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Department of Medicine, McLean Hospital, Belmont, MA; Clinical Laboratory and Nuclear Medicine Divisions, Massachusetts General Hospital and Harvard Medical School, Boston, MA ********** In contrast to nonspecific elevations of myoglobin [...]

BACKGROUND: Cystic lesions of the pancreas include inflammatory pseudocysts, serous cystadenomas, and mucinous cystic tumors, some of which are malignant. Previous studies have shown that malignant mucinous tumors differ from benign pancreatic cysts in proliferative activity, secretion of tumor markers, and expression of growth factor receptors. Analysis of aspirated cyst fluid for tumor markers, viscosity, and cytologic examination has been proposed as an aid to preoperative differential diagnosis. Tissue polypeptide antigen (TPA) is a soluble proliferation antigen produced by rapidly dividing tissues, including conventional ductal pancreatic carcinoma. TPA levels in pancreatic cyst fluids have not been reported. METHODS: Tissue polypeptide antigen levels were determined in 46 pancreatic cyst fluids using a commercial immunoassay technique. RESULTS: Mucinous cystadenocarcinomas exhibited significantly higher levels of cyst fluid TPA than benign cystic lesions, including pseudocysts, serous cystadenomas, and benign mucinous cystadenomas (mean 910,672 U/mL, median 300,900 U/mL, range 16,600 to 4,210,000 U/mL for malignant mucinous cystadenocarcinomas; versus mean 16,082 U/mL, median 2,455 U/mL, range 0 to 155,000 U/mL for benign cystic lesions considered as a group; P

Acinar necrosis in patients with acute pancreatitis can be due to enzymatie injury, ischemia, or both. We hypothesized that novel therapy aimed at an improvement of pancreatic microcirculation early in the course of pancreatitis may reduce the lethality and aeinar damage. Forty-six dextran-resistant rats received controlled intraductal infusion of glycodeoxycholic acid (10 mmol/L), followed by intravenous cerulein ( 5 [micro]g/kg/h) for 6 hours. Beginning 30 minutes after the induction of pancreatitis, all animals were resuscitated with Ringer's lactate (RL) (8 mL/kg/h intravenously for 9 hours . In addition, they were given intra-aortic bolus infusions (2 mL/kg at 30, 60, 90, and 150 minutes) of either RL, sodium chloride (NaCI) (7.5%) and dextran 60,000 (10%) (HHS-60), NaCI (7.5%) and dextran 500,000 (10%) (HHS-500), or NaCl (0.9%) and dextran 500,000 (10%) (DEX-500). Despite high-volume fluid resuscitation in the group that received RL and HHS-60, 70% of the animals in each of these groups died within 24 hours. In contrast, the mortality rates in the groups of animals that received HHS-500 and DEX-500 were dramatically reduced to 0% and 10%, respectively (p= 0.005, p = 0.02). Histopathologic scores for aeinar necrosis were significantly lower in the group of animals that received DEX-500 (p Rapid bolus infusion of hyperoncotic ultra-high molecular weight dextran solution with or without hypertonic saline but not RL or hypertonic-hyperoneotic saline-dextran significantly reduced pathologic trypsinogen activation, prevented acinar necrosis, and improved survival in acute experimental pancreatitis. We speculate that a sustained improvement of pancreatic microcirculation by ultrahigh molecular weight dextran is the mechanism of action.

Medullary carcinoma of the breast is a fairly rare subtype of infiltrating ductal carcinoma with a more favorable prognosis than the more common forms of invasive breast cancer. However, it seems likely that medullary carcinoma is overdiagnosed, leading to less aggressive treatment than is warranted for the cancer that really exists. A review of all breast cancer cases diagnosed at Massachusetts General Hospital in Boston over a 10-year period is provided. Tumors were classified as typical or atypical medullary carcinoma (TMC, AMC), or nonmedullary carcinoma (NMC), according to their growth patterns and cellular characteristics. Results showed that only nine of the 30 cases originally diagnosed as medullary carcinoma actually fit the criteria for TMC. Seven were reclassified as AMC, and 14 as NMC. Of the latter group, 13 were infiltrating ductal carcinomas, and one was squamous cell carcinoma. Tumors for which information regarding estrogen-receptor status was known were all negative (tumor cells can be positive or negative for their receptivity to estrogen, a female hormone). Six patients with TMC had undergone mastectomy as the only treatment. Three were alive and well after at least three years, one developed metastases, and two were lost to follow-up. The remaining three TMC patients received more aggressive treatment and were alive and well. The AMC patients in this series also received aggressive treatment, and, of the five who were followed-up, two died with metastases. Results from other studies are reviewed which show, in general, improved survival for patients with typical medullary cancer. The reasons for this are not known since, in fact, some characteristics of this kind of cancer (such as its lack of estrogen receptors) are usually associated with a poorer prognosis. In summary, medullary cancer appears to be overdiagnosed, a situation that should be kept in mind by the physician when diagnosis is made. (Consumer Summary produced by Reliance Medical Information, Inc.)

