Ratio of free or complexed prostate-specific antigen (PSA) to total PSA: which ratio improves differentiation between benign prostatic hyperplasia and prostate cancer?

BACKGROUND: The aim of this study was to compare the diagnostic utility of a new assay that measures all forms of prostate-specific antigen complexed (cPSA) to serum proteins except alpha(2)-macroglobulin with the assay of free PSA (fPSA) and the corresponding ratios to total PSA (tPSA) to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa). METHODS: Serum samples were collected from 91 men without prostate disease and with normal digital rectal examination (controls), 144 untreated patients with PCa, and 89 patients with BPH. tPSA and cPSA were measured using the Bayer Immuno 1 system; fPSA and the additional tPSA were measured with the Roche Elecsys system. RESULTS: The median cPSA/tPSA, fPSA/tPSA, and fPSA/cPSA ratios were significantly different between patients with BPH and PCa (78.7% vs 90.7%, 25.5% vs 12.1%, and 36.8% vs 14.3%, respectively; P <0.001). No correlations of cPSA and its ratios to tumor stage and grade were found. ROC analysis showed that cPSA was not different from tPSA (areas under the curve, 0.632 vs 0.568), whereas the cPSA/tPSA ratio was similar to the fPSA/tPSA ratio in increasing discrimination between BPH and PCa patients with tPSA concentrations in the tPSA gray zone between 2 and 10 microg/L (areas under the curve, 0.851 vs 0.838). CONCLUSIONS: Compared with tPSA, the fPSA/tPSA and cPSA/tPSA ratios both improve the differentiation between BPH and PCa comparably and are similarly effective in reducing the rate of unnecessary biopsies, whereas cPSA alone does not have any effect.     

血清特异性抗原在前列腺良恶性肿瘤诊断中的应用

目的比较血清总前列腺特异性抗原（tPSA）、游离前列腺特异性抗原（fPSA）与tPSA的比值（f／t）、复合前列腺特异性抗原（cPSA）鉴别诊断前列腺增生（BPH）和前列腺癌（PCa）的价值。方法150例分为3组：健康对照组50例，前列腺增生组50例，前列腺癌50例，患者血清tPSA、fPSA浓度，计算f／t比值，cPsA／tPsA、fP—SA／cPSA比值。结果PCa组的cPSA／tPSA、fPSA／tPSA和fPSA／cPSA比值的均值与BPH组差异有统计学意义（P〈0．001），fPSA／cPSA与fPSA／tPSA比值密切相关（r=0．8810）。结论血清tPSA为前列腺的标志物，而f／t及fPsA／cPsA作为tPSA的辅助指标，在鉴别良恶性肿瘤中有重要意义。     

The measurement of complexed prostate-specific antigen has a better performance than total prostate-specific antigen.

The aim of this study was to compare the diagnostic utility of complexed prostate-specific antigen (cPSA) with total PSA (tPSA) in screening for prostate cancer. Serum concentrations of tPSA and cPSA were measured in 4479 adult men during the prostate cancer screening program in the Saarland region (Germany). The percentage of men with c/tPSA ratio above the cut-off value of 0.75 increased with increasing tPSA intervals: tPSA 0-0.9 microg/l, 4.4%; 1.0-1.9 microg/l, 24.3%; 2.0-2.9 microg/l, 43.9%; 3.0-3.9 microg/l, 50.4%; and 4.0-20 microg/l, 60.2%. The commonly accepted tPSA cut-off value of 3.9 microg/l matched to the 93rd percentile of the overall population (corresponding cPSA value, 2.9 microg/l). A total of 202 men out of 313 with increased cPSA had increased c/tPSA ratio (cut-off > or = 0.75) vs. 186 out of 312 men with increased tPSA. Thus, an additional 16 men at high risk for prostate cancer were selected only if cPSA was utilised as a first line parameter. Our data show that, compared to tPSA, cPSA measurement will always detect more high-risk patients, independent of the cut-off levels utilised for cPSA, tPSA and c/tPSA ratio. cPSA is more effective than tPSA in selecting subjects with an elevated c/tPSA ratio who are at high risk of prostate cancer. Thus, cPSA might be seen as the superior first-line parameter in screening for prostate cancer. Using lower cut-off values for tPSA or cPSA than the commonly accepted values seems reasonable for screening purposes.     

