Differential diagnosis of pleural effusions

Pleural effusion is an important and common clinical finding. Pleural effusions can be readily obtained for analysis, and the examination of the cells therein is considered to be one of the most important diagnostic tools available for differentiating between malignant and non-malignant effusions. The present study was undertaken to test the diagnostic value of the determination of CEA in pleural fluid for a variety of diseases. Sixteen patients with pleural effusions were studied. Seven patients had carcinoma of the cervix, 7 of the ovary and 2 of the corpus. The positive rate of malignant cells was 81%. Among malignant effusions, only 44% of patients showed a CEA value above 10 mg/ml. This investigation suggests that cytological examination of pleural fluid is of considerable clinical significance for diagnosing the nature of pleural effusions, and effusion fluid CEA assay may provide a useful adjunct in the evaluation of effusion fluids for malignancy.     

Evaluation of pleural fluid human epididymis 4 (HE4) as a marker of malignant pleural effusion

Pleural effusion is a commonly encountered problem in clinical practice, and pleural fluid analysis is usually the first step towards identifying the underlying etiology. Numerous studies have been published analyzing the potential utility of measuring biomarkers in pleural fluid as possible indicators of a malignant effusion; however, there are no studies that have examined the presence of human epididymis 4 (HE4) in pleural effusions. The aims of this study were to assess pleural effusion and serum concentrations of HE4 in patients with different types of pleural effusions and to evaluate the diagnostic performance of HE4 in detecting malignant pleural effusion. A prospective cohort study was carried out of 88 consecutive patients presenting with pleural effusions. The patients were divided into three groups: 22 patients with transudative effusions, 32 patients with non-malignant exudative effusions, and 34 patients with malignant pleural effusions. Blood and pleural fluid HE4 levels were measured using immunoassay. Both serum HE4 levels and pleural effusion HE4 levels were significantly higher in patients with malignant effusions than in patients with transudative or non-malignant exudative effusions. A pleural fluid HE4 cutoff value of 1,675?pmol/L was found to predict malignant pleural effusions with a diagnostic sensitivity of 85.3?% and specificity of 90.7?%. The current study reports a novel finding of increased serum and pleural fluid HE4 levels in patients with malignant effusions compared to non-malignant effusions. This finding has the potential to strengthen the diagnostic performance of tumor markers in detecting malignant pleural effusions.     

Potential diagnostic value of methylation profile in pleural fluid and serum from cancer patients with pleural effusion

BACKGROUND: The objective of this study was to investigate the diagnostic value of methylation profiles for discrimination between malignant and benign pleural effusions. A secondary objective was to examine the concordance of methylation in samples of serum and pleural fluid. METHODS: The authors used methylation-specific polymerase chain reaction (MSP) analysis to examine the promoter methylation status of 4 genes in patients with pleural effusion: death-associated protein kinase (DAPK), Ras association domain family 1A (RASSF1A), retinoic acid receptor beta (RARbeta), and p16/INK4a. Pleural effusions were collected from 87 patients who had their diagnoses confirmed on cytologic and/or histologic examinations and clinical evolution. Pleural effusions were classified as malignant (n = 53 patients) or benign (n = 34 patients). RESULTS: Methylation was detected in serum from 45.3% of patients with malignant pleural effusions and from 0% of patients with benign pleural effusions, and it was detected in pleural fluid samples from 58.5% of patients with malignant pleural effusions and from 0% of patients with benign pleural effusions (P = .001). The sensitivity of MSP was greater than that of cytologic examination alone (39.1%; P = .001). When MSP was used together with cytologic examination, sensitivity increased to 69.8% (P = .001). CONCLUSIONS: Cell-free methylated DNA in pleural fluid can be detected in patients with neoplastic malignancy in a single extraction by thoracocentesis. Adequate management of the extracted pleural fluid can provide a rapid and reliable diagnosis in patients with pleural effusions who have suspected malignancy. MSP, used together with cytologic examination, may obviate the need for other invasive diagnostic tests.     

Diagnostic utility of CYFRA 21-1, carcinoembryonic antigen, CA 125, neuron specific enolase, and squamous cell antigen level determinations in the serum and pleural fluid of patients with pleural effusions.

