Urinalysis: diagnostic performance of urine dipstick compared to an automated microscopic method

Introduction: Urinalysis is one of the most important clinical laboratory tests because numerous pathologies can manifest or be suspected through this test. Although the previous reports mention that urinary microscopy is a fundamental part of urinalysis for diagnostic support of various conditions, there is a debate about the utility of this test section in a certain patient population. The aim of this study was to determine the diagnostic performance of the urinary dipstick analysis and the potential risks of false-negative (FN) results. Material and methods: This is a retrospective and observational study, and urinalysis information was obtained from non-hospitalized patients. The dipstick and microscopic analyses were performed using the Clinitek-ATLAS (index test) and iQ200-SPRINT (reference standard) devices. Dipstick or microscopy analyses were positive if ≥ 1 parameters were abnormal. A Bayesian hierarchal beta-binomial model was carried out for each performance parameter. Risk analysis was performed as proposed in the literature. Results: Five hundred and fifty-two patients were included in the study. The posterior median at group level was 94% (credible interval 95% [CrI 95%] 89.9-97%) for sensitivity (Se), 57.1% (CrI 95%, 50.1-64.1%) for specificity, and 5.8% (CrI 95%, 2.59-9.64%) for FN rate (FNR). The posterior probability Se > 90% was 95.9% at a group level. The risk analysis found only low-risk false-negative events. Conclusions: The performance of the dipstick analysis was appropriate, with a good certainty of Se > 90% and a FNR < 10% at the operator level. Omission of microscopic analysis can be a safe action in a patient with a negative dipstick since FNs with a clinical impact are not expected

Probability of a successful platelet dose according to the number of platelet concentrates

Introduction: Platelet transfusion for prophylactic or therapeutic purposes is a common practice. The outcome evaluated in using platelets for prophylactic purposes has been preventing clinically significant bleeding. Transfusion guidelines recommend using platelet transfusion for prophylactic purposes based on the clinical scenario and a peripheral blood platelet threshold. Methods: A retrospective study was carried out, with the platelet count of the registry of quality control of platelet concentrates (PC), obtaining a total of 100. Age, sex, blood group, and peripheral blood platelets were compared with donors not included in quality control. The sum of the platelet count of all possible combinations of the 100 PCs was obtained for the 2-3 PCs scenarios and the 4-8 PCs scenarios, a simulation of 1,000,000 iterations with random sampling without replacement and the sum of the platelet count of the combinations obtained was performed. The proportion of successful doses in the distribution was obtained according to the number of PCs. Results: No statistically significant difference was found between donors included in quality control and those not included. The probability of administering a dose of ≥ 1.5 × 10^11 platelets is 97.33% and 99.99% for 3-4 PCs, respectively. Conclusions: This study may be useful for the physician who indicates PC for prophylactic purposes, using an appropriate number of PCs, and optimizing the available inventory

Urinalysis: diagnostic performance of urine dipstick compared to an automated microscopic method

Introduction: Urinalysis is one of the most important clinical laboratory tests because numerous pathologies can manifest or be suspected through this test. Although the previous reports mention that urinary microscopy is a fundamental part of urinalysis for diagnostic support of various conditions, there is a debate about the utility of this test section in a certain patient population. The aim of this study was to determine the diagnostic performance of the urinary dipstick analysis and the potential risks of false-negative (FN) results. Material and methods: This is a retrospective and observational study, and urinalysis information was obtained from non-hospitalized patients. The dipstick and microscopic analyses were performed using the Clinitek-ATLAS (index test) and iQ200-SPRINT (reference standard) devices. Dipstick or microscopy analyses were positive if ≥ 1 parameters were abnormal. A Bayesian hierarchal beta-binomial model was carried out for each performance parameter. Risk analysis was performed as proposed in the literature. Results: Five hundred and fifty-two patients were included in the study. The posterior median at group level was 94% (credible interval 95% [CrI 95%] 89.9-97%) for sensitivity (Se), 57.1% (CrI 95%, 50.1-64.1%) for specificity, and 5.8% (CrI 95%, 2.59-9.64%) for FN rate (FNR). The posterior probability Se > 90% was 95.9% at a group level. The risk analysis found only low-risk false-negative events. Conclusions: The performance of the dipstick analysis was appropriate, with a good certainty of Se > 90% and a FNR < 10% at the operator level. Omission of microscopic analysis can be a safe action in a patient with a negative dipstick since FNs with a clinical impact are not expected