Racial and insurance disparities among patients presenting with chest pain in the US: 2009-2015.

BACKGROUND: Nationally representative studies have shown significant racial and socioeconomic disparities in the triage and diagnostic evaluation of patients presenting to the emergency department (ED) with chest pain. However, these studies were conducted over a decade ago and have not been updated amidst growing awareness of healthcare disparities. OBJECTIVE: We aimed to reevaluate the effect of race and insurance type on triage acuity and diagnostic testing to assess if these disparities persist. METHODS: We identified ED visits for adults presenting with chest pain in the 2009-2015 National Hospital Ambulatory Health Care Surveys. Using weighted logistic regression, we examined associations between race and payment type with triage acuity and likelihood of ordering electrocardiography (ECG) or cardiac enzymes. RESULTS: A total of 10,441 patients met inclusion criteria, corresponding to an estimated 51.4 million patients nationwide. When compared with white patients, black patients presenting with chest pain were less likely to have an ECG ordered (adjusted odds ratio [OR] = 0.82, 95% confidence interval [CI] = 0.69-0.99). Patients with Medicare, Medicaid, and no insurance were also less likely to have an ECG ordered compared to patients with private insurance (Medicare: OR = 0.79, CI = 0.63-0.99; Medicaid: OR = 0.67, CI = 0.53-0.84; no insurance: OR = 0.68, CI = 0.55-0.84). Those with Medicare and Medicaid were less likely to be triaged emergently (Medicare: OR = 0.84, CI = 0.71-0.99; Medicaid: OR = 0.76, CI = 0.64-0.91) and those with Medicare were less likely to have cardiac enzymes ordered (OR = 0.84, CI = 0.72-0.98). CONCLUSIONS: Persistent racial and insurance disparities exist in the evaluation of chest pain in the ED. Compared to earlier studies, disparities in triage acuity and cardiac enzymes appear to have diminished, but disparities in ECG ordering have not. Given current Class I recommendations for ECGs on all patients presenting with chest pain emergently, our findings highlight the need for improvement in this area.

[Prevalence and risk factors of drug induced liver disease: a survey based study in pharmacies]. / Häufigkeit und Risikofaktoren medikamentös-toxischer Leberschäden: eine umfragebasierte Studie in Apotheken.

AIM: The reported incidence of drug-induced liver injury (DILI) ranges from 1 in 10,000 to 1 in 100,000 patients for most drugs, but the true incidence is expected to be much higher. Several risk factors for DILI susceptibility have been suggested, however there is insufficient data to define an individual risk profile. Therefore it was our aim to study the prevalence of DILI and potential risk factors within adult pharmacy customers in Germany. METHODS: We conducted two 6 week-survey studies in 30 pharmacies in 2011 and 2012, respectively, using a newly developed questionnaire comprising questions on demography, (liver) diseases, liver enzyme activities, and drug history. In each study, anonymized questionnaires were presented to non-selected adult customers taking (non-)prescription drugs. RESULTS: Combining the datasets from the 2011 and 2012 surveys, in total 1098 questionnaires were evaluated (mean age 57.7 ±â€Š17.1 years; 62.6 % females, return rate 15.25 %). Overall, 141 individuals (12.8 %) reported elevated liver enzymes due to drugs, in 65 cases (5.9 %) the medication had to be stopped, and 20 customers (1.8 %) reported that they had been admitted to hospital due to DILI. Compared to individuals without adverse hepatic drug reactions (n = 957), the 141 persons with potential DILI presented more often the following risk factors in multivariate analysis: chronic liver disease (14.4 % vs. 2.4 %, odds ratio [OR] 4.2, 95 % confidence interval [CI] 2.0 - 9.0), chronic renal insufficiency (20.0 vs. 6.8 %, OR 2.2, 95 % CI 1.3 - 3.7), diabetes (34 vs. 15.3 %, OR 2.0, 95 % CI 1.3 - 3.2), family history of chronic liver disease (19.9 vs. 7.7 %, OR 2.1, 95 % CI 1.2 - 3.6), and continuous drug intake for more than 5 years (80.9 vs. 59.3 %, OR 2.1, 95 % CI 1.3 - 3.5). CONCLUSION: These studies show an unexpected high prevalence of DILI in pharmacy customers and identify multiple potential risk factors.