Centaur CP检测前列腺特异性抗原的临床应用研究

目的探讨总前列腺特异性抗原(tPSA)、复合前列腺特异性抗原(cPSA)及cPSA/tPSA比值在前列腺癌(PCa)诊断中的应用价值。方法选取中国人民解放军第一医院确诊的PCa患者73例、前列腺良性增生(BPH)患者76例及健康对照70例。采用西门子化学发光Advia Centaur CP检测各组tPSA、cPSA及c/t比值。结果 PCa组的tPSA、cPSA及c/t比值显著高于BPH组,差异有统计学意义(P0.05);ROC曲线显示tPSA截断值为19.89μg/L,cPSA截断值为13.14μg/L时,区分PCa和BPH的灵敏度分别可达94.5%、95.9%,特异度分别为97.9%、91.8%,曲线下最大面积为0.96、0.98,尤登指数为0.924、0.877;χ2检验显示tPSA、cPSA与病理诊断结果无相关性(χ2分别为102.036、151.409,P0.05)。结论 tPSA、cPSA的水平分别达到19.89μg/L和13.14μg/L时应高度怀疑患者为PCa或PCa治疗后复发,应及时进行治疗。     

Interchangeability of measurements of total and free prostate-specific antigen in serum with 5 frequently used assay combinations: an update

BACKGROUND: The comparability of total and free prostate-specific antigen (tPSA and fPSA) results among commercial PSA assays has been suggested to be improved by calibration to WHO PSA reference materials and the development of equimolar-response assays. To characterize the current situation, we assessed 5 frequently used commercial assay combinations for tPSA and fPSA regarding the interchangeability of the PSA values and the ratio of fPSA to tPSA (%fPSA), equimolar characteristics, and diagnostic accuracy. METHODS: Sera from 314 patients with prostate cancer (PCa) and 282 men with no evidence of prostate cancer (NPCa) were measured with tPSA and fPSA assays from Abbott (AxSYM), Beckman Coulter (Access), Diagnostic Products Corporation (Immulite 2000), and Roche (Elecsys 2010) and with tPSA and complexed PSA (cPSA) assays from Bayer (ADVIA Centaur). RESULTS: Method comparisons (Passing and Bablok regressions; Bland-Altman plots) showed assay-dependent results for tPSA, fPSA, and %fPSA. With the Access tPSA values taken as 100%, tPSA concentrations varied from 87% (AxSYM and ADVIA Centaur) to 115% (Immulite), leading to different numbers of patients classified according to the commonly recommended tPSA cutoffs for performing a biopsy. Different %fPSA values also led to assay-dependent ROC analysis results, a finding that shows the importance for the diagnostic accuracy. CONCLUSION: Interchangeability of tPSA, fPSA, and %fPSA values obtained by commercial PSA assays remains inadequate, but attention to this issue may minimize the misinterpretation of PSA results obtained by different assays.     

复合前列腺特异性抗原在前列腺癌诊断中的应用

目的探讨复合前列腺特异性抗原（cPSA）及cPSA/tPSA比值在前列腺癌（PCa）诊断中的应用价值。方法分析PCa患者22例、前列腺增生（BPH）患者48例及前列腺正常对照组50例患者的tPSA、cPSA及cPSA/tPSA比值,并进行统计学分析。结果 PCa组的tPSA和cPSA浓度明显高于BPH组,差异具有统计学意义（P〈0.05）;cPSA/tPSA比值在对照组与PCa组及BPH组与PCa组之间的差异均具有统计学意义（P〈0.01）。结论 cPSA与tPSA均可筛选及早期发现PCa,结合cPSA/tPSA比值可以更有效地提高对PCa诊断的准确率。     

Elevated prostate specific antigen and reduced 10-year survival among a cohort of Danish men consecutively referred from primary care to an urological department during 2005–2006