Department of Medicine, McLean Hospital, Belmont, MA; Beth Israel Deaconess Medical Center, Boston, MA; Massachusetts General Hospital and Brigham and Women's Hospital, Boston, MA; Royal North Shore Hospital, Sydney, Australia; [...]

Background: Mechanisms that mediate cocaine-induced cardiovascular events following vasoconstriction are incompletely understood. Objective: To examine the effects of cocaine in moderate doses on hematologic and hemostatic parameters that influence blood viscosity and thrombotic potential. Methods: Changes in hemoglobin concentration, hematocrit, and red blood cell counts were measured in human subjects who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for long-term cocaine abuse, before and sequentially after moderate intranasal and intravenous doses of cocaine. Hemostatic parameters, including von Willebrand factor, fibrinolytic activity, fibrinogen, plasminogen activator inhibitor antigen, and tissue-type plasminogen activator antigen, were sequentially measured after intravenous cocaine or saline placebo with cardiac troponin subunits T and I. Results: Hemoglobin level (P = .002), hematocrit (P = .01), and red blood cell counts (P = .04) significantly increased from 4% to 6% over baseline from 10 to 30 minutes after intranasal (n = 14) and intravenous (n = 7) cocaine administration in doses of 0.9 mg/kg and 0.4 mg/kg, respectively, with no change in white blood cell or platelet counts. There was a significant increase (P = .03) in von Willebrand factor from 30 to 240 minutes, peaking at 40% over baseline following intravenous cocaine administration in a dose of 0.4 mg/kg (n = 12), with no change after 0.2 mg/kg (n = 3) or placebo (n = 6). Other hemostatic factors, creatinine, blood urea nitrogen, and cardiac troponin subunits T and I showed no changes. Conclusions: Cocaine induced a transient erythrocytosis that may increase blood viscosity while maintaining tissue oxygenation during vasoconstriction. An increase in von Willebrand factor without a compensatory change in endogenous fibrinolysis may trigger platelet adhesion, aggregation, and intravascular thrombosis. Arch Intern Med. 1999;159:1925-1930

Inaccurate glucose results from applying insufficient blood to the test strips is a common problem. It has been reported that up to 30% of patients have difficulty obtaining an adequate [...]

The National Academy of Clinical Biochemistry (NACB) has developed clinical practice guidelines for occult blood testing. Annual or biennial guaiac-based fecal occult blood testing (FOBT) should be performed in average-risk asymptomatic patients older than 50 years to reduce mortality from colorectal cancer (CRC). Although the current literature is insufficient to favor central laboratory FOBT over point-of-care testing, experts do not recommend performing testing that screens for CRC at the point of care. Home collection of specimens with analysis either in the physician's office or laboratory is recommended. Either guaiac-based or immunologic methods can be used, but more evidence is necessary to recommend the preferred methodology. Occult blood testing is frequently used in the hospital setting for purposes other than CRC screening. According to the literature, other applications of occult blood testing are controversial. The utility of FOBT to detect gastrointestinal bleeding and assess bleeding risk in patients on anticoagulation is questionable. Intensive care unit patients may benefit from gastroccult testing to detect gastric bleeding, but no large studies have been performed to demonstrate improved outcomes.