BACKGROUND: To the authors' knowledge the role of tumor marker determination in the differential diagnosis of pleural effusions has not been established definitively. The current article reports the results of a study of CYFRA 21-1, carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), squamous cell antigen (SCC), and neuron specific enolase (NSE) in the serum and pleural fluid of patients with pleural effusions of diverse etiologies. METHODS: One hundred forty-six patients with pleural effusions (43 malignant, 47 tuberculous, 32 miscellaneous benign, and 24 paramalignant) were studied prospectively. Levels of CYFRA 21-1, CA 125, CEA, NSE, and SCC were measured by radioimmunoassay in the pleural fluid in all patients and in the serum in 118 patients. RESULTS: There were no significant differences between the serum and pleural fluid levels of tumor markers with the exception of CA 125, which was higher in the pleural fluid. With maximum specificity, the highest sensitivity in the diagnosis of pleural malignancy was obtained with a combination of CYFRA 21-1 (with a cutoff value of 150 U/L), CEA (with a cutoff value of 40 ng/mL), and CA 125 (with a cutoff value of 1000 ng/mL) in pleural fluid. NSE and SCC added no diagnostic value. The simultaneous use of tumor markers and cytology in pleural fluid increased the sensitivity from 55.8% to 81%. CONCLUSIONS: These findings suggest that a combination of CYFRA 21-1, CEA, and CA 125 in the pleural fluid can be a useful addition to pleural cytology in the diagnosis of malignant pleural effusion.     

Cell-free DNA concentration in pleural fluid and serum: quantitative approach and potential prognostic factor in patients with cancer and pleural effusions

PURPOSE: The presence of pleural effusions in patients with tumors is often indicative of locally advanced or metastatic disease, and detection of malignancy in effusion samples frequently leads to a disease upstaging. Our purpose was to quantify the DNA in pleural effusion and serum in patients presenting pleural effusion in order to assess the potential prognostic impact. PATIENTS AND METHODS: The DNA level was determined by amplifying hRNase P in paired samples of serum and pleural fluid in 70 consecutive patients with cancer showing pleural effusion. A group of 30 patients without cancer was included. The correlation between serum and pleural DNA was calculated. Survival curves according to serum and pleural DNA were analyzed. RESULTS: Median DNA concentrations were greater in patients with neoplasia than in patients without malignancy: 105 ng/mL versus 40 ng/mL (P = 0.001) in serum samples, respectively; 93 ng/mL versus 21 ng/mL (P = 0.001) in pleural fluids, respectively. A positive correlation between serum and pleural levels was confirmed (r = 0.3; P < 0.05). Median survival time for patients with serum DNA < or = 105 ng/mL was 11.03 months in contrast to only 3.63 months for patients with higher values (P = 0.036). Accordingly, median survival time for patients with pleural DNA < or = 93 ng/mL was 12.3 months versus only 4.63 months in case of higher levels (P = 0.027). CONCLUSION: This study shows that there is a strong correlation between higher levels of free DNA in pleural fluid or serum and malignancy. Survival is worse for patients with higher DNA levels in serum and pleural fluid.     

Tumor markers in pleural effusion diagnosis

In order to discriminate between malignant and benign effusions, the values of carcinoembryonic antigen (CEA), ferritin, beta2-microglobulin (BMG), acid-soluble glycoprotein (ASP), tissue polypeptide antigen (TPA), adenosine deaminase (ADA), and immunosuppressive acidic protein (IAP) were measured in the pleural fluid of 54 patients with lung cancer, 20 with malignancies other than lung cancer, 18 with tuberculous pleurisy, and 22 with benign diseases other than tuberculosis. CEA levels in malignant effusions were significantly higher than those in benign effusions. At a cutoff level of 5 ng/ml, 68% of the patients with lung cancer and 44% of the patients with other malignancies showed elevated pleural fluid CEA levels. In 13 lung cancer cases with negative pleural fluid cytology, nine cases had elevated pleural fluid CEA levels. The mean pleural fluid BMG level of patients with benign diseases was significantly higher than that of patients with malignant diseases, but there was a marked overlap between those with malignant and benign diseases. No significant differences were found in the pleural fluid ferritin, ASP, TPA, and IAP levels between malignant and benign conditions. ASP and IAP pleural fluid levels showed significant correlations with the pleural fluid C-reactive protein (CRP) concentrations suggesting that they also reflect inflammatory activity. The mean ADA activity in tuberculous effusion was significantly higher than that resulting from other causes of pleural effusion.     

