R program (R Foundation for Statistical Computing). In order for clinical researchers to directly utilize it according to future research, we presented practice codes, output results, and interpretation of results for each situation.

Comparison of Total and IgG ABO Isoagglutinin Titers in ABO-Incompatible Organ Transplant Patients: Analysis of Data from a University Hospital Over the Last 5 Years / 대한수혈학회지

Background@#Measurement of ABO isoagglutinin titers is important for patients who have received an ABO-incompatible organ transplant. Specifically, IgG isoagglutinin is essential for predicting graft outcomes in kidney transplantation, but many laboratories measure only the total isoagglutinin taking into consideration time and labor efficiency. In this study, we propose a useful method for predicting IgG isoagglutinin by analyzing the mathematical relationship between total and IgG isoagglutinin titers. Furthermore, the effects of patients’ characteristics of isoagglutinin were also analyzed. @*Methods@#From January 2017 to April 2022, the results of 3,676 total/IgG isoagglutinin titers of 65 patients who underwent liver and kidney transplantation were analyzed. Isoagglutinin titration was performed using the column agglutination technique with serially diluted serum samples and dithiothreitol was added for measuring IgG isoagglutinin. A generalized estimation equation (GEE) and the Deming regression were used to analyze the relationship and agreement of total/IgG isoagglutinin titers. @*Results@#In A, B, and O types, total isoagglutinin titers were 1.6 (2

Development of a Secondary Order Program for Pretransfusion Tests to Improve the Work Efficiency of Blood Bank / 대한수혈학회지

Background@#In the author’s blood bank, if the Ab screening test results are positive in the pretransfusion test, an Ab identification test and polyspecific direct antiglobulin test (DAT) are performed. IgG and C3 monospecific DATs are also performed if the polyspecific DAT is positive. To perform additional tests, clinical technologists used to communicate with the clinical department by telephone, and then the clinical doctor issued the orders.There could be problems with this process, such as clerical errors and reduced work efficiency. Therefore, this study developed the secondary order program to improve the work efficiency of the blood bank. @*Methods@#The secondary order program that allows the laboratory medicine doctors to issue additional test orders, print out barcodes in blood bank, and immediately report the results to the EMR (Electronic Medical Record) was developed. Before (Jul 2018∼Jun 2019) and after (Jul 2019∼Jun 2020) applying the program to inpatients, the number of telephone calls, Ab screening tests, Ab identification tests, polyspecific DAT, and monospecific DAT were compared to evaluate the effectiveness of the program. @*Results@#After applying the program, 515 calls per year (average 43 calls per month) were reduced. Before the program, the results of 68 Ab screening tests and 16 polyspecific DATs were not reported on EMR, but no case was missed after the program. @*Conclusion@#Through the secondary order program, the work efficiency of the blood bank was improved. It is expected that expanding this program to other blood bank tests will help implement tests faster and make them more systematic.

Development of a Secondary Order Program for Pretransfusion Tests to Improve the Work Efficiency of Blood Bank / 대한수혈학회지

Background@#In the author’s blood bank, if the Ab screening test results are positive in the pretransfusion test, an Ab identification test and polyspecific direct antiglobulin test (DAT) are performed. IgG and C3 monospecific DATs are also performed if the polyspecific DAT is positive. To perform additional tests, clinical technologists used to communicate with the clinical department by telephone, and then the clinical doctor issued the orders.There could be problems with this process, such as clerical errors and reduced work efficiency. Therefore, this study developed the secondary order program to improve the work efficiency of the blood bank. @*Methods@#The secondary order program that allows the laboratory medicine doctors to issue additional test orders, print out barcodes in blood bank, and immediately report the results to the EMR (Electronic Medical Record) was developed. Before (Jul 2018∼Jun 2019) and after (Jul 2019∼Jun 2020) applying the program to inpatients, the number of telephone calls, Ab screening tests, Ab identification tests, polyspecific DAT, and monospecific DAT were compared to evaluate the effectiveness of the program. @*Results@#After applying the program, 515 calls per year (average 43 calls per month) were reduced. Before the program, the results of 68 Ab screening tests and 16 polyspecific DATs were not reported on EMR, but no case was missed after the program. @*Conclusion@#Through the secondary order program, the work efficiency of the blood bank was improved. It is expected that expanding this program to other blood bank tests will help implement tests faster and make them more systematic.

