Urinary Neutrophil Gelatinase-Associated Lipocalin Predicts Intensive Care Unit Admission Diagnosis: A Prospective Cohort Study.

Background: Acute kidney injury (AKI) is most commonly caused by tubular injury and is associated with a wide variety of critical illnesses. It is well known that urinary biomarkers can lead to the early identification of AKI. However, the ability of urinary biomarkers to distinguish between different types of critical illness has been less studied. Methods: In this prospective cohort study, urinary neutrophil gelatinase-associated lipocalin (uNGAL) was measured in 107 patients consecutively admitted to the ICUs in our tertiary medical center. uNGAL samples were collected within 3-6 hours of admission to an ICU and measured by ELISA. All data were analyzed using R statistical software, and univariate analysis was used to determine the correlations of uNGAL levels with AKI stage, admission diagnoses, and ICU course. Results: uNGAL level increased by a mean of 24-fold (SD 10-59) in ICU patients with AKI and demonstrated a significant correlation with the different AKI stages. uNGAL predicted the need for RRT, with values increased by more than 15-fold (P<0.05) in patients needing RRT, and remained a useful tool to predict AKI in ICU patients with a urinary tract infection. uNGAL level was correlated with certain ICU admitting diagnoses whereby uNGAL levels were lower in ICU patients with cardiogenic shock compared with other admission diagnoses (ß=-1.92, P<0.05). Conclusions: uNGAL can be used as an early predictor of AKI and its severity in patients admitted to the ICU, including the need for RRT. uNGAL may also help in distinguishing patients with cardiogenic shock from those with other critical illnesses and identifying those at risk for poor outcomes irrespective of the presence of AKI.

Validation study of the Access antimüllerian hormone assay for the prediction of poor ovarian response to controlled ovarian stimulation.

OBJECTIVE: To evaluate the diagnostic performance of the antimüllerian hormone (AMH) level determined using the Access AMH assay for predicting poor ovarian response (POR) defined as ≤4 oocytes retrieved, including the validation of the predefined AMH cutoff of 0.93 ng/mL in both serum and plasma. DESIGN: Prospective cohort study. SETTING: Fifteen private and academic fertility centers (14 in the United States and 1 in Canada). PATIENT(S): Women aged 21-45 years planning controlled ovarian stimulation for in vitro fertilization. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Number of oocytes retrieved, categorized as POR and normal-to-high ovarian response (non-POR). The correlation of AMH level and antral follicle count. RESULT(S): Data were available for 472 participants who completed the study (74 with POR and 398 non-POR). The mean AMH serum level among those with POR was 0.99 ng/mL (median 0.76 ng/mL) compared with 2.83 ng/mL (median 2.36 ng/mL) among the normal-to-high responders. For confirmation of the 0.93 ng/mL AMH level cutoff as a predictor of POR, a receiver operating characteristic analysis gave an area under the curve of 0.852, with corresponding sensitivity and specificity of 63.5% and 89.2%, respectively. The associated positive predictive value was 52.2% and the negative predictive value was 92.9%. The AMH plasma values demonstrated a strong correlation with AMH serum values with an r value = 0.9980. The previously established AMH cutoff of 1.77 ng/mL for antral follicle count >15 resulted in a sensitivity of 83.8% (95% confidence interval [CI] 77.7-88.5) and a specificity of 59.9% (95% CI 54.2-65.4). CONCLUSION(S): This study validated the previously established AMH cut-point for the prediction of POR. Because this cut-point may vary depending on the assay used, the specific AMH assay should be reported in the literature whenever possible.

Multicenter evaluation of the Access AMH antimüllerian hormone assay for the prediction of antral follicle count and poor ovarian response to controlled ovarian stimulation.

OBJECTIVE: To evaluate a new fully automated antimüllerian hormone (AMH) assay for prediction of poor ovarian response (POR) to ovarian stimulation defined as four or fewer oocytes retrieved. DESIGN: Prospective cohort study. SETTING: Thirteen private and academic fertility centers in the United States. PATIENTS(S): A total of 178 women undergoing their first in vitro fertilization (IVF) cycle eligible for the study were consented and enrolled, with data available from 160 women for prediction of POR and 164 women for AMH correlation with antral follicle count (AFC). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Cutoff point for AMH that predicts POR. Correlation of AMH with AFC, and cutoff point for AMH that correlates with antral follicle count >15. RESULT(S): The mean AMH among the poor responders was 0.74 ng/mL, compared with 3.20 ng/mL for normal to high responders. The AMH cutoff at 90% specificity for predicting POR with the use of the receiver operating characteristic (ROC) curve was 0.93 ng/mL, with an associated sensitivity of 74.1%. For prediction of POR, ROC analysis showed that AMH (area under the ROC curve [AUC] = 0.929) was significantly better than FSH (AUC = 0.615; P<.0001). AMH was positively correlated with AFC (Spearman rho = 0.756). The AMH at 90% sensitivity for AFC >15 was 1.75, with specificity of 59.1%. CONCLUSION(S): A fully automated AMH assay can be a useful biomarker for predicting POR in IVF cycles. Because AMH cutoff points vary depending on the assay used, future studies should continue to calibrate test results to clinically important outcomes.