High level of vascular endothelial growth factor in hemorrhagic pleural effusion of cancer

Angiogenic cytokines, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and angiogenin, are candidates for the induction of pleural effusions because they have been implicated in the induction of neovascularization, vascular permeability, and hemorrhage both in the inflammatory process and in tumor progression. Thus, we hypothesized that these angiogenic factors in effusion might be involved in the clinical manifestation of malignant pleural disease. We measured the levels of VEGF, bFGF, and angiogenin in pleural effusions and sera from 40 patients. Pleural effusions due to malignancy (1,350 pg/ml) contained significantly higher levels of VEGF than effusions due to inflammatory diseases (102 pg/ml; p = 0.034). Furthermore, hemorrhagic effusions showed significantly higher VEGF levels (1,942 pg/ml) than non-hemorrhagic effusions (202 pg/ml; p = 0.016) in malignant patients. In contrast, neither bFGF nor angiogenin were correlated with any clinical manifestation of pleural effusion. Immunohistochemical study revealed that malignant cells in the pleura were stained with anti-VEGF antibody. Our data suggest that VEGF secreted from tumor cells may be involved in the accumulation of pleural effusion in malignancy, and that increased levels of VEGF may induce hemorrhagic effusion.     

腺苷脱氨酶与癌胚抗原在恶性胸腔积液的诊断价值

测定了３８例恶性胸腔积液及３４例结核性胸水的腺苷脱氨酶（ＡＤＡ）与癌胚抗原（ＣＥＡ）在胸水、血清中水平及胸水／血清值。结果恶性组胸水ＡＤＡ值明显低于结核组（Ｐ＜０．０００５），ＡＤＡ胸水／血清值低于结核组（Ｐ＜０．０００５）；恶性组胸水ＣＥＡ水平明显高于结核组（Ｐ＜０．０００５），ＣＥＡ胸水／血清值恶性组亦明显高于结核组（Ｐ＜０．０５）。胸水ＡＤＡ水平对诊断恶性胸腔积液的敏感性为９６．１５％，符异性９１．６７％；ＣＥＡ的敏感住７０．８３％，特异性为８７．５０％。综合分析胸水的ＡＤＡ、ＣＥＡ水平及胸水／血清值，有助于对恶性胸腔积液的诊断。     

Microsatellite DNA analysis does not distinguish malignant from benign pleural effusions

Distinguishing malignant from benign pleural effusions using routine cytology is a common diagnostic problem. Recently, genetic alterations, including microsatellite instability (MSI) and loss of heterozygosity (LOH), have been described in malignant pleural effusions and proposed as methods improving diagnostics. The purpose of this study was to evaluate a panel of molecular markers for the detection of genetic alterations of cells in pleural effusions and to determine their diagnostic value as an additional test to cytologic examination. Pleural fluid and peripheral blood from 48 patients (36 male and 12 female, median age 71 years) were analyzed. Twenty-six patients had malignant pleural effusion, including 23 lung cancer and three metastatic non-pulmonary carcinoma. The control group consisted of 22 patients with benign pleural effusions. Only 14 malignancy-associated pleural effusions were cytology-positive for malignant cells (54%), whereas all benign pleural effusions were negative. DNA was extracted from all the samples and analysed for MSI and/or LOH using the following microsatellite markers: D3S1234, D9S171, D12S363, D17S250, D5S346 and TP53Alu, located at five chromosomal regions: 3p, 9p, 12q, 17q, 5q. Microsatellite analysis of the pleural fluid pellet exhibited genetic alterations in two neoplastic pleural fluid cases and in one inflammatory case. Two out of 26 (7.6%) patients with malignant pleural effusion showed genetic alterations. One exhibited MSI in three different microsatellite markers (D17S250, D9S171, D3S134) and the other showed LOH in marker D3S134. One out of 22 (4.5%) patients with benign pleural effusion showed LOH in marker D3S134. In conclusion, genetic alterations at the level of microsatellite DNA, were detected only in very few cases of malignant pleural effusions, and in one case of benign pleural effusion. Thus, our data suggest that microsatellite DNA analysis does not facilitate the diagnosis of malignant pleural effusion.     