A Case of Donor Cell Leukemia after Allogenic Peripheral Blood Stem Cell Transplantation for Acute Promyelocytic Leukemia with PML-RARA

Utility of Plasma Cell Screening Tube Kit to Differentiate Neoplastic Plasma Cells from Reactive Plasma Cells

Flow cytometry is a powerful tool for analysis of hematologic malignancies, that provides rapid, quantitative, and multiparametric analysis of heterogeneous cell populations, but requires standardization because of complexities in panel design and interpretation. Here, we compared the Plasma Cell Screening Tube (PCST) kit (Cytognos, Spain) in conjunction with EuroFlow antibody panels for standardization of flow cytometry to a conventional method for diagnosis of plasma cell dyscrasias. Thirty-nine bone marrow samples and one peripheral blood sample from 40 patients were tested. Thirty-three patients were diagnosed with multiple myeloma (MM), and seven were in a reactive state. In PCST implementation, eight antibodies were used for staining, including anti-CD45-Pacific Blue, anti-CD19-PECy7, anti-CD138-OC515, anti-CD38-FITC, anti-CD56-PE, anti-β2-microglobulin-PerCPCy5.5, anti-kappa-APC, and anti-lambda-APC-C750. Plasma cells were initially identified using CD38 and CD138; thereafter, CD38+, CD138+ gated cells were analyzed for CD56, CD19, CD45, cytoplasmic kappa, cytoplasmic lambda, and β2-microglobulin. Conventional flow cytometry was performed with six monoclonal antibodies, including anti-CD56-FITC, anti-kappa-FITC, anti-CD19-PE, anti-lambda-PE, anti-CD138-PECy5, and anti-CD45-PECy7 (Beckman Coulter, USA). Monoclonal plasma cells with cytoplasmic light-chain restriction were detected in 30 of 33 (90.9%) MM cases by conventional methods, and 32 of 33 (97.0%) MM cases with the PCST method. No differences were noted between PCST and the conventional method in immunophenotyping and plasma cell percentages (P=0.323). Among plasma cells, levels (%) were significantly higher by the PCST approach than those in the conventional method (97.6% vs 95.8%, P=0.010). PCST exhibited better performance for plasma cell dyscrasias diagnosis, and could improve laboratory efficiency and quality.

Utility of Plasma Cell Screening Tube Kit to Differentiate Neoplastic Plasma Cells from Reactive Plasma Cells

Flow cytometry is a powerful tool for analysis of hematologic malignancies, that provides rapid, quantitative, and multiparametric analysis of heterogeneous cell populations, but requires standardization because of complexities in panel design and interpretation. Here, we compared the Plasma Cell Screening Tube (PCST) kit (Cytognos, Spain) in conjunction with EuroFlow antibody panels for standardization of flow cytometry to a conventional method for diagnosis of plasma cell dyscrasias. Thirty-nine bone marrow samples and one peripheral blood sample from 40 patients were tested. Thirty-three patients were diagnosed with multiple myeloma (MM), and seven were in a reactive state. In PCST implementation, eight antibodies were used for staining, including anti-CD45-Pacific Blue, anti-CD19-PECy7, anti-CD138-OC515, anti-CD38-FITC, anti-CD56-PE, anti-β2-microglobulin-PerCPCy5.5, anti-kappa-APC, and anti-lambda-APC-C750. Plasma cells were initially identified using CD38 and CD138; thereafter, CD38+, CD138+ gated cells were analyzed for CD56, CD19, CD45, cytoplasmic kappa, cytoplasmic lambda, and β2-microglobulin. Conventional flow cytometry was performed with six monoclonal antibodies, including anti-CD56-FITC, anti-kappa-FITC, anti-CD19-PE, anti-lambda-PE, anti-CD138-PECy5, and anti-CD45-PECy7 (Beckman Coulter, USA). Monoclonal plasma cells with cytoplasmic light-chain restriction were detected in 30 of 33 (90.9%) MM cases by conventional methods, and 32 of 33 (97.0%) MM cases with the PCST method. No differences were noted between PCST and the conventional method in immunophenotyping and plasma cell percentages (P=0.323). Among plasma cells, levels (%) were significantly higher by the PCST approach than those in the conventional method (97.6% vs 95.8%, P=0.010). PCST exhibited better performance for plasma cell dyscrasias diagnosis, and could improve laboratory efficiency and quality.

