Tae Youn Choi

Utility of D-dimer Assay for Diagnosing Pulmonary Embolism: Single Institute Study

BACKGROUNDnPulmonary embolism (PE) presents with diverse non-specific signs and symptoms and its diagnosis mainly depends on diagnostic imaging tests which are laborious and not cost-effective, and only a small proportion of patients with suspected PE actually have the disease. The aim of this study was to analyze the utility of D-dimer test for diagnosing PE by categorizing patients into PE likely and PE unlikely groups using Wells score for clinical probability.nnnMETHODSnOne hundred forty consecutive patients with clinically suspected PE, in whom D-dimer and imaging tests were performed were enrolled. Dignosis of PE was made when the imaging tests were positive. Wells scores were retrospectively assigned and the dignostic utility of D-dimer test was analyzed.nnnRESULTSnOf the 140 patients studied, D-dimer test was positive in 97 and diagnostic imaging tests revealed PE, deep vein thrombosis (DVT), and PE+DVT in 24, 3, and 7 patients, respectively. For the diagnosis of PE, D-dimer test with cutoff value of > or =230 ng/mL showed sensitivity, specificity, and negative predictive value of 96.8%, 39.6%, and 97.7%, respectively. These values were 96.3%, 37.9%, and 91.7% in PE likely group (n=56), and 100%, 38.8%, and 100% in PE unlikely group (n=84). Among 43 patients with D-dimer values of <230 ng/mL, only one patient was diagnosed with PE, who belonged to the PE likely group.nnnCONCLUSIONSnD-dimer test cannot be used as a stand-alone test to diagnose PE, but it can be helpful for exclusion of PE especially in PE unlikely group according to Wells score.

Activities of Quality Improvement for Blood Culture at a University Hospital

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 2.711.3%. 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. (Ann Clin Microbiol 2015;18:88-93)

De novo Leukemic Variant of Mast Cell Leukemia With KIT D816V

Mast cell leukemia (MCL), a highly aggressive form of systemic mastocytosis, accounts for less than 1% of all cases [1]. It is diagnosed on the basis of the criteria for systemic mastocytosis proposed by the WHO and the presence of at least 20% atypical mast cells of all bone marrow (BM) cells [2]. Here, we present a case of de novo leukemic variant of MCL with KIT D816V; to our knowledge, this is the first report of de novo leukemic variant of MCL in Korea.

Evaluation of OraQuick Advance Rapid HIV-1/2 Antibody Test as a Screening Test for HIV Infection

Background: For the diagnosis of HIV infection, enzyme immunoassay (EIA) or chemiluminescence immunoassay (CLIA) is commonly used as a screening test. Although these methods have a high sensitivity and low cost, their high false positive rate can cause confusion in the patients and clinicians until a more specific test is done. OraQuick Advance Rapid HIV-1/2 Antibody Test (OraQuick) (OraSure Technologies, USA) is a rapid test that can detect HIV-1/2 antibodies in 20 minutes. It uses oral fluid, whole blood or serum sample. In this study, we evaluated the usefulness of the OraQuick as a screening and point-of-care test for HIV infection. Methods: From Jan 2007 to Dec 2008, 45,276 samples referred to our laboratory were tested by CLIA method using the ADVIA Centaur (Bayer Healthcare LTD., USA) for HIV-1/2 antibody detection. Among them, 74 positive and 50 negative samples were tested by the Western immunoblot assay (WIB) and OraQuick test as a case-control study. Also, oral fluids from 30 HIV patients and 48 healthy persons were tested by OraQuick test. Results: The sensitivity and specificity of OraQuick test (using serum samples) were 100% and 98.8% (95% confidence interval 96.9∼100%), respectively. OraQuick tests (using oral fluid samples) were all positive for HIV patients but all negative for healthy persons. Conclusion: This study suggests that OraQuick can be used successfully as a rapid test for the early detection of HIV-1/2 antibody in patients visiting emergency departments and for the prevention of HIV infection in the health care providers. (Korean J Clin Microbiol 2009;12:116-121)