Emergency department (ED) overcrowding and prolonged patient length of stay (LOS) is an increasing problem in most American hospitals. Some reports in the literature have suggested that point-of-care (POC) testing may help alleviate ED overcrowding by providing rapid test results to aid in triage decisions and administration of appropriate therapy. In our hospital, a limited menu of POC tests was shown to decrease ED LOS and reduce the number of hours the ED was on divert status. In recent years, the menu of tests available in POC formats has continued to expand raising the possibility that more patients could receive rapid POC results and potentially have a greater impact on ED operations. We analyzed ED laboratory test ordering patterns to determine what impact an expansion of the ED POC menu might achieve using a selected group of instruments. The ED at Massachusetts General Hospital evaluated approximately 76,000 patients in 2005, of which 25% are admitted. Of these, approximately 76% received laboratory testing. The average number of tests per patient for those that received testing was 7.7 assuming scoring of standard medicare panels as one test for the panel, and 75% of patients had 5 or more tests/panels ordered. Of tests performed in our ED, 9% are now performed at the POC in our satellite laboratory (blood glucose, cardiac markers, dipstick urinalysis, urine pregnancy testing, and rapid Strep A and influenza testing) and 66% of patients that receive testing have some test performed at the POC. Overall, the most common laboratory tests requested are the basic metabolic panel (15.0% of tests), complete blood count (13.2%), calcium/phosphate/magnesium (9.7%), hepatic panel (6.7%), urinalysis (6.2%), cardiac markers (5.2%), prothrombin time (5.1%), amylase/lipase (4.8%), urine pregnancy (4.1%), toxicology (2.9%), and partial thromboplastin time (2.8%), respectively. Of patients that received testing, 88% had a complete blood count; 86%, a basic metabolic panel; 68%, a calcium/phosphate/magnesium; 58%, a hepatic panel; 47%, a urinalysis; 39%, a prothrombin time; 36%, an amylase/lipase; 32%, a urine pregnancy; 28%, cardiac markers; and 2.1%, a toxicology analysis. Of all tests, 71.6% were chemistries, 23.4% were hematology tests, and 5% were microbiology tests. Using a hypothetical combination of a rapid chemistry analyzer, a conventional hematology cell counter, and other true POC testing devices, 75.6% of the tests requested by our ED could be performed in our satellite laboratory. With this menu, all requested testing could be performed on 62% of patients that receive testing. The remaining 38% would require some other additional test(s) to complete the laboratory evaluation.

The laboratory testing process, including the preanalytic, analytic, and postanalytic phases, is an area where errors frequently occur. These errors may impair the diagnostic process and compromise patient safety. Delay in diagnosis and failure to diagnose are common reasons for a medicolegal action. It is estimated that over 70% of medical decisions are made using laboratory data. For this reason, the laboratory is often involved either directly or indirectly in medical liability cases. The laboratory and hospital need to design systems that reduce the possibility of error and to rapidly identify and resolve the errors that do occur. Because the pre- and postanalytic processes extend into the clinical operations of the hospital, the laboratory can play an important role in promoting patient safety by assisting clinicians with test ordering, communicating test results appropriately, and aiding in the interpretation of results.

We report changes in cardiac troponin-T (TnT) and a new plasma stroke biomarker panel (D-dimer, B-natriuretic peptide [BNP], matrix metalloproteinase-9 [MMP-9], S-100 b, Biosite Diagnostics, San Diego, CA) in 30 nonprofessional marathon runners before and immediately after the 2005 Boston Marathon. Following competition, there was a statistically significant increase in MMP-9 (P < .001) and D dimer (P < .001). Nonsignificant changes in S-100 b and BNP were observed. Premarathon and postmarathon values for a multimarker stroke index increased from 0.97 (normal) to 3.5 (low risk or more; P < .001). Two subjects had index values more than the high-risk cutoff value. Mean TnT premarathon and postmarathon levels increased (from <0.01 to 0.03 ng/mL; P < .0001). After the marathon, with a cutoff value of 0.05 ng/mL, 7 runners (23%) had values above the manufacturer's recommended cutoff for myocardial damage. Although biochemical evidence of myocardial damage following strenuous exercise may reflect myocardial stunning or subclinical ischemia, the changes in the stroke index and values for individual stroke markers may reflect a systemic inflammatory response to exertional rhabdomyolysis which is common, but the possibility of subclinical central nervous system damage cannot be excluded.