A Case of Lymphoplasmacytic Lymphoma/Waldenström's Macroglobulinemia with IgM-κ and IgA-λ Biclonal Gammopathy

Lymphoplasmacytic lymphoma (LPL) is a low-grade B-cell neoplasm, composed of small B lymphocytes, plasmacytoid lymphocytes, and plasma cells, usually involving bone marrow and sometimes lymph nodes or spleen. LPL with bone marrow involvement and an IgM monoclonal gammopathy of any concentration is designated as Waldenström macroglobulinemia (WM). LPL associated with non-IgM monoclonal gammopathy or biclonal gammopathy is rarely observed. LPL diagnosis was based on clinical, morphological, and immunophenotypic findings. Recently, the test for L265P mutation of the myeloid differentiation factor 88 (MYD88) gene has been helpful in the diagnosis of LPL. Here, we reported the first case of LPL/WM with IgM-κ/IgA-λ biclonal gammopathy in Korea.

Evaluation of Time and Temperature Stability of Paroxysmal Nocturnal Hemoglobinuria Cells by Flow Cytometry

BACKGROUND: Flow cytometry analysis of paroxysmal nocturnal hemoglobinuria (PNH) is significantly affected by the methodology used. The lack of data on the effect of age and refrigeration on PNH clone stability motivated us to study these aspects using flow cytometry. METHODS: Peripheral blood was collected from six patients, of which two presented with PNH. All samples were tested immediately and stored at room temperature (RT, 20–25℃) and at 4℃ for re-analysis at 24, 48, 72 hr and 7 days. Anti-CD59-fluorescein isothiocyanate (Beckman Coulter, USA) and anti-CD235a-phycoerythrin (PE; Beckman Coulter) were used to stain red blood cells (RBCs). Fluorescein-labeled proaerolysin (Cedarlane, Canada), anti-CD15-PE (Beckman Coulter), anti-CD24-PE-cyanin 5 (Beckman Coulter), and anti-CD45-PE-cyanin 7 (Beckman Coulter) were used to stain granulocytes. Flow cytometry was performed using a FC500 flow cytometer (Beckman Coulter). The effects of time and temperature were analyzed using generalized estimating equations. RESULTS: No significant differences in the gated percentage of RBCs and PNH clone size of RBCs were observed between the RT and 4℃ groups up to 7 days of testing. The percentage of gated neutrophils decreased with specimen age (P<0.001) and a better correlation with baseline was obtained at 4℃ than at RT (P=0.014). Neutrophil PNH clones were stable until 48 hr and 72 hr at RT and 4℃, respectively, and could not be analyzed at 7 days. CONCLUSIONS: RBC analysis was successfully performed up to 7 days. For neutrophils, testing within 48 hr is recommended, because the number of gated cells decreases significantly with age.

Evaluation of the Triage TOX Drug Screen Assay for Detection of 11 Drugs of Abuse and Therapeutic Drugs

The demand for rapid and broad clinical toxicology screens is on the rise. Recently, a new rapid toxicology screening test, the Triage TOX Drug Screen (Alere Inc., USA), which can simultaneously detect 11 drugs of abuse and therapeutic drugs with an instrument-read cartridge, was developed. In the present study, we evaluated the efficacy of this new on-site immunoassay using 105 urine specimens; the results were compared with those obtained by using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-TMS). Precision was evaluated according to the CLSI EP12-A2 for analyte concentrations near the cutoff, including C₅₀ and±30% of C₅₀, for each drug using standard materials. The C₅₀ specimens yielded 35–65% positive results and the ±30% concentration range of all evaluated drugs encompassed the C₅–C₉₅ interval. The overall percent agreement of the Triage TOX Drug Screen was 92.4–100% compared with UPLC-TMS; however, the Triage TOX Drug Screen results showed some discordant cases including acetaminophen, amphetamine, benzodiazepine, opiates, and tricyclic antidepressants. The overall performance of the Triage TOX Drug Screen assay was comparable to that of UPLC-TMS for screening of drug intoxication in hospitals. This assay could constitute a useful screening method for drugs of abuse and therapeutic drugs in urine.