Diagnostic Significance of Cancer Antigen 125, Pancreatic Oncofetal Antigen, and Carcinoembryonic Antigen in Malignant and Tuberculous Pleural Effusions

Pleural fluid levels of cancer antigen 125 (CA 125), pancreaticoncofetal antigen (POA), and carcinoembryonic antigen (CEA)were determined in 56 patients with malignant pleural effusionand in 35 patients with tuberculous effusion. Malignant effusionshad significantly higher pleural fluid CA 125 and CEA levelsthan those of tuberculous origin (p < 0.005). No significantdifference in POA titers was found between the two kinds ofeffusion. Assays of CA 125 and CEA in pleural fluid may be usefulin separating malignant from tuberculous effusions. Concurrentmeasurement of CA 125 and CEA proved superior to determinationof CEA alone in discriminating between the two groups.     

Diagnostic value of CEA, CA 15-3, CA 19-9, CYFRA 21-1, NSE and TSA assay in pleural effusions

The aim of this study was to evaluate the individual and combined diagnostic utility of six tumor markers in patients with pleural effusion. Pleural and serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 15-3 (CA 15-3), carbohydrate antigen 19-9 (CA 19-9), cytokeratin fragment 19 (CYFRA 21-1), neuron-specific enolase (NSE) and total sialic acid (TSA) were assayed in 74 patients with pleural effusions (44 malignant and 30 benign). All tumor markers except TSA and NSE were increased in both serum and pleural fluid of patients with malignant diseases. Using the cut-off values 3 ng/ml, 14 U/ml, 5 U/ml, 8 ng/ml and 70 mg/dl for pleural fluid CEA, CA 15-3, CA 19-9, CYFRA 21-1 and TSA, respectively, the sensitivity (%) and specificity (%) of these tumor markers were as follows: CEA; 52/77, CA 15-3; 80/93, CA 19-9; 36/83, CYFRA 21-1; 91/90, TSA; 80/67, for differentiating malignant effusions from benign. When CA 15-3 and CYFRA 21-1 combined, the sensitivity and specificity were increased (100 and 83%, respectively). Classifying the malignant effusions as bronchial carcinoma and malignant pleural mesothelioma, CEA was shown to have the highest sensitivity and specificity (88 and 90%, respectively) while the combination of CEA with other tumor markers increased sensitivity but decreased specificity. According to our results, tumor markers are not suitable for the differential diagnosis of malignancy.     

Clinical evaluation of four tumor markers in malignant and benign pleural effusions.

Total sialic acid (TSA), lipid-bound sialic acid (LSA), ferritin and carcinoembryonic antigen (CEA) were evaluated in 55 patients with malignant pleural effusions and in 32 patients with benign (exudative) pleural effusions. No significant differences were found in the pleural fluid TSA, LSA and ferritin levels between malignant and benign conditions. CEA levels in malignant effusions were significantly higher than those in benign effusions (43.13 +/- 72.8 ng/ml versus 2.6 +/- 5.56 ng/ml, p less than 0.01). At a cut-off level of 5 ng/ml, 60% of the patients with cancer showed elevated pleural fluid CEA levels. The specificity and diagnostic accuracy of CEA in distinguishing malignant from benign pleural exudates were both very high (91% and 71% respectively). Therefore, of the four markers investigated, only CEA could be a valuable tool in the detection of pleural malignancy.     

Diagnostic value of tumor markers for differentiating malignant and benign pleural effusions of Iranian patients

In order to evaluate the diagnostic yield of tumor markers in differentiating malignant and benign pleural effusions, we carried out a prospective study in a group of Iranian people. Pleural and serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 15-3 (CA15-3), neuron-specific enolase (NSE) and cancer antigen 125 (CA 125) were assayed prospectively in patients with pleural effusion (40 malignant and 37 benign). The highest sensitivity was obtained with a combination of CA 15-3 in serum, and CA 15-3 and CEA in pleural fluid (80%), also with combination of CA 15-3 in serum, and CA 15-3, NSE and CEA in pleural fluid (80%). The highest specificity was obtained with combination of CA 15-3 in serum, and CA 15-3 and NSE in pleural fluid (100%), and also with combination of CA 15-3 in serum, and CA 15-3, NSE and CEA in pleural fluid (100%).     