HYPOTHESIS Drotrecogin alfa (activated), the pharmacologic form of activated protein C and the first Food and Drug Administration–approved drug for treatment of severe sepsis, is beneficial in experimental acute pancreatitis (AP). DESIGN Animal study. SETTING Laboratory. SUBJECTS Male Sprague-Dawley rats. INTERVENTIONS Mild (intravenous cerulein) or severe (intravenous cerulein plus intraductal glycodeoxycholic acid) AP was induced in 72 rats, and coagulation evaluated. Rats with severe AP were randomized to treatment with drotrecogin alfa (activated), 100 μg/kg per hour, or isotonic sodium chloride. MAIN OUTCOME MEASURES Histologic scoring of pancreatic necrosis, inflammation of the pancreas and lung (measured by myeloperoxidase concentration), coagulation measures, and 24-hour survival. RESULTS Severe consumptive coagulopathy, hemoconcentration, and leukocytosis were observed 6 hours after induction of severe AP, but not in mild AP. Treatment of AP with drotrecogin did not worsen coagulation measures. Although the degree of pancreatic necrosis was comparable in treated and untreated animals with severe AP, drotrecogin significantly reduced myeloperoxidase levels in the pancreas (P = .009) and lungs (P = .03). The 24-hour survival in severe AP was markedly improved in animals treated with drotrecogin (86% vs 38%; P = .05). CONCLUSIONS Animals with severe AP have severe consumptive coagulopathy, but administration of drotrecogin alfa (activated), 100 μg/kg per hour, does not worsen coagulation abnormalities. Drotrecogin treatment reduces inflammation in the pancreas and lungs and significantly improves survival. These results encourage clinical investigation of drotrecogin in the treatment of severe AP.Arch Surg. 2006;141:670-676--

Reporting of laboratory critical values has become an issue of national attention as illustrated by recent guidelines described in the National Patient Safety Goals of the Joint Commission on Accreditation of Healthcare Organizations. Herein, we report the results of an analysis of 37,503 consecutive laboratory critical values at our institution, a large urban academic medical center. We evaluated critical value reporting by test, laboratory specialty, patient type, clinical care area, time of day, and critical value limits. Factors leading to delays in critical value reporting are identified, and we describe approaches to improving this important operational and patient safety issue.

We evaluated the CellaVision DM96 (CellaVision AB, Lund, Sweden), an automated digital cell morphology and informatics system for peripheral blood smears. Technologists agreed with 82% of the instrument's preclassifications. Correlation coefficients between final results released from the CellaVision and results obtained by direct microscopy were 0.96 (all neutrophils), 0.94 (lymphocytes), 0.88 (segmented neutrophils), 0.73 (eosinophils), 0.69 (bands), and 0.67 (monocytes). After correction for statistically and clinically insignificant variations, the CellaVision DM96 had 95% sensitivity and 88% specificity for immature myeloid cells. It was 100% sensitive and 94% specific for blasts, and 100% sensitive and 97% specific for unusual WBCs and nucleated RBCs. Advantages of the CellaVision DM96 over direct microscopy include the ability to review slides from a remote location, consultation and quality control on a cell-by-cell basis, and potential labor savings.

We studied the role of ischemia-modified albumin (IMA) with standard biomarkers (myoglobin, creatine kinase-MB [CK-MB], troponin I [TnI]) in assessment of 200 patients with suspected myocardial ischemia admitted to the emergency department. Every case was reviewed by a cardiologist. A clinical diagnosis of ischemia was assigned and correlated with biomarker test results. Of the patients, 25 (13.0%) had myocardial ischemia. Receiver operating characteristic curves demonstrated IMA as highly sensitive but somewhat poorly specific for the presence of ischemia (area under curve, 0.63; P = .01). With a cut point of 90 U/mL, the Albumin Cobalt Binding Test had 80% sensitivity and 31% specificity for diagnosing ischemia and a negative predictive value of 92%. IMA was positive in 4 of 5 patients with electrocardiographic (ECG) evidence of ischemia and 16 of 20 patients with coronary ischemia but negative ECG. Among the same patients, the myoglobin-CK-MB-TnI triad had a sensitivity of 57%. The combination of IMA-myoglobin-CK-MB-TnI increased the sensitivity for detecting ischemia to 97%, with a negative predictive value of 92%. IMA is highly sensitive and has a high negative predictive value, which might improve the usefulness of standard biomarkers of myocardial ischemia.