It remains unclear whether total prostate specific antigen (tPSA) or complex PSA (cPSA) has the best diagnostic performance. Additionally, the utility of percentage free PSA (%fPSA) is still debated. Our objectives were to compare the diagnostic performances of tPSA, cPSA, and %fPSA among patients referred from GP to an Urological Specialist and to investigate prognostic factors and survival in the cohort. A total of 1261 consecutive male patients without previously known prostate cancer (PCa) were referred to the same Department of Urology during June 2005 to August 2006. Some 299 patients were diagnosed with PCa and 962 patients were found without PCa. Among the PCa patients, the median age, tPSA, cPSA, and %fPSA levels were 70.8 years, 13.4?μg/L, 10.8?μg/L, and 12.6%. For patients without PCa the results were 67.5 years, 2.5?μg/L, 1.9?μg/L, and 24.9%. The sensitivity, specificity, PVpos, PVneg, and efficiency of tPSA and cPSA were overlapping (p?>?.05). In the tPSA interval >4?μg/L –?≤20?μg/L, %fPSA excluded PCa with a PVneg of 72.4%; 38.5% of PCa patients had a tPSA concentration >20?μg/L at the time of referral and these patients had a reduced 10-year survival as compared to patients with tPSA concentrations ≤20?μg/L. In conclusion, tPSA and cPSA showed similar diagnostic performances. %fPSA provided additional diagnostic information at tPSA concentrations >4?μg –?≤20?μg/L. The high percentage of patients with tPSA concentrations >20?μg/L indicate delayed use of tPSA resulting in advanced disease at presentation and reduced patient survival.     

Intraindividual variation of PSA,free PSA and complexed PSA in a cohort of patients with prostate cancer managed with watchful observation

OBJECTIVE: To determine the intraindividual variation of prostate-specific antigen (PSA) isoforms in prostate cancer patients managed conservatively with watchful observation. METHODS: Patients with favorable clinical parameters (stage T1b-T2b N0 M0, Gleason score 相似文献   

Improved diagnostic classification of alcohol abusers by combining carbohydrate-deficient transferrin and gamma-glutamyltransferase

BACKGROUND: Biochemical markers can provide objective evidence of high alcohol consumption. However, currently available markers have limitations in their diagnostic performance. METHODS: The diagnostic values of the most frequently used markers [carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), aspartate aminotransferase, alanine aminotransferase, and mean corpuscular volume] were studied in an analysis of six different clinical studies (n = 1412) on alcohol abusers and social drinkers. The purpose of the analyses was to determine whether a combination of markers would improve the diagnosis of subjects. RESULTS: Discrimination between alcohol abusers and social drinkers, as measured by the areas under nonparametric ROC plots, was significantly better (P<0.001) for the new combined marker [gamma-CDT = 0.8. ln(GGT) + 1.3. ln(CDT)] than for any of the separate markers or combination of CDT or GGT with other markers. The cutoff values for gamma-CDT (6.5) can be taken to be the same among males and females. CONCLUSIONS: The combined variable gamma-CDT is a powerful tool to discriminate alcohol abusers from social drinkers and is recommended for clinical use.     

游离PSA和复合PSA在前列腺癌诊断中的应用

目的评估三种形式的前列腺特异性抗原:总前列腺特异性抗原(tPSA)、游离前列腺特异性抗原(fPSA)、复合前列腺特异性抗原(cPSA)及其比值在前列腺癌诊断中的应用。方法150名研究对象分为三组:正常对照组50人,前列腺增生(BPH)组50人,前列腺癌(PCa)组50人。用全自动化学发光免疫法分别测定他们的tPSA、fPSA和cPSA,并计算其比值。结果Pca组的cPSA／tPSA、fPSA／tPSA和fPSA／cPSA比值的均值与BPH组有显著差异(分别为91.0％／68.0％,12.1％／26.3％和13.3％／38.8％,P<0.001),fPSA／cPSA与fPSA／tPSA比值密切相关(r=0.8820)。结论与tPSA相比,cPSA／tPSA、fPSA／tPSA和fPSA／cPSA都可增强其对BPH和PCa的鉴别诊断作用。     

Long-distance mountain biking does not disturb the measurement of total, free or complexed prostate-specific antigen in healthy men.