A novel BTK gene mutation, c.82delC (p.Arg28 Alafs*5), in a Korean family with X-linked agammaglobulinemia / 소아과

X-linked agammaglobulinemia (XLA) is a hereditary humoral immunodeficiency that results from Bruton’s tyrosine kinase (BTK) gene mutations. These mutations cause defects in B-cell development, resulting in the virtual absence of these lymphocytes from the peripheral circulation. Consequently, this absence leads to a profound deficiency of lg all isotypes, and an increased susceptibility to encapsulated bacterial infections. A 15-month-old Korean boy presented with recurrent sinusitis and otitis media after 6 months of age, and had a family history of 2 maternal uncles with XLA. Laboratory tests revealed a profound deficiency of Ig isotypes, and a decreased count of CD19⁺ B cells in the peripheral circulation. Based on his family history and our laboratory test results, he was diagnosed with XLA. We performed BTK gene analysis of peripheral blood samples obtained from family members to confirm the diagnosis. Mutational analysis revealed a novel hemizygous frameshift mutation (c.82delC, p.Arg28Alafs*5), in the BTK gene. His mother and maternal grandmother were heterozygous carriers of this mutation and his two maternal uncles were hemizygous at the same position. After XLA diagnosis, intravenous immunoglobulin (400 mg/kg, monthly) treatment was initiated; recurrent sinusitis and otitis media were subsequently brought under control. To our knowledge, this is the first reported case of a Korean pedigree with a novel mutation in the BTK gene.

Antimicrobial Activity of Medizyme-Plus, Developed for Cleansing Prior to Disinfection/Sterilization

OBJECTIVE: Disinfectants are essential for public health and environmental hygiene. The aim of this study was to investigate the in vitro antimicrobial activity of Medizyme-Plus (Soosan Co. Ltd., Seongnam, Korea) developed for cleansing prior to disinfection/ster-ilization, against bacteria and yeasts. METHODS: Clinical isolates were exposed to Medizyme-Plus (a product containing quaternary ammonium and a protease, amylase, and lipase) for various periods (0.5, 1, 2, 5, 10, 15, and 30 minutes). After exposure, the mixtures of isolates and Medizyme-Plus were inoculated into tryptic soy broths. To enumerate the surviving bacteria or yeasts, treated isolates were inoculated onto solid agar media (blood agar, MacConkey agar, and Sabouraud dextrose agar) and cultured at 35℃. RESULTS: All strains of bacteria and yeasts showed a 5-log10 reduction within 0.5 minutes of exposure to Medizyme-Plus. CONCLUSION: Medizyme-Plus can be used as a low-level disinfectant, in addition to cleanser, for hospital infection control. It will be necessary to perform disinfection/sterilization after cleansing with Medizyme-Plus.

Biocidal Effect of Hypochlorous Acid Solution, Neolox against Pathogenic Microorganisms

OBJECTIVE: Disinfection/sterilization of hospital devices prevents the occurrence of several infections; therefore, disinfectants are essential for public health. The purpose of this study was to evaluate the biocidal effect of a hypochlorous acid solution. METHODS: Hypochlorous acid solution, Neolox (Neo Chemical, Paju, Korea) obtained from Purester (Morinaga Engineering, Tokyo, Japan) was used. Antimicrobial activity of the solution against bacteria, yeasts, and mycobacteria at different exposure times (0.5, 1, 2, 5, 10, 15, and 30 minutes) was evaluated. RESULTS: All strains of bacteria and yeasts showed a 5-log10 reduction within 30 seconds of exposure to the solution, and mycobacteria showed the same reduction within 2 minutes. CONCLUSION: Hypochlorous acid solution has been widely used as a disinfectant in recent years. Neolox can be used as an effective intermediate- to high-level disinfectant for hospital infection control.

Efficiency of an Automated Reception and Turnaround Time Management System for the Phlebotomy Room

BACKGROUND: Recent advances in laboratory information systems have largely been focused on automation. However, the phlebotomy services have not been completely automated. To address this issue, we introduced an automated reception and turnaround time (TAT) management system, for the first time in Korea, whereby the patient's information is transmitted directly to the actual phlebotomy site and the TAT for each phlebotomy step can be monitored at a glance. METHODS: The GNT5 system (Energium Co., Ltd., Korea) was installed in June 2013. The automated reception and TAT management system has been in operation since February 2014. Integration of the automated reception machine with the GNT5 allowed for direct transmission of laboratory order information to the GNT5 without involving any manual reception step. We used the mean TAT from reception to actual phlebotomy as the parameter for evaluating the efficiency of our system. RESULTS: Mean TAT decreased from 5:45 min to 2:42 min after operationalization of the system. The mean number of patients in queue decreased from 2.9 to 1.0. Further, the number of cases taking more than five minutes from reception to phlebotomy, defined as the defect rate, decreased from 20.1% to 9.7%. CONCLUSIONS: The use of automated reception and TAT management system was associated with a decrease of overall TAT and an improved workflow at the phlebotomy room.

