Accurate Point-of-Care Detection of Ruptured Fetal Membranes: Improved Diagnostic Performance Characteristics with a Monoclonal/Polyclonal Immunoassay.

OBJECTIVE: Accurate and timely diagnosis of rupture of membranes (ROM) is imperative to allow for gestational age-specific interventions. This study compared the diagnostic performance characteristics between two methods used for the detection of ROM as measured in the same patient. METHODS: Vaginal secretions were evaluated using the conventional fern test as well as a point-of-care monoclonal/polyclonal immunoassay test (ROM Plus(®)) in 75 pregnant patients who presented to labor and delivery with complaints of leaking amniotic fluid. Both tests were compared to analytical confirmation of ROM using three external laboratory tests. Diagnostic performance characteristics were calculated including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. RESULTS: Diagnostic performance characteristics uniformly favored ROM detection using the immunoassay test compared to the fern test: sensitivity (100% vs. 77.8%), specificity (94.8% vs. 79.3%), PPV (75% vs. 36.8%), NPV (100% vs. 95.8%), and accuracy (95.5% vs. 79.1%). CONCLUSIONS: The point-of-care immunoassay test provides improved diagnostic accuracy for the detection of ROM compared to fern testing. It has the potential of improving patient management decisions, thereby minimizing serious complications and perinatal morbidity.

Establishing benchmarks and metrics for disruptive technologies, inappropriate and obsolete tests in the clinical laboratory.

Benchmarks and metrics related to laboratory test utilization are based on evidence-based medical literature that may suffer from a positive publication bias. Guidelines are only as good as the data reviewed to create them. Disruptive technologies require time for appropriate use to be established before utilization review will be meaningful. Metrics include monitoring the use of obsolete tests and the inappropriate use of lab tests. Test utilization by clients in a hospital outreach program can be used to monitor the impact of new clients on lab workload. A multi-disciplinary laboratory utilization committee is the most effective tool for modifying bad habits, and reviewing and approving new tests for the lab formulary or by sending them out to a reference lab.

Automated assays for sVEGF R1 and PlGF as an aid in the diagnosis of preterm preeclampsia: a prospective clinical study.

OBJECTIVE: The purpose of this study was to assess the utility of soluble vascular endothelial growth factor 1 (sVEGF R1) and placental growth factor (PlGF) levels in the clinical diagnosis of preeclampsia. STUDY DESIGN: Plasma was collected prospectively from 457 subjects (n = 409 without preeclampsia, n = 48 with preeclampsia) at 20-36 weeks' gestation. Automated immunoassays were used to measure free sVEGF R1 and free PlGF. RESULTS: Clinical sensitivities of 0.96 and specificities of 0.96 and 0.95 were calculated for sVEGF R1 and PlGF, respectively, for aiding in the diagnosis of preeclampsia. Among subjects with chronic hypertension, sVEGFR1 was dramatically elevated and PlGF decreased in those with superimposed preeclampsia (P < .001 for superimposed preeclampsia vs chronic hypertension for both biomarkers). The ratio of sVEGFR1/PlGF provided a better test to aid in the diagnosis of preeclampsia than either analyte alone (3% false positive rate). CONCLUSION: Free sVEGF R1 and PlGF were useful in differentiating women with preterm preeclampsia from normotensive and hypertensive subjects.

Secretion of a TNFR:Fc fusion protein following pulmonary administration of pseudotyped adeno-associated virus vectors.

This study evaluated and compared delivery of the tumor necrosis factor alpha receptor (TNFR)-immunoglobulin G1 (IgG1) Fc fusion (TNFR:Fc) gene to the lung by single and repeat administrations of multiple pseudotyped adeno-associated virus (AAV) vectors as a means for achieving systemic distribution of the soluble TNFR:Fc protein. A single endotracheal administration of AAV[2/5]cytomegalovirus (CMV)-TNFR:Fc vector (containing the AAV2 inverted terminal repeats and AAV5 capsid) to the rat lung resulted in long-term, high levels of serum TNFR:Fc protein that gradually declined over a period of 8 months. Endotracheal delivery of AAV[2/1]CMV-TNFR:Fc resulted in serum TNFR:Fc protein levels that were detectable for at least 4 months but were 10-fold lower than that of the AAV[2/5] vector. In contrast, secretion of the TNFR:Fc protein following pulmonary delivery of AAV[2/2]CMV-TNFR:Fc vector was very inefficient, and the protein was detected in the blood only when an airway epithelial cell-specific promoter, CC10, was substituted for the CMV enhancer/promoter to control transgene expression. In the context of AAV[2/5], the CC10 promoter was as efficient as CMV enhancer/promoter in generating similar levels of systemic TNFR:Fc protein, suggesting that this protein is secreted primarily from the airway epithelium. In mice, comparable long-term secretion of TNFR:Fc protein was demonstrated after AAV[2/2] and AAV[2/5] delivery, although the kinetics of transduction appeared to be different. All pseudotyped AAV vectors elicited serum anti-AAV capsid-neutralizing antibody responses, but these did not prevent lung transduction and efficient secretion of TNFR:Fc protein to the circulation following readministration with AAV[2/5]. These results highlight the potential utility of AAV vectors containing serotype 5 capsid to deliver and redeliver genes of secreted proteins to the lung to achieve long-term systemic protein expression.