PURPOSE: Mechanical manipulation of the prostate is a generally accepted interfering factor for the measurement of prostate-specific antigen (PSA). However, only few studies have focused on common daily mechanical manipulations, such as bicycle riding. Furthermore, physical exercise is also supposed to modulate PSA serum concentration. Long-distance mountain biking is an excellent model to study the combined effect of mechanical prostate manipulation by bicycle riding and strenuous endurance exercise on total, free and complexed PSA (tPSA, fPSA, cPSA). MATERIALS AND METHODS: We investigated tPSA, fPSA and cPSA in 42 healthy male cyclists (mean age 35+/-6 years) before and after a 120 km off-road mountain bike race. Blood sampling was done before, 15 min and 3 h after the race. RESULTS: Mean race time was 342+/-65 min. All athletes had normal serum levels of tPSA, fPSA or cPSA. None of these parameters was modified by the race. CONCLUSIONS: In healthy men the measurement of tPSA, fPSA and cPSA is not disturbed by preceding long distance mountain biking or endurance exercise. Based on the present data, there is no evidence for a recommendation to limit bicycle riding or physical activity before the measurement of tPSA, fPSA or cPSA.     

Diagnostic accuracy of serum asialo-alpha1-acid glycoprotein concentration for the differential diagnosis of liver cirrhosis and hepatocellular carcinoma

BACKGROUND: Serum asialoglycoproteins concentration are increased in patients with hepatic disease. We developed an antibody-lectin sandwich assay that is sensitive and specific to measure asialo-alpha(1)-acid glycoprotein (AsAGP) concentration in human serum and evaluated it as a biochemical marker for hepatic disease. METHODS: Serum AsAGP concentration was measured by antibody-lectin sandwich assay with 610 serum specimens of patients with hepatic disease. Serum from 41 healthy donors and 155 patients with non-hepatic disease served as negative controls. The AsAGP values were analyzed by receiver operator characteristics (ROC) curve analysis. The diagnostic accuracy of AsAGP value was compared with those of the conventional biochemical markers in the liver function test. RESULTS: Serum AsAGP concentration in 83% of patients with liver cirrhosis (LC) and 89% of patients with hepatocellular carcinoma (HCC) was increased over the cutoff value (1.33 microg/ml), indicating that an increase of serum AsAGP concentration is restricted to LC or HCC cases. The area under curve (AUC) in the ROC curve was 0.919 for LC and 0.946 for HCC. CONCLUSIONS: Serum AsAGP concentration exhibited good diagnostic accuracy as a biochemical marker for LC and HCC. The addition of AsAGP to conventional liver function tests may significantly improve the diagnosis and prognosis.     

Reproducibility and accuracy of measurements of free and total prostate-specific antigen in serum vs plasma after long-term storage at -20 degrees C

BACKGROUND: Long-term frozen storage may alter the results of prostate-specific antigen (PSA) measurements, mainly because of degradation of free PSA (fPSA) in vitro. We compared the effects of long-term storage on fPSA, total PSA (tPSA), and complexed PSA (cPSA) in serum vs EDTA-plasma samples. METHODS: We measured fPSA and tPSA concentrations in matched pairs of archival serum and EDTA-plasma samples (stored frozen at -20 degrees C for 20 years) from a large population-based cohort in Malm?, Sweden. We also compared concentrations in age-matched men with those in samples not subjected to long-term storage, obtained from participants in a population-based study of prostate cancer screening in G?teborg, Sweden. These contemporary samples were handled according to standardized preanalytical and analytical protocols aimed at minimizing in vitro degradation. tPSA and fPSA measurements were performed with a commercial assay (Prostatus Dual Assay; Perkin-Elmer Life Sciences). RESULTS: Concentrations of tPSA and fPSA and calculated cPSA (tPSA - fPSA) in archival plasma were not significantly different from those in contemporary serum from age-matched men. In archival serum, however, random variability of fPSA was higher vs plasma than in contemporary samples, whereas systematic error of fPSA analyses was similarly small in archival and contemporary serum and plasma. CONCLUSIONS: Concentrations of tPSA and calculated cPSA were highly stable in plasma and serum samples subjected to long-term storage at -20 degrees C. Greater random variability, rather than a systematic decrease, may explain differences in fPSA analyses observed in archival serum.     