De novo Leukemic Variant of Mast Cell Leukemia With KIT D816V

No abstract available.

Activities of Quality Improvement for Blood Culture at a University Hospital / 대한임상미생물학회지

BACKGROUND: Blood culture is a critical test for diagnosing bloodstream infections. Frequent microbial contamination during sampling and testing leads to abuse of antimicrobial agents. We evaluated methods for reducing contamination and obtaining more reliable results. METHODS: We analyzed blood cultures obtained between 2009 and 2015. We established 6 quality indicators: true positive rate, contamination rate, blood sampling volume, number of sets of blood cultures, delayed transportation rate, and percentage of samples collected from the femoral region, with reference to the CLSI guideline M47-A, 2007. Education was provided for interns and nurses responsible for blood sampling and transportation of specimens, and data were analyzed monthly. RESULTS: At baseline, the true positive rate was 12.8%, and the contamination rate was 4.0%. During the intervention period, these were decreased to 10.9% and 1.9%, respectively. The percentage of samples smaller than 5 mL decreased from 29.7% to 2.7-11.3%. The rate of one set of blood cultures being ordered was always <5%. The delayed transportation rate decreased from 35.6% to 5.5-7.7%. Finally, the percentage of samples collected from the femoral region decreased from 41.5% to 22.0-31.0%, because of which we did not attain our goal, 20.8%. CONCLUSION: The results showed improvements in contamination rate, specimen volume, specimen transportation time, and the percentage of samples collected from the femoral region. The quality management of blood cultures in 2011 was comparatively poor, which led to increased contamination rate, large number of samples containing <5 mL of blood, and increased percentage of samples collected from the femoral region. Thus, quality improvement methods can produce more reliable results of blood cultures.

Comparison of Total and IgG ABO Antibody Titers in Healthy Individuals by Using Tube and Column Agglutination Techniques

BACKGROUND: Most immune reactions related to transfusion and transplantation are caused by IgM ABO antibodies. However, IgG also plays an important role in these reactions. Therefore, a method to measure antibodies, including IgG, is necessary. We investigated ABO antibody titers of healthy individuals using a column agglutination technique (CAT) with or without dithiothreitol (DTT) and compared them with titers obtained using a conventional tube method. METHODS: Among healthy adults who underwent a medical examination, 180 individuals (60 with blood group A, 60 with group B, and 60 with group O) were selected. Antibody titrations were performed using the immediate spin (IS) tube, anti-human globulin (AHG) tube, and CAT with or without DTT methods. RESULTS: Higher median values of anti-B and anti-A titers in groups A and B individuals, respectively, were obtained using the IS method than using the AHG method. Higher values for group O individuals were obtained using the AHG method. Higher median titers of anti-B and anti-A in group O individuals were obtained using CAT without DTT than using the AHG method. Median titers of anti-B and anti-A in all blood groups were higher in CAT without DTT than in CAT with DTT, especially for group O individuals. CONCLUSIONS: We recommend CAT with and without DTT for titration of anti-A and anti-B, especially in group O individuals, to provide more sensitive results that include IgG data. Adjustment of insurance coverage of fees associated with antibody titration might be necessary, considering the actual cost of reagents and personnel.

