The current state of practice in the diagnosis of venous thromboembolism at an academic medical center

The limited clinical utility of a routine creatine kinase (CK) on admission to a psychiatric inpatient unit

BACKGROUND

Creatine kinase (CK) is an intracellular enzyme expressed most commonly in tissues such as skeletal muscle. CK can be used as an investigation to support the diagnosis of conditions such as neuroleptic malignant syndrome (NMS), a rare idiosyncratic drug reaction - classically to antipsychotic medications - which can be fatal. Routine screening of CK in psychiatric inpatients is a known practice, but its value is uncertain. We aimed to ascertain whether such screening resulted in new diagnoses of NMS or other conditions, and changes in clinical management.

METHODS

Using an electronic case register, we conducted a descriptive retrospective cohort study, identifying all psychiatric inpatient admissions in a South London mental health trust over a four-year period where a CK test was conducted within 48 h of admission. We extracted the demographic and clinical characteristics (e.g., diagnosis) of those who met inclusion criteria. Free-text review was performed on all those with a CK potentially suggestive of NMS (CK ≥ 4x upper limit of normal reference range (ULN)) to determine the impact of this abnormal result on subsequent management and diagnosis (including NMS if identified).

RESULTS

Of 14,236 inpatient episodes in the specified window, 2358 (16.6%) had a CK test within 48 h of admission. This was ≥ 4x ULN in 327 (13.8%) cases (free-text successfully reviewed in 318). There were no cases of NMS identified. An abnormal CK result led to a new alternative diagnosis, such as dehydration or catatonia, in only 14 patients (4.4% raised CK sample, 0.6% total CK sample). Impact on subsequent management appeared limited, with the most common adjustment being an increase in frequency of physical observations in 47 instances (14.8%).

CONCLUSIONS

The clinical utility of untargeted screening using a serum CK for psychiatric inpatients appears limited, with poor specificity in detection of NMS and a minimal impact on subsequent clinical management.

The predictive value of platelet to lymphocyte ratio and D-dimer to fibrinogen ratio combined with WELLS score on lower extremity deep vein thrombosis in young patients with cerebral hemorrhage

OBJECTIVE

To study the predictive effect on YCH patients complicated with LEDVT by PLR and DFR combined with WELLS score.

MATERIALS AND METHODS

A total of 109 patients with YCH were selected as the research subjects. Patients with combined LEDVT were in the thrombosis group (33 cases), and without LEDVT in the non-thrombosis group (76 cases). Wells score was used to evaluate the vascular of the lower extremities. The PLR and DFR were calculated. The diagnostic value of PLR and DFR combined with the Wells score was evaluated by the AUC, sensitivity, specificity, and other indicators in the ROC.

RESULTS

The values of PLR, DFR, and Wells score in the thrombus group were 149.20 ± 52.17, 118.46 ± 8.37, and 2.67 ± 0.48, and that of the non-thrombotic group were 95.27 ± 29.48, 75.28 ± 10.16, and 0.72 ± 0.34, respectively. The differences were statistically significant. ROC results showed good diagnosis power of PLR (sensitivity 86.35%, specificity 75.18%, AUC 0.702.), DFR (sensitivity 88.57%, specificity 79.21%, AUC 0.786.), and the Wells score (sensitivity 90.17%, specificity 81.06%, AUC 0.889.). The combined application of the Wells score, PLR, and DFR for the occurrence of LEDVT had a sensitivity of 97.65%, a specificity of 92.43%, a missed diagnosis rate of 2.35%, and a misdiagnosis rate of 7.57%. The area under the ROC curve was 0.951, which was higher than using these variables independently.

CONCLUSIONS

PLR and DFR combined with Wells score have high specificity for predicting LEDVT in YCH patients with low missed diagnosis and low misdiagnosis rates. They are worthy of popularization and application.

Diagnostic value of platelet-derived microparticles in pulmonary thromboembolism: A population-based study

An early and accurate diagnosis of pulmonary thromboembolism (PTE) remains challenging. The present study aimed to evaluate the diagnostic value of platelet-derived microparticles in PTE based on a population study. A total of 102 patients with PTE, 102 healthy controls and 40 patients suspected with PTE were enrolled in this study. The platelet count, mean platelet volume and platelet distribution width were assessed using an automated hematology analyzer, P-selectin was assessed using an ELISA kit and PMPs were explored using flow cytometry using Megamix beads. Receiver operating characteristic curves were established to evaluate the diagnostic values of PMPs, D-dimer, PMPs combined with D-dimer, and multiple parameters (including PMPs, platelet distribution width, P-selectin and D-dimer in PTE). The PMP levels were significantly higher in the patients with PTE (609.10/µl) compared with those in the healthy controls (230.60/µl) and patients with suspicious PTE (166.70/µl; P<0.01). The accuracy (72.06%) of PMPs in the diagnosis of PTE was similar to those of D-dimer (P>0.05). The combination of D-dimer and PMPs significantly increased the sensitivity (86.27%) of D-dimer and the specificity of PMP for the diagnosis of PTE (P<0.01). The combination of PMPs, platelet distribution width, P-selectin and D-dimer exhibited high sensitivity (88.24%), specificity (91.18%) and accuracy (89.71%) in the diagnosis of PTE. These findings suggest that elevated PMP levels are an effective predictor of PTE. The combination of PMPs, platelet distribution width, P-selectin and D-dimer may be used in the diagnosis of PTE with high sensitivity and specificity.