Multi-center clinical evaluation of the Access AMH assay to determine AMH levels in reproductive age women during normal menstrual cycles.

BACKGROUND: AMH is widely used for assessing ovarian reserve, and it is particularly convenient, because it is thought to have minimal variability throughout the menstrual cycle. However, studies assessing the stability of AMH over the menstrual cycle have been conflicting. PURPOSE: The purpose of this study is to determine whether AMH levels vary across the normal menstrual cycle. DESIGN: A multi-center, prospective cohort study conducted at three US centers. METHODS: Fifty females with regular menstrual cycles aged 18-45 underwent serial venipuncture every 3-5 days starting in the early follicular phase and lasting up to 10 collections. AMH was tested using the Access 2 immunoassay system. RESULTS: Age-adjusted mixed-effect models utilizing data from 384 samples from 50 subjects demonstrated a within subject standard deviation of 0.81 (95% CI 0.75-0.88) with a coefficient of variation of 23.8% across the menstrual cycle and between subject standard deviation of 2.56 (95% CI 2.13-3.21) with a coefficient of variation of 75.1%. Intra-class correlation (ICC) of AMH across the menstrual cycle was 0.91. CONCLUSION: Overall, AMH levels, using the automated Access AMH assay, appear to be relatively stable across the menstrual cycle. Fluctuations, if any, appear to be small, and therefore, clinicians may advise patients to have AMH levels drawn at any time in the cycle.

Clinical utility of the Prostate Health Index (phi) for biopsy decision management in a large group urology practice setting.

BACKGROUND: Deciding when to biopsy a man with non-suspicious DRE findings and tPSA in the 4-10 ng/ml range can be challenging, because two-thirds of such biopsies are typically found to be benign. The Prostate Health Index (phi) exhibits significantly improved diagnostic accuracy for prostate cancer detection when compared to tPSA and %fPSA, however only one published study to date has investigated its impact on biopsy decisions in clinical practice. METHODS: An IRB approved observational study was conducted at four large urology group practices using a physician reported two-part questionnaire. Physician recommendations were recorded before and after receiving the phi test result. A historical control group was queried from each site's electronic medical records for eligible men who were seen by the same participating urologists prior to the implementation of the phi test in their practice. 506 men receiving a phi test were prospectively enrolled and 683 men were identified for the historical control group (without phi). Biopsy and pathological findings were also recorded for both groups. RESULTS: Men receiving a phi test showed a significant reduction in biopsy procedures performed when compared to the historical control group (36.4% vs. 60.3%, respectively, P < 0.0001). Based on questionnaire responses, the phi score impacted the physician's patient management plan in 73% of cases, including biopsy deferrals when the phi score was low, and decisions to perform biopsies when the phi score indicated an intermediate or high probability of prostate cancer (phi ≥36). CONCLUSIONS: phi testing significantly impacted the physician's biopsy decision for men with tPSA in the 4-10 ng/ml range and non-suspicious DRE findings. Appropriate utilization of phi resulted in a significant reduction in biopsy procedures performed compared to historical patients seen by the same participating urologists who would have met enrollment eligibility but did not receive a phi test.

Prostate Health Index improves multivariable risk prediction of aggressive prostate cancer.

OBJECTIVE: To examine the use of the Prostate Health Index (PHI) as a continuous variable in multivariable risk assessment for aggressive prostate cancer in a large multicentre US study. MATERIALS AND METHODS: The study population included 728 men, with prostate-specific antigen (PSA) levels of 2-10 ng/mL and a negative digital rectal examination, enrolled in a prospective, multi-site early detection trial. The primary endpoint was aggressive prostate cancer, defined as biopsy Gleason score ≥7. First, we evaluated whether the addition of PHI improves the performance of currently available risk calculators (the Prostate Cancer Prevention Trial [PCPT] and European Randomised Study of Screening for Prostate Cancer [ERSPC] risk calculators). We also designed and internally validated a new PHI-based multivariable predictive model, and created a nomogram. RESULTS: Of 728 men undergoing biopsy, 118 (16.2%) had aggressive prostate cancer. The PHI predicted the risk of aggressive prostate cancer across the spectrum of values. Adding PHI significantly improved the predictive accuracy of the PCPT and ERSPC risk calculators for aggressive disease. A new model was created using age, previous biopsy, prostate volume, PSA and PHI, with an area under the curve of 0.746. The bootstrap-corrected model showed good calibration with observed risk for aggressive prostate cancer and had net benefit on decision-curve analysis. CONCLUSION: Using PHI as part of multivariable risk assessment leads to a significant improvement in the detection of aggressive prostate cancer, potentially reducing harms from unnecessary prostate biopsy and overdiagnosis.