Myoglobin is an early marker of cardiac injury, although positive results occur in the absence of cardiac myonecrosis. We studied data for 537 patients admitted to the emergency department with symptoms suggestive of myocardial injury who underwent testing for troponin I (TnI), creatine kinase isoenzyme (CK-MB), and myoglobin at the point of care. Physicians were blinded to the myoglobin results. Myoglobin had a sensitivity of 69.7% and a negative predictive value of 97.4% for the diagnosis of acute coronary syndrome (ACS) on "first-draw" specimens. Receiver operating characteristic curve analysis suggested that myoglobin demonstrated optimal sensitivity for ACS, while TnI had optimal specificity. CK-MB was neither the most specific nor the most sensitive marker. More than 80% of the patients with false-positive myoglobin results were admitted to the hospital. These data invalidate concerns regarding the putative overtreatment effect of false-positive cases owing to myoglobin results. Furthermore, our data suggest that myoglobin is superior to CK-MB as an adjunct to TnI.

Participants in marathon races may require medical attention and the performance of laboratory assays. We report the changes in basic biochemical parameters, cardiac markers, CBC counts, and WBC differentials observed in participants in a marathon before, within 4 hours, and 24 hours after a race. The concentrations of glucose, total protein, albumin, uric acid, calcium, phosphorus, serum urea nitrogen, creatinine, bilirubin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, total creatine kinase, creatine kinase-MB, myoglobin, and the anion gap were increased after the race, consistent with the effects of exertional rhabdomyolysis and hemolysis. The increase in WBC counts was due mainly to neutrophilia and monocytosis, with a relative decrease in circulating lymphocytes, consistent with an inflammatory reaction to tissue injury. A significant percentage of laboratory results were outside the standard reference ranges, indicating that modified reference ranges derivedfrom marathon runners might be more appropriatefor this population. We provide a table of modified reference ranges (or expected ranges) for basic biochemical, cardiac, and hematologic laboratory parameters for marathon runners.

We evaluated a new point-of-care (POC) device for urine drugs of abuse (DOA) screening including appropriate clinical interpretation and potential benefits in a large academic medical center. Two hundred consecutive urine samples were tested using Syva Rapid Test (SRT) and existing laboratory methods (Syva EMIT II). Agreement between methods was acceptable with some considerations. Threshold concentration differences, drug interferences, and cross-reactivity profiles of the class-specific assays resulted in performance differences between the POC and central laboratory methods. Clinical interpretation of POC results requires an understanding of these issues as well as the limitations of urine testing. While urine-based screening is used in workplace testing and in a variety of clinical applications, quantitative blood measurements of some drugs (e.g. ethanol, acetaminophen, salicylate, ±tricyclic antidepressants) will remain important in the emergent setting. Performance of the SRT method takes approximately 10 min. Consequently, the major advantage over laboratory methods is rapid turnaround time. At the Massachusetts General Hospital, the most important application is for samples from the emergency department (about 1700/year). Each institution should assess its own needs and capabilities with regard to POC versus laboratory-based testing for DOA.

Contrast-enhanced computed tomography (CECT) is used to show areas of decreased pancreatic perfusion in severe acute pancreatitis (AP). To evaluate possible adverse effects of the contrast medium (CM) on the course of AP, the impact of intravenous CM in AP of graded severity in the rat was studied.

OBJECTIVE: To evaluate the role of epidermal growth factor receptor (EGF-R) and pS2 protein in the evolution of malignancy in mucinous cystic tumors of the pancreas. BACKGROUND: Mucinous cystic tumors of the pancreas include histologically benign but premalignant mucinous cystic neoplasms and mucinous cystadenocarcinoma. The molecular events leading to transformation from a benign to a malignant mucinous tumor are not known. Overexpression of EGF-R and detection of an estrogen-induced protein (pS2) has been demonstrated in ductal adenocarcinomas of the pancreas, but these factors have not been evaluated in mucinous cystic tumors. DESIGN: Twenty-six mucinous tumors were examined for EGF-R, pS2 protein, and estrogen and progesterone receptors. RESULTS: Eight (61.2%) of 13 malignant tumors exhibited increased expression of EGF-R, whereas EGF-R was not detected in any of the 13 benign tumors (P=.002). The pS2 protein was detected in nine of 11 malignant and 11 of 11 benign tumors (P=.480). Estrogen and progesterone receptors were not detected in the epithelium of either tumor type. The median survival time of the patients with EGF-R-negative tumors was 29.0 months compared with 14.5 months for those with EGF-R-postive tumors, but this difference did not reach significance owing to the small population size. CONCLUSIONS: Overexpression of EGF-R in mucinous cystic tumors, as in ductal adenocarcinomas, may be an important feature associated with malignancy and may have prognostic significance. Failure to detect EGF-R in histologically benign epithelium suggests that the upregulation of EGF-R may be important in the evolution of aggressive behavior. The expression of pS2 protein appears to be independent of estrogen and may play a role in the proliferative activity of mucinous tumors. However, pS2 expression is not a feature associated exclusively with malignancy.(Arch Surg. 1995;130:69-72)