The role of laboratory in ensuring appropriate test requests

This review highlights the role of laboratory professionals and the strategies to be promoted in strict cooperation with clinicians for auditing, monitoring and improving the appropriateness of test request. The introduction of local pathways and care maps in agreement with international and national guidelines as well as the implementation of reflex testing and algorithms have a central role in guiding test request and in correcting the overuse/misuse of tests. Furthermore, removing obsolete tests from laboratory menu and vetting of restricted tests is recommended to increase cost-effectiveness. This saves costs and permits to introduce new biomarkers with increased diagnostic accuracy with a better impact on patient outcome. An additional issue is concerning the periodicity of (re)testing, accounting that only a minority of tests may be ordered as often as necessary. In the majority of cases, a minimum retesting interval should be introduced. The availability of effective computerised order entry systems is relevant in ensuring appropriate test requests and in providing an aid by automated rules that may stop inappropriate requests before they reach the laboratory.

Diagnostic biomarkers in venous thromboembolic disease

OBJECTIVE

Venous thromboembolism (VTE) is a common disease with serious, often fatal sequelae. The optimal strategy for diagnosis of VTE remains unclear, although considerable progress has been made in this area. Several new biomarkers have showed promise for diagnosis of VTE, and more are under active investigation. We reviewed the literature for studies evaluating these diagnostic biomarkers.

METHODS

We reviewed the English literature between 1990 and 2015, searching for papers evaluating diagnostic performance of biomarkers in VTE.

RESULTS

D-dimer, a fibrin degradation product, has been thoroughly investigated, and performs well in select populations, although it is best as a rule-out test because of its generally low specificity. Soluble P-selectin, a marker of endothelial activation, has shown good diagnostic performance in several studies but has not yet been adopted widely. Others, including cellular adhesion molecules, tissue factor, circulating microparticles, and C-reactive protein, are under investigation, with varying results in a few studies.

CONCLUSIONS

At this time, D-dimer and P-selectin remain the most clinically valuable. New biomarkers are needed for clinical use in VTE.

Effectiveness of d-dimer as a screening test for venous thromboembolism: an update

Venous thromboembolism (VTE) is the leading cause of morbidity and mortality among hospitalized patients. We searched the PubMed database and reviewed the articles published until June 2011. Articles related to the D-dimer and VTE were considered to write this paper. Many factors play a key role in changing the sensitivity and specificity of D-dimer testing, including the extent of thrombosis and fibrinolytic activity, duration of symptoms, anticoagulant therapy, comorbidity due to surgical or medical illnesses, inflammatory diseases, cancer, elderly age, pregnancy and the postpartum period, and previous VTE. Many previous studies have shown that the D-dimer test is highly sensitive (>95%) in acute deep venous thrombosis or pulmonary embolism, usually with a cut-off value of 500 μg FEU/l, which reasonably rules out acute VTE, particularly in patients with low clinical probability (LCP) or intermediate clinical probability. Patients with high D-dimer levels upon presentation may prompt a more intense diagnostic approach, irrespective of pretest probability. Studies performed after a negative D-dimer for 3 months proved the high negative predictive value (NPV) of D-dimer testing together with LCP in patients with suspected VTE. Among oncology patients, D-dimer testing has the highest sensitivity and NPV in excluding VTE. The new cutoff values of D-dimer testing were analyzed in a recent prospective study of pregnant women; they are 286 ng DDU/ml, 457 ng DDU/ml, and 644 ng DDU/ml for the first, second, and third trimesters, respectively.

The landscape of inappropriate laboratory testing: a 15-year meta-analysis

BACKGROUND

Laboratory testing is the single highest-volume medical activity and drives clinical decision-making across medicine. However, the overall landscape of inappropriate testing, which is thought to be dominated by repeat testing, is unclear. Systematic differences in initial vs. repeat testing, measurement criteria, and other factors would suggest new priorities for improving laboratory testing.

METHODS

A multi-database systematic review was performed on published studies from 1997-2012 using strict inclusion and exclusion criteria. Over- vs. underutilization, initial vs. repeat testing, low- vs. high-volume testing, subjective vs. objective appropriateness criteria, and restrictive vs. permissive appropriateness criteria, among other factors, were assessed.

RESULTS

Overall mean rates of over- and underutilization were 20.6% (95% CI 16.2-24.9%) and 44.8% (95% CI 33.8-55.8%). Overutilization during initial testing (43.9%; 95% CI 35.4-52.5%) was six times higher than during repeat testing (7.4%; 95% CI 2.5-12.3%; P for stratum difference <0.001). Overutilization of low-volume tests (32.2%; 95% CI 25.0-39.4%) was three times that of high-volume tests (10.2%; 95% CI 2.6-17.7%; P<0.001). Overutilization measured according to restrictive criteria (44.2%; 95% CI 36.8-51.6%) was three times higher than for permissive criteria (12.0%; 95% CI 8.0-16.0%; P<0.001). Overutilization measured using subjective criteria (29.0%; 95% CI 21.9-36.1%) was nearly twice as high as for objective criteria (16.1%; 95% CI 11.0-21.2%; P = 0.004). Together, these factors explained over half (54%) of the overall variability in overutilization. There were no statistically significant differences between studies from the United States vs. elsewhere (P = 0.38) or among chemistry, hematology, microbiology, and molecular tests (P = 0.05-0.65) and no robust statistically significant trends over time.

CONCLUSIONS

The landscape of overutilization varies systematically by clinical setting (initial vs. repeat), test volume, and measurement criteria. Underutilization is also widespread, but understudied. Expanding the current focus on reducing repeat testing to include ordering the right test during initial evaluation may lead to fewer errors and better care.