Multicenter evaluation of an artificial neural network to increase the prostate cancer detection rate and reduce unnecessary biopsies

BACKGROUND: The percentage of free prostate-specific antigen (%fPSA) has been shown to improve specificity for the diagnosis of prostate cancer (PCa) over total PSA (tPSA). A multicenter study was performed to evaluate the diagnostic value of a %fPSA-based artificial neural network (ANN) in men with tPSA concentrations between 2 and 20 microg/L for detecting patients with increased risk of a positive prostate biopsy for cancer. METHODS: We enrolled 1188 men from six different hospitals with PCa or benign prostates between 1996 and 2001. We used a newly developed ANN with input data of tPSA, %fPSA, patient age, prostate volume, and digital rectal examination (DRE) status to calculate the risk for the presence of PCa within different tPSA ranges (2-4, 4.1-10, 2-10, 10.1-20, and 2-20 microg/L) at the 90% and 95% specificity or sensitivity cutoffs, depending on the tPSA concentration. ROC analysis and cutoff calculations were used to estimate the diagnostic improvement of the ANN compared with %fPSA alone. RESULTS: In the low tPSA range (2-4 microg/L), the ANN detected 72% and 65% of cancers at specificities of 90% or 95%, respectively. At 4-10 microg/L tPSA, the ANN detected 90% and 95% of cancers with specificities of 62% and 41%, respectively. Use of the ANN with 2-10 microg/L tPSA enhanced the specificity of %fPSA by 20-22%, thus reducing the number of unnecessary biopsies. CONCLUSIONS: Enhanced accuracy of PCa detection over that obtained using %fPSA alone can be achieved with a %fPSA-based ANN that also includes clinical information from DRE and prostate volume measurements.     

血清前列腺特异性抗原对前列腺良恶性肿瘤诊断的临床应用

目的研究血清前列腺特异性抗原(tPSA)、复合前列腺特异性抗原(cPSA)及cPSA/tPSA比值(C/T)在前列腺增生(BPH)和前列腺癌(PCa)鉴别诊断中的应用。方法收集2009年5月至2015年12月该院门诊和住院患者血清共184例,其中BPH组患者80例,PCa组患者36例,其他疾病组患者68例。化学发光法检测tPSA、cPSA浓度,计算C/T值,比较3组的tPSA、cPSA浓度和C/T值。结果 PCa组血清tPSA、cPSA浓度及C/T值均高于其他疾病组和BPH组,且差异具有统计学意义(P0.01);而BPH组和其他疾病组的C/T值差异无统计学意义(P0.05);PCa组的tPSA和cPSA浓度相关性好,回归方程为cPSA=0.708×tPSA+0.219,且相关系数(r=0.956)高于BPH组的tPSA和cPSA浓度相关系数(r=0.651);血清tPSA浓度在4.0~10.0ng/mL灰区内各组间血清tPSA、cPSA浓度和C/T值差异无统计学意义(P0.05)。结论联合检测血清tPSA、cPSA浓度并计算C/T值,在鉴别诊断前列腺良恶性肿瘤中具有重要意义。     

利用ROC曲线评价前列腺癌诊断指标的诊断价值

目的：探讨血清总前列腺特异性抗原（total prostate specific antigen, tPSA）、游离PSA（free PSA, fPSA）及其比值（fPSA/tPSA）在诊断前列腺癌（prostatic carcinoma, PCA）中的价值。方法收集2008年1月至2012年12月于我院就诊的23例PCA患者,246例良性前列腺增生（benign prostate hy-perplasia, BPH）患者,及85例同期健康体检者,用化学发光法检测受试者血清中的tPSA、fPSA及其比值fPSA/tPSA,通过受试者工作特征（receiver operating characteristic, ROC）曲线分析各指标用于诊断PCA的诊断效能。结果 tPSA、fPSA检测结果三组间比较,差异均有统计学意义（P均＜0．01）,而fPSA/tPSA三组间比较,差异无统计学意义（P＞0．05）。PCA组tPSA和fPSA检测水平均明显高于BPH组和健康对照组,差异均有统计学意义（P均＜0．05）。 BPH组tPSA和fPSA检测水平均高于健康对照组,差异均有统计学意义（P均＜0．05）。经ROC曲线分析,tPSA、fPSA、tPSA＋fPSA以及fPSA/tPSA用于诊断PCA的ROC 曲线下面积分别为：0．995、0．991、0．995、0．362。 tPSA、fPSA 诊断 PCA 的 cutoff 值分别为23．09μg/L、4．05μg/L,对应的灵敏度和特异性分别为100．0％、96．1％和100．0％、94．3％。结论 tPSA、fPSA对于诊断PCA有较好的诊断效能,其cutoff值分别为23．09μg/L、4．05μg/L。     