OBJECTIVE: To evaluate the factors thought to be involved in the pathogenesis of acute pancreatitis associated with alcohol. BACKGROUND: The mechanism of alcohol-induced pancreatitis is believed to involve synergistic effects of various pathogenetic factors. The present study was designed to evaluate the possible contribution of pancreatic duct obstruction, physiologic exocrine stimulation, or secretory hyperstimulation to alcohol-induced pancreatic injury. METHODS: Wistar rats were allocated randomly to a control group (group 1), or to a group with pancreatic duct obstruction (group 2), physiologic exocrine stimulation (group 3), ductal obstruction and exocrine stimulation (group 4), or exocrine hyperstimulation with the cholecystokinin analogue cerulein (group 5). Three hours after this pretreatment, animals in each experimental group were randomly divided into two subgroups for intragastric administration of either water (groups 1A through 5A) or beer (groups 1B through 5B). Test solutions were instilled over 9 hours (total amount of alcohol administered, 4.8 g/kg). Twenty-four hours after beginning the test infusion, animals were killed for histologic evaluation of pancreatic edema and determination of an acinar cell necrosis score. Serum amylase levels were determined at 3, 9, and 24 hours. RESULTS: No increase in amylase levels or significant morphologic changes were found in control animals (group 1A) or in animals subjected to physiologic exocrine stimulation (group 2A). Pancreatic duct obstruction, with or without physiologic exocrine hyperstimulation (groups 3A and 4A), and exocrine hyperstimulation (group 5A) induced pancreatitis of similar severity with minor acinar cell damage. Alcohol superimposed on exocrine hyperstimulation (group 5B) increased acinar cell injury (group 5A, 0.4±0.1 points vs 5B, 1.0±0.2 points; P&lt;.05) and serum amylase levels at 24 hours (group 5a, 41±6 U/L vs group 5B, 72±11 U/L; P&lt;.05), whereas no differences between subgroups A and B (water vs beer) were found in groups 1 through 4. CONCLUSION: Our findings suggest that the pathogenesis of acute alcoholic pancreatitis may require a state of exocrine hyperstimulation, perhaps via cholecystokinin, but do not support a role for constriction or obstruction of Oddi's sphincter.(Arch Surg. 1994;129:1081-1085)

Cystic lesions of the pancreas include inflammatory pseudocysts, serous cystadenomas, and muci-nous tumors, some of which are malignant. Preoperative clinical and radiological parameters are unreliable and may result in incorrect diagnosis and inappropriate treatment. Cyst fluid analysis for cytology, viscosity, carcino-embryonic antigen, CA 72–4, and CA 15–3 will distinguish mucinous from nonmucinous lesions and usually help in determining malignancy. Currently, there is no reliable method to differentiate inflammatory pseudocysts from serous cystadenomas. This distinction is important because the treatment of these two lesions is different; pseudocysts are either observed or drained, whereas serous tumors are usually resected. The tumor marker NB/ 70K was measured in aspirated cyst fluid from 13 inflammatory pseudocysts and 11 serous cystadenomas by a commercial immunoassay. Leukocyte esterase was measured using Chemstrip SG urine test strips and amylase and lipase on a routine chemistry analyzer. The cyst fluid NB/70K concentration was significantly higher in pseudocysts (mean, 555 U/ml; range, 42–1,926 U/ml) than in serous cystadenomas (mean, 12 U/ml; range, 0–130 U/ml) and this difference was significant (p< 0.0002). Leukocyte esterase was detected in 7 of 11 pseudocysts but was absent in 10 of 10 serous tumors (p0.002). Amylase and lipase values were generally higher in pseudocysts but these markers were unreliable due to marked outliers. Cyst fluid NB/70K and leukocyte esterase are promising markers to help differentiate pseudocysts from serous tumors on percutaneous aspirates. When combined with previously reported cyst fluid parameters (amylase, lipase, cytology, and amylase isoenzymes), these two cystic lesions can be reliably distinguished.