The prostate health index selectively identifies clinically significant prostate cancer.

PURPOSE: The Prostate Health Index (phi) is a new test combining total, free and [-2]proPSA into a single score. It was recently approved by the FDA and is now commercially available in the U.S., Europe and Australia. We investigate whether phi improves specificity for detecting clinically significant prostate cancer and can help reduce prostate cancer over diagnosis. MATERIALS AND METHODS: From a multicenter prospective trial we identified 658 men age 50 years or older with prostate specific antigen 4 to 10 ng/ml and normal digital rectal examination who underwent prostate biopsy. In this population we compared the performance of prostate specific antigen, % free prostate specific antigen, [-2]proPSA and phi to predict biopsy results and, specifically, the presence of clinically significant prostate cancer using multiple criteria. RESULTS: The Prostate Health Index was significantly higher in men with Gleason 7 or greater and "Epstein significant" cancer. On receiver operating characteristic analysis phi had the highest AUC for overall prostate cancer (AUCs phi 0.708, percent free prostate specific antigen 0.648, [-2]proPSA 0.550 and prostate specific antigen 0.516), Gleason 7 or greater (AUCs phi 0.707, percent free prostate specific antigen 0.661, [-2]proPSA 0.558, prostate specific antigen 0.551) and significant prostate cancer (AUCs phi 0.698, percent free prostate specific antigen 0.654, [-2]proPSA 0.550, prostate specific antigen 0.549). At the 90% sensitivity cut point for phi (a score less than 28.6) 30.1% of patients could have been spared an unnecessary biopsy for benign disease or insignificant prostate cancer compared to 21.7% using percent free prostate specific antigen. CONCLUSIONS: The new phi test outperforms its individual components of total, free and [-2]proPSA for the identification of clinically significant prostate cancer. Phi may be useful as part of a multivariable approach to reduce prostate biopsies and over diagnosis.

Prospective multicenter evaluation of the Beckman Coulter Prostate Health Index using WHO calibration.

PURPOSE: Reported prostate specific antigen values may differ substantially among assays using Hybritech® or WHO standardization. The Beckman Coulter® Prostate Health Index and [-2]proPSA are newly approved serum markers associated with prostate cancer risk and aggressiveness. We studied the influence of assay standardization on these markers. MATERIALS AND METHODS: Prostate specific antigen, percent free prostate specific antigen and [-2]proPSA were measured using Hybritech calibration in 892 men from a prospective, multicenter study undergoing prostate biopsy. We calculated the Prostate Health Index using the equation, ([-2]proPSA/free prostate specific antigen) × PSA. Index performance characteristics for prostate cancer detection were then determined using recalculated WHO calibration prostate specific antigen values. RESULTS: The median Prostate Health Index was significantly higher in men with prostate cancer than in those with negative biopsies using WHO values (47.4 vs 39.8, p <0.001). The index offered improved discrimination of prostate cancer detection on biopsy (AUC 0.704) compared to percent free or total prostate specific antigen using the WHO calibration. CONCLUSIONS: The Prostate Health Index can be calculated using Hybritech or WHO standardized assays. It significantly improved prediction of the biopsy outcome over that of percent free or prostate specific antigen alone.

Multi-center analytical performance evaluation of the Access Hybritech® p2PSA immunoassay.

BACKGROUND: Total PSA assays measure both complexed and non-complexed forms of PSA while free PSA assays only measure non-complexed forms. Free PSA is a mixture of isoforms including immature PSA (proPSA) with retained portions of the leader sequence (e.g. [-7], [-4], and [-2]proPSA) and nicked forms (BPSA). ProPSA isoforms in male sera have been associated with prostate cancer. This study characterized the analytical performance of a chemiluminescent immunoassay for [-2]proPSA. METHODS: The Access Hybritech p2PSA assay is a sandwich immunoassay using an anti-[-2]proPSA monoclonal antibody attached to paramagnetic beads and an anti-PSA monoclonal antibody conjugated to alkaline phosphatase calibrated with recombinant [-2]proPSA. Analytical studies including sensitivity (CLSI EP17-A) and imprecision (CLSI EP5-A2) were performed. RESULTS: The Access Hybritech p2PSA assay for [-2]proPSA had a dynamic range of 0.5 to 5000 pg/ml. The total CV of the assay was <7% for [-2]proPSA concentrations between 20 and 1000 pg/ml. The LOB was 0.50 pg/ml, LOD 0.69 pg/ml, and LOQ 3.23 pg/ml (20% CV). There was no hook effect up to 15,000 pg/ml. There was a <5% difference between calibrator and reagent lots and no interference from normal serum constituents. CONCLUSIONS: The Access Hybritech p2PSA assay is a robust immunoassay for the measurement of serum [-2]proPSA.