血清前列腺健康指数对 tPSA灰区前列腺癌患者的诊断价值探讨

目的　探讨前列腺健康指数（PHI）在血清总前列腺特应性抗原（tPSA）灰区（4~10 ng/ml）前列腺癌（PCa）患者中的诊断价值。方法　选择 2018年 3月～ 2019年 10月上海市金山区亭林医院泌尿外科收治的 94例血清 tPSA在 4～ 10 ng/ml的老年男性患者临床资料。其中 PCa组 21例,前列腺良性增生（ BPH）73例。检测两组患者血清中 tPSA、游离 PSA（fPSA）以及前列腺特异性抗原前体 2型（p2PSA）的指标水平,从而计算得出 fPSA/tPSA比值和 PHI,并绘制 tPSA, fPSA/tPSA, p2PSA以及 PHI的受试者工作特征（ ROC）曲线,得出曲线下面积（ AUC）、95%CI以及截断值（ cut off value）,分析 tPSA, fPSA/tPSA, p2PSA以及 PHI的检测对 PCa患者的早期诊断价值。结果　两组患者的血清 tPSA,fPSA和p2PSA水平差异均无统计学意义（U=899,450和 261.5,均 P >0.05）;两组患者 fPSA/tPSA（U=261.5, P =0.023）与 PHI（t=1275.5,P<0.001）指标的差异有统计学意义（均 P <0.05）。tPSA, fPSA/tPSA, p2PSA以及 PHI的 ROC曲线下面积分别为 0.586,0.676,0.613和 0.832,其中 tPSA, fPSA/tPSA和 p2PSA（AUC值均 <0.7）的诊断效能较低,而 PHI的诊断效能较高。血清 PHI的准确度（ 81.9%）明显高于 tPSA, fPSA/tPSA和 p2PSA,差异有统计学意义（ χ2=6.975, 4.145和 6.211, 均 P <0.05）。tPSA及 p2PSA指标对提高 PCa的诊断效率无明显助益（均 P >0.05）,fPSA/tPSA和 PHI明显提高 Pca的诊断效力（ P<0.05）,其中 PHI的诊断效果最佳（ P<0.001）,PHI的 AUC值 0.832（95% CI: 0.733～ 0.931）高于 fPSA/tPSA的 AUC值 0.676（95% CI: 0.539～ 0.812）,差异有统计学意义（Z=2.758,P<0.01）。结论　PHI诊断 tPSA灰区 PCa患者的诊断效能与准确性均较高,具有比 tPSA, fPSA/tPSA和 p2PSA更高的诊断价值。     

Combining markers of nephrotoxicity and hepatotoxicity for improved monitoring and detection of chronic alcohol abuse.