Carcinoembryonic antigen in pleural effusions. Diagnostic value in malignant mesothelioma

The usefulness of the determination of carcinoembryonic antigen (CEA) in pleural effusion was assessed as an aid to the diagnosis of malignant mesothelioma. The concentration of CEA was determined by radioimmunoassay (RIA) in pleural fluid of 213 adult patients, of which 140 had malignant pleural disease and 73 had nonmalignant pleural disease. Pleural fluid CEA (PF CEA) was lower than 12 ng/ml in all 15 mesotheliomas. The statistical probability of a mesothelioma associated with PF CEA greater than 15 ng/ml was found to be zero. The CEA assay in pleural effusion proved to be a valuable adjunct to other diagnostic procedures in differentiating the malignant mesothelioma from metastatic serosal spread.     

Evaluation of pleural CYFRA 21-1 and carcinoembryonic antigen in the diagnosis of malignant pleural effusions.

CYFRA 21-1 assay, measuring cytokeratin 19 fragments, was compared with carcinoembryonic antigen (CEA) assay, as an addition to cytological analysis for the diagnosis of malignant effusions. Both markers were determined with commercial enzyme immunoassays in pleural fluid from 196 patients. Cytological analysis and/or pleural biopsy confirmed the malignant origin of the effusion in 99 patients (76 carcinomas, nine pleural mesotheliomas and 14 non-epithelial malignancies). Effusions were confirmed as benign in 97 patients (33 cardiac failures, 39 infectious diseases--including 12 tuberculosis-- and 25 miscellaneous effusions). Both markers were significantly higher in malignant than in benign effusions. All the patients with non-epithelial malignancies presented CYFRA and CEA values lower than the 95% diagnostic specificity thresholds (100 and 6 ng ml(-1) respectively). The diagnostic sensitivity in the group of carcinomas and mesotheliomas was similar for CYFRA (58.8%) and CEA (64.7%). However, CEA had a significantly higher sensitivity in carcinomas (72.4% vs 55.3%), while CYFRA had a clearly higher sensitivity in mesotheliomas (89.9% vs 0%). Interestingly, 12 out of the 16 malignant effusions with a negative cytology were CEA and/or CYFRA positive. Regarding their high diagnostic sensitivity and their complementarity, CEA and CYFRA appear to be very useful for the diagnosis of malignant pleural effusions when cytology is negative.     

Malignant pleural effusions in lymphoproliferative disorders

In order to determine variables that correlate with malignant pleural effusion and mortality in patients with lymphoproliferative disorders and pleural effusion, a retrospective study was performed. Clinical data of hospitalized patients with a lymphoid malignancy and pleural effusion who underwent thoracentesis from January 1993 to December 2002 were collected. A logistic regression analysis was carried out to determine prognostic variables that predict malignant pleural effusion and hospital mortality. There were 86 patients who were admitted on 91 occasions. The median age was 70 years (range 4 - 92) and the male:female ratio was 44:42. Sixty-four patients (74%) had advanced disease, 43 (50%) had received prior chemotherapy and 9 (10%) were in remission. Of 91 cases of pleural effusions, 44 (48%) were bilateral, 80 (88%) were exudates and 48 (53%) were due to malignant involvement of pleura. In multivariate analysis, symptomatic pleural effusion (odds ratio 10.3, 95% confidence interval 1.7 - 98.3), pleural fluid mesothelial cell count < 5% (odds ratio 8.0, 95% confidence interval 1.4 - 58.2), pleural fluid:serum lactate dehydrogenase (LDH) > or =1 (odds ratio 6.4, 95% confidence interval 1.2 - 45.6) and pleural fluid lymphocyte percentage > or =50 (odds ratio 6.4, 95% confidence interval 1.2 - 50) were significantly correlated with malignant effusion. A secondary cancer (odds ratio 11.9, 95% confidence interval 2.3 - 88.8), pleural fluid:serum LDH > or =1 (odds ratio 10.9, 95% confidence interval 2.6 - 64.9), and pneumonia (odds ratio 6.4, 95% confidence interval 1.7 - 28.6) were significantly correlated with hospital mortality. In conclusion, malignant pleural effusion is the common etiology of pleural effusion in patients with lymphoid malignancy. Many clinical and cytochemical markers have discriminatory values in identifying malignant effusion. A high pleural fluid to serum LDH level correlates with malignant pleural involvement and hospital mortality.     