Evaluation of the OraQuick HCV Rapid Antibody Test as a Screening Test for Hepatitis C Virus Infection / 임상검사와정도관리

BACKGROUND: Among the multitude of tests developed for the diagnosis of hepatitis C virus (HCV) infection, the enzyme immunoassay and the chemiluminescence immunoassays (CLIA) are the most commonly used. The OraQuick HCV Rapid Antibody Test is also popular because it can detect HCV antibodies from blood or saliva within 20 minutes. In this study, we compared the performances of the OraQuick HCV Rapid Antibody Test and CLIA in the diagnosis of HCV infection. METHODS: We tested 150 serum samples from Soonchunhyang University Seoul Hospital for HCV between November 2012 and January 2013 using CLIA (ADVIA Centaur) as well as the OraQuick test. The data from both tests were compared to the results of HCV real-time PCR (COBAS AmpliPrep/COBAS TaqMan HCV test kit). RESULTS: In the PCR analysis, 59 of the 150 samples (39.3%) tested positive and 91 (60.7%) tested negative for HCV RNA. All these samples also tested positive when screened by CLIA. However, only 57 of 59 samples tested positive with the OraQuick test. Among the 91 samples found to be HCV-negative in the PCR analysis, 50 tested negative in both CLIA and the OraQuick tests. However, a discrepancy was noted among the remaining 41 samples that tested HCV-negative in the PCR analysis; 21 of these samples tested positive in both CLIA and the OraQuick tests, but the remaining 20 tested positive only in CLIA. CONCLUSIONS: Although the OraQuick test showed a marginally lower sensitivity for HCV detection than CLIA, we conclude that it is still beneficial because it is rapid and can be performed using blood and saliva samples. Our findings suggest that the OraQuick test could be an important diagnostic tool for screening HCV infection.

Comparison of Ogawa Media, BACTEC MGIT 960 System and TB/NTM Real-Time PCR for Detecting Mycobacterium Species / 결핵및호흡기질환

BACKGROUND: Mycobacterial infection is a problem throughout the world along with the increase of immunocompromised patients. For this reason, there have been many methods for faster and more accurate diagnosis. In this study, we evaluated several laboratory methods for mycobacterial infection. METHODS: From January to December 2009, 635 specimens were cultured with mycobacteria growth indicator tube (MGIT) and Ogawa media. Polymerase chain reaction (PCR) was performed with the AdvanSure tuberculosis (TB)/non-tuberculosis mycobacterium (NTM) real-time PCR Kit (LG Life Sciences, Seoul, Korea). The 69 samples showing positive culture results were identified with the AdvanSure Mycobacteria Genotyping Chip Kit (LG Life Science, Seoul, Korea). RESULTS: Sixty-nine (10.9%) out of 635 samples showed positive results for mycobacterial culture. Among the 635 samples, 64 were positive in MGIT, but only 42 were positive in Ogawa media. Of the 635 samples, 607 (95.6%) showed the same results between MGIT and Ogawa and the results of 579 (95.4%) were also consistent with the TB/NTM real-time PCR results. However, in the case of NTM, only one (1/24, 4.2%) was positive in PCR. In the Mycobacteria genotyping chip analysis, the most frequently identified NTM species in descending order were M. avium, M. intracellulare, M. chelonae and M. abscessus. CONCLUSION: Culturing with a combination of MGIT and Ogawa is recommended to increase the recovery rate of mycobacteria. Although PCR missed a reasonable number of NTM, it is faster and usually gives results that concur with those from the culture. The appropriate combination of diagnostic methods with clinical correlation are necessary.

Comparison of SD BIOLINE Rapid Influenza Antigen Test Using Two Different Specimens, Nasopharyngeal Swabs and Nasopharyngeal Aspirates / 대한임상미생물학회지

BACKGROUND: The pandemic swine origin influenza A/H1N1 2009 virus (H1N1 2009) was rapidly spread out all over the world after it was first found in April, 2009. This study was made to compare the performance of nasopharyngeal swabs and nasopharyngeal aspirates for the SD Bioline rapid influenza antigen test. METHODS: From Aug to Nov, 2009 the SD Bioline rapid influenza antigen tests were conducted with the nasopharyngeal swabs and the nasopharyngeal aspirates from the 244 specimens of patients who had come to the hospital with influenza-like illness. The data from the examination were compared with the multiplex RT-PCR as a reference standard to obtain sensitivity, specificity, positive predictive value and negative predictive value. RESULTS: The sensitivity and the specificity of the SD Bioline rapid influenza antigen tests with the nasopharyngeal swabs were 75.8%, and 93.3% respectively, and the sensitivity and specificity with the nasopharyngeal aspirates were 61.3%, and 98.3% respectively. CONCLUSION: Even if the nasopharyngeal aspirates showed the lower sensitivity than the nasopharyngeal swabs, since the specificity is higher, the nasopharyngeal aspirates are more useful because we can reduce false positive rate.