The Application Value of the D-Dimer Critical Value in Diagnosing Deep Vein Thrombosis in Patients with Bone Trauma.

BACKGROUND: D-dimer is used as a clinical indicator to predict venous thromboembolism, and some hospitals have included it in the critical value project. We aimed to evaluate whether the setting of a D-dimer critical value is helpful in the diagnosis of deep vein thrombosis in patients with bone trauma and to explore the rationality of setting a D-dimer critical value limit. METHODS: The clinical data of 4,897 bone trauma patients, hospitalized from April 1, 2022, to March 31, 2023, were retrospectively analyzed. Our hospital set the critical value limit for when the D-dimer value was greater than 15.0 mg/L, and Bayesian model was used to evaluate the relationship between deep vein thrombosis and the D-dimer limit. RESULTS: During this period, 199 times the D-dimer detection value was greater than 15.0 mg/L, and the critical value was reported and accounted for 4.06%. The predicted probability of lower limb venous thrombosis in patients who triggered the critical value of D-dimer was 40.21%, and the actual incidence was 34.67%. There were 376 patients with lower limb venous thrombosis during hospitalization, and 81.38% of the D-dimer value did not reach the critical value limit. CONCLUSIONS: The role of D-dimer as a critical value item in predicting DVT in patients with orthopedic trauma is small. Whether to list D-dimer as a critical value item can be comprehensively considered according to the own situation of medical institutions and the recommendations of clinicians. The same can be applied for the setting of critical value boundaries.

A Case of False Decrease of Plasma D-Dimer.

BACKGROUND: D-dimer, a specific product of cross-linked fibrin degradation, is of great clinical value in the early diagnosis of thrombotic diseases and in monitoring the efficacy of thrombolysis; therefore, the accuracy of D-dimer test results is crucial. METHODS: This article reports a case of a patient with disseminated intravascular coagulation (DIC) who experienced a false decrease in D-dimer due to the hook effect. RESULTS: The three D-dimer test results for DIC patients were 1.09 mg/L, 0.93 mg/L, and 1.43 mg/L. After sample dilution, the results were: first time (1:128) 842.24 mg/L, second time (1:128) 1,505.28 mg/L, third time (1:32) 415.68 mg/L. There was a significant difference in the three test results before and after dilution, because the D-dimer concentration was too high, exceeding the detection range and causing the hook effect, which falsely lowered the D-dimer value. CONCLUSIONS: When the D-dimer value of DIC patients does not match the clinical situation, the possibility of the hook effect should be considered, and the false decrease can be ruled out by the sample dilution method. In this way, accurate clinical results can be obtained to avoid delaying the diagnosis and treatment of DIC patients.

The Variation of RhD Blood Group in Different Periods in a Patient with Systemic Lupus Erythematosus.

BACKGROUND: Autoimmune hemolytic anemia disease often produces a large number of various autoantibodies, and some autoantibodies may be related to Rh blood group. In rare cases, autoantibodies can specifically target Rh antigen, thus interfering with the identification of Rh blood group. METHODS: A case of systemic lupus erythematosus (SLE) with inconsistent RhD blood group identification results in different periods was reported and the reasons were analyzed. RESULTS: Some autoantibodies can completely block D antigen on red blood cells, resulting in no redundant D sites on red blood cells binding to reagent anti D. In addition, the immunity of the body is extremely low, and the expression of red blood cell blood group antigens in part of the body is inhibited, which will cause the weakening of the expression of Rh antigen in red blood cells. Therefore, when testing the RhD blood type of the patient, the reagent anti D does not agglutinate with the patient's red blood cells, and a false negative result of the initial screening appears. Through the RhD negative confirmation test, the patient's blood type is a serologically weak D phenotype. CONCLUSIONS: If the result of serological preliminary screening test is RhD negative or RhD variant, the recipient should be treated as RhD negative, and RhD negative red blood cells should be transfused during blood transfusion. Conditional laboratories can implement RHD genotyping, which is conducive to improving the precise blood transfusion management level of RhD negative blood recipients, saving rare blood resources and improving the treatment efficiency of patients.

A case of Pseudo-Lowering of Blood Routine Results caused by Improper Blood Collection Operation.

BACKGROUND: Unqualified samples directly affect the accuracy of laboratory test results. Some links in the preanalysis stage are prone to produce unqualified samples that are difficult to identify, leading to inaccurate test results and affecting clinical diagnosis and treatment. METHODS: This paper reports a case of pseudo-lowering of blood routine results caused by improper blood collection operation. RESULTS: The blood routine samples caused by improper blood collection operation by nurses were diluted by the sealing solution of the indwelling needle, which resulted in inaccurate test results. CONCLUSIONS: The laboratory should pay attention to the quality control in the preanalysis stage and identify unqualified samples in time, provide reliable diagnostic basis for clinical practice, and avoid the occurrence of adverse events.

Spurious Platelet Counts Due to Cell Fragmentation in a Patient with Influenza B Virus.

BACKGROUND: In clinical practice, thrombocytopenia is very dangerous for patients, because it has the risk of bleeding and may cause serious adverse consequences. Therefore, timely and accurate identification of spurious platelet counts is very important to improve patient safety. METHODS: This study reported a case of spurious platelet counts in a patient with influenza B virus. RESULTS: Leukocyte fragmentation is responsible for the inaccurate platelet detection results by resistance method in this influenza B patient. CONCLUSIONS: In practical work, if abnormalities are found, blood smear staining and microscopic examination should be carried out in time, and clinical data should be combined to avoid the occurrence of adverse events and ensure patient safety.

A Case of Abnormal Results Caused by Urine Contamination in Serum During Detection.

BACKGROUND: Unqualified samples directly affect the accuracy of test results in clinical laboratory. Timely and accurate identification of unqualified specimens can avoid the occurrence of medical adverse events. METHODS: This study reported a case of abnormal results caused by urine carrying contamination in serum during detection. RESULTS: During the testing process, improper operation of laboratory staff led to serum contamination with urine, which affected the accuracy of the test results. CONCLUSIONS: In addition to the pre-inspection stage, all laboratories should also pay attention to the quality control of sample during the inspection, so as to ensure the accuracy of the results and medical safety.