A multicenter study of [-2]pro-prostate specific antigen combined with prostate specific antigen and free prostate specific antigen for prostate cancer detection in the 2.0 to 10.0 ng/ml prostate specific antigen range.

PURPOSE: Prostate specific antigen and free prostate specific antigen have limited specificity to detect clinically significant, curable prostate cancer, leading to unnecessary biopsy, and detection and treatment of some indolent tumors. Specificity to detect clinically significant prostate cancer may be improved by [-2]pro-prostate specific antigen. We evaluated [-2]pro-prostate specific antigen, free prostate specific antigen and prostate specific antigen using the formula, ([-2]pro-prostate specific antigen/free prostate specific antigen × prostate specific antigen(1/2)) to enhance specificity to detect overall and high grade prostate cancer. MATERIALS AND METHODS: We enrolled 892 men with no history of prostate cancer, normal rectal examination, prostate specific antigen 2 to 10 ng/ml and 6-core or greater prostate biopsy in a prospective multi-institutional trial. We examined the relationship of serum prostate specific antigen, free-to-total prostate specific antigen and the prostate health index with biopsy results. Primary end points were specificity and AUC using the prostate health index to detect overall and Gleason 7 or greater prostate cancer on biopsy compared with those of free-to-total prostate specific antigen. RESULTS: In the 2 to 10 ng/ml prostate specific antigen range at 80% to 95% sensitivity the specificity and AUC (0.703) of the prostate health index exceeded those of prostate specific antigen and free-to-total prostate specific antigen. An increasing prostate health index was associated with a 4.7-fold increased risk of prostate cancer and a 1.61-fold increased risk of Gleason score greater than or equal to 4 + 3 = 7 disease on biopsy. The AUC of the index exceeded that of free-to-total prostate specific antigen (0.724 vs 0.670) to discriminate prostate cancer with Gleason 4 or greater + 3 from lower grade disease or negative biopsy. Prostate health index results were not associated with age and prostate volume. CONCLUSIONS: The prostate health index may be useful in prostate cancer screening to decrease unnecessary biopsy in men 50 years old or older with prostate specific antigen 2 to 10 ng/ml and negative digital rectal examination with minimal loss in sensitivity.

A prospective, multicenter, National Cancer Institute Early Detection Research Network study of [-2]proPSA: improving prostate cancer detection and correlating with cancer aggressiveness.

BACKGROUND: The free prostate-specific antigen (PSA) isoform, [-2]proPSA, has been shown to be associated with prostate cancer. The study objective was to characterize the clinical utility of serum [-2]proPSA for prostate cancer detection and assess its association with aggressive disease. METHODS: From among 669 subjects in a prospective prostate cancer detection study at four National Cancer Institute Early Detection Research Network clinical validation centers, 566 were eligible. Serum PSA, free PSA, and [-2]proPSA were measured (Beckman Coulter Access 2 Analyzer). RESULTS: Two hundred and forty-five (43%) of the 566 participants had prostate cancer on biopsy. At 70% specificity, the sensitivity of %[-2]proPSA ([-2]proPSA/fPSA) was 54% [95% confidence interval (CI), 48-61%; null hypothesis, 40%]. Including %[-2]proPSA in a multivariate prediction model incorporating PSA and %fPSA improved the performance (P<0.01). In the 2 to 4 ng/mL PSA range, %[-2]proPSA outperformed %fPSA (receiver operator characteristic-areas under the curve, 0.73 versus 0.61; P=0.01). At 80% sensitivity, %[-2]proPSA had significantly higher specificity (51.6%; 95% CI, 41.2-61.8%) than PSA (29.9%; 95% CI, 21.0-40.0%) and %fPSA (28.9%; 95% CI, 20.1-39.0%). In the 2 to 10 ng/mL PSA range, a multivariate model had significant improvement (area under the curve, 0.76) over individual PSA forms (P<0.01 to <0.0001). At 80% sensitivity, the specificity of %[-2]proPSA (44.9%; 95% CI, 38.4-51.5%) was significantly higher than PSA (30.8%; 95% CI, 24.9-37.1%) and relatively higher than %fPSA (34.6%; 95% CI, 28.5-41.4%). %[-2]proPSA increased with increasing Gleason score (P<0.001) and was higher in aggressive cancers (P=0.03). CONCLUSIONS: In this prospective study, %[-2]proPSA showed potential clinical utility for improving prostate cancer detection and was related to the risk of aggressive disease. IMPACT: The addition of %[-2]proPSA could affect the early detection of prostate cancer.