BACKGROUND: Most of the commonly used markers of chronic alcohol abuse reflect alcohol hepatotoxicity; however, such abuse is deleterious to the kidneys as well. Combined use of serum markers of liver origin and urinary markers of kidney origin may be of diagnostic advantage. METHODS: The study was performed in 73 male alcoholics undergoing detoxification and 36 male alcoholics who had maintained abstinence for > or =6 weeks. Factor analysis, discriminant analysis and receiver operating characteristic (ROC) analysis were used to assess the discriminative power of two urinary markers of alcohol nephrotoxicity, namely beta-N-acetylhexosaminidase (Hex, EC 3.2.1.52) and alanine aminopeptidase (EC 3.4.11.2), and of three serum markers of alcohol hepatotoxicity, namely aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2) and gamma-glutamyltransferase (GGT, EC 2.3.2.2), and of their quantitative combinations. RESULTS: The discriminative power of the urinary markers matched that of the serum markers. Hex and GGT appeared to be the best for discriminating the study groups. Their combination given by the equation G&H=0.62 x ln(GGT)+0.72 x ln(Hex) showed excellent discriminative ability (ROC area under the curve 0.92) that was significantly higher than that of any single marker in this report, indicating superior diagnostic accuracy of the compound marker. CONCLUSIONS: Kidney-derived urinary markers, particularly Hex, can complement or replace, if necessary, serum markers of chronic alcohol abuse that relate to alcohol hepatotoxicity. The compound marker proposed seems a promising tool for the monitoring and perhaps detection of chronic alcohol abuse and warrants further studies.     

Evaluation of the clinical performance of equimolar- and skewed-response total prostate-specific antigen assays versus complexed and free PSA assays and their ratios in discriminating between benign prostatic hyperplasia and prostate cancer

BACKGROUND: Prostate-specific antigen (PSA) exists in human serum in two principal forms, free PSA (fPSA) and protein-complexed PSA, predominantly PSA-ACT (alpha(1)-antichymotrypsin). Equimolar response (EMR) total PSA (tPSA) immunoassays measure each of these forms equally while skewed-response (SKR) assays overestimate or underestimate the tPSA concentration. The advantages of EMR over SKR tPSA assays are controversial. METHODS: We used five nonhuman serum-based samples each containing a different proportion of fSPA:PSA-ACT (0:100 to 100:0, %:%) and patients' serum samples from men with histologically confirmed benign prostatic hyperplasia (BPH) (n=94) or PCA (n=30) and a wide range of fPSA concentrations to investigate the molar response status of six tPSA assays. Receiver-operator characteristic (ROC) curve analysis was used to compare the discriminatory power of these assays in distinguishing men with BPH from those with PCA. RESULTS: The Bayer Immuno-1 tPSA (BtPSA) assay demonstrated EMR characteristics and diagnostic accuracy similar to the Hybritech Tandem-E and Tandem-R tPSA assays. At 90% sensitivity, EMR tPSA assays had higher specificity than SKR tPSA assays. CONCLUSIONS: The BtPSA assay is an EMR tPSA assay and EMR assays provide improved diagnostic specificity over SKR tPSA assays.     

Diagnostic Accuracy of a New Instrument for Detecting Cognitive Dysfunction in an Emergent Psychiatric Population: The Brief Cognitive Screen

Objectives: In certain clinical contexts, the sensitivity of the Mini‐Mental State Examination (MMSE) is limited. The authors developed a new cognitive screening instrument, the Brief Cognitive Screen (BCS), with the aim of improving diagnostic accuracy for cognitive dysfunction in the psychiatric emergency department (ED) in a quick and convenient format. Methods: The BCS, consisting of the Oral Trail Making Test (OTMT), animal fluency, the Clock Drawing Test (CDT), and the MMSE, was administered to 32 patients presenting with emergent psychiatric conditions. Comprehensive neuropsychological evaluation served as the criterion standard for determining cognitive dysfunction. Diagnostic accuracy of the MMSE was determined using the traditional clinical cutoff and receiver operating characteristic (ROC) curve analyses. Diagnostic accuracy of individual BCS components and BCS Summary Scores was determined by ROC analyses. Results: At the traditional clinical cutoff, MMSE sensitivity (46.4%) and total diagnostic accuracy (53.1%) were inadequate. Under ROC analyses, the diagnostic accuracy of the full BCS Summary Score (area under the curve [AUC] = 0.857) was comparable to the MMSE (AUC = 0.828). However, a reduced BCS Summary Score consisting of OTMT Part B (OTMT–B), animal fluency, and the CDT yielded classification accuracy (AUC = 0.946) that was superior to the MMSE. Conclusions: Preliminary findings suggest the BCS is an effective, convenient alternative cognitive screening instrument for use in emergent psychiatric populations. ACADEMIC EMERGENCY MEDICINE 2010; 17:307–315 © 2010 by the Society for Academic Emergency Medicine