DNA倍体联合肿瘤标志物检测在胸腔积液诊断中的应用

目的探讨DNA倍体分析联合肿瘤标志物在良、恶性胸腔积液诊断中的价值。方法将108例胸腔积液分为恶性组（68例）和良性组（40例）。除常规细胞学检查外,以流式细胞术（flowcytometry,FCM）检测患者胸腔积液中的DNA倍体,采用化学发光法测定胸腔积液中CEA、CA199、NSE、CYFRA211、SCC、CA125等肿瘤标志物含量。比较DNA倍体联合肿瘤标志物诊断与细胞学诊断的优劣。结果DNA倍体诊断恶性胸腔积液的敏感性、特异性分别为70．6％、95．0％,Youden’s指数为0．656,敏感度稍高于细胞学诊断的65．1％,差异无统计学意义（P〉0．05）。除NSE外,其他5种肿瘤标志物在恶性胸腔积液中浓度均高于良性,差异有统计学意义（P〈0．05）。CYFRA211、CEA、CAl99、CAl25、SCC、NSE的AUC分别为：0．893,0．828,0．759,0．691,0．524及0．490;COV分别为：149．2ng／mL,53．6ng／mL,78．2IU／mL,1559．0IU／mL,48．72ng／mL及78．3ng／mL;敏感性分别为：44．1％,44．1％,35．3％,29．4％,13．2％,5．9％,特异性均为100％。4种肿瘤标志物联合检测＋DNA倍体检测的敏感性为88．2％（60／68）,特异性95％,显著高于细胞学诊断。结论DNA倍体联合CEA、CA199、CYFRA211和CA125检测诊断恶性胸腔积液有较高敏感性,具有定量、快速、价廉、易标准化的特点,且操作简单。     

Aberrant promoter methylation in pleural fluid DNA for diagnosis of malignant pleural effusion

Accumulating evidence implicates epigenetic changes such as hypermethylation in carcinogenesis. We investigated whether DNA methylation of 5 tumor suppressor genes in pleural fluid samples could aid in diagnosis of malignant effusion. In samples from 47 patients with malignant pleural effusions and 34 with nonmalignant effusions, we used a methylation-specific polymerase chain reaction to detect aberrant hypermethylation of the promoters of the DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT), p16(INK4a), ras association domain family 1A (RASSF1A), apoptosis-related genes, death-associated protein kinase (DAPK), and retinoic acid receptor beta (RARbeta). Promoter hypermethylation was associated with malignant effusion for MGMT (Odds ratio (OR) = infinity), p16(INK4a) (OR = infinity), RASSF1A (OR = 13.8; CI, 1.71-112), and RARbeta (OR = 3.17; CI, 1.10-9.11), but not for DAPK. Instead, DAPK methylation was associated with the length of smoking (p < 0.05). Patients with hypermethylation of MGMT, p16(INK4a), RASSF1A or RARbeta were 5.68 times more likely to have malignant effusions than patients without methylation (p = 0.008). Methylations per patient were more numerous for lung cancer than nonmalignant pulmonary disease (0.915 vs. 0.206, p < 0.001). Sensitivity, specificity, and positive predictive value of methylation in one or more genes for diagnosis of malignant effusion were 59.6%, 79.4%, and 80.0% respectively. In conclusion, aberrant promoter methylation of tumor suppressor genes in pleural fluid DNA could be a valuable diagnostic marker for malignant pleural effusion.     

Ratios of pleural fluid to serum immunoglobulins in malignant pleural effusions

Pleural fluid and serum protein electrophoresis and quantitative immunoglobulin measurements were carried out in patients with pleural effusions. The mean pleural fluid/serum ratios of IgA, IgG, and IgM were elevated in patients with malignant pleural effusions compared with patients with nonmalignant pleural effusions (P less than 0.04). The sensitivity of a pleural/serum IgA, IgG ratio P greater than 0.6 was 46%, 69%, respectively, and for IgM ratio greater than 0.5 was 28%. The specificity for these same ratios was 89%, 74%, and 100% respectively.