[Current seroprevalence, vaccination and predictive value of liver enzymes for hepatitis B among refugees in Germany]. / Aktuelle Seroprävalenz, Impfstatus und prädiktiver Wert der Leberenzyme für Hepatitis B bei Flüchtlingen in Deutschland.

BACKGROUND: Currently only vague estimates exist for the seroprevalence and vaccination status for viral hepatitis B (HBV) in refugees arriving in Germany during the current refugee crisis. OBJECTIVES: To assess the prevalence of hepatitis B in refugees arriving in northern Germany in 2015. METHODS: In a cross-sectional study in 793 patients from all age groups tests for serological markers of hepatitis B virus infection (HBsAg, anti-HBc) and liver enzymes (ALT, AST, bilirubin, γGT, alkaline phosphatase) were performed in August 2015 at six reception centers in northern Germany. In 258 patients anti-HBs antibodies were assessed additionally. RESULTS: Of the tested refugees, 76.7 % were male, the median age was 28.8 ± 11.4 years, and 7.8 % were children under the age of 18. The overall prevalence of HBsAg and total anti-HBc was 2.3 % and 14.0 % respectively (2.5 % and 14.5 % in men; 1.2 % and 13.5 % in women). Prevalence was highest in 35 to 49-year-old patients for HBsAg (3.1 %) and for refugees over 50 years for anti-HBc (38 %). No immunity to Hepatitis B was found in 62 %, 18.6 % had been vaccinated against Hepatitis B, while 50 % of children aged up to 15 years (n = 12) had been vaccinated. Positive predictive values of elevated AST and ALT for detection of HBsAg was 0 and 0.016, respectively. Only two patients with a positive HBsAg had elevated transaminases. CONCLUSIONS: This study showed a high prevalence of HBsAg in a German refugee sample in comparison to the general German population. Liver enzymes are not an appropriate tool for screening for hepatitis B virus infection.

The Application of Six Sigma Techniques in the Evaluation of Enzyme Measurement Procedures in China.

BACKGROUND: Recently, Six Sigma techniques have been adopted by clinical laboratories to evaluate laboratory performance. Measurement procedures in laboratories can be categorized as "excellent", "good", and "improvement needed" based on sigma (σ) metrics of σ ≥ 6, 3 ≤ σ < 6, and σ < 3, respectively. The quality goal index (QGI) was further investigated for measurement procedures with σ ≤ 3. Improvements of the procedures were recommended based on QGI: QGI < 0.8 indicates that the precision of the procedure needs to be improved; QGI > 1.2 indicates that the trueness of the procedure needs to be improved; 0.8 ≤ QGI ≤ 1.2 indicates that both the precision and trueness of the procedure need to be improved. METHODS: Fresh frozen sera containing seven enzymes (ALT, ALP, AMY, AST, CK, GGT, and LDH) were sent to 78 clinical laboratories in China. The biases for measurement procedures in each laboratory (Bias) were calculated based on the target values assigned by 18 laboratories performing IFCC (International Federation of Clinical Chemistry and Laboratory medicine) recommended reference methods. The imprecision of each measurement procedure was represented by coefficient variations (CV) calculated based on internal quality control (IQC) data. The σ and QGI values were calculated as follows: σ = (TEa-Bias)/CV; QGI = Bias/(1.5 x CV). TEa is allowable total error for each enzyme derived from biological variation. RESULTS: Our study indicated that 7.9% (6/76, ALP) to 31.0% (18/58, AMY) of the participating laboratories were scored as "excellent" (σ ≥ 6), 21.1% (16/76, ALP) to 41.3% (31/75, CK) of the laboratories were scored as "good" (3 ≤ σ < 6), and 31.0% (18/58, AMY) to 71.1% (54/76, ALP) of the laboratories need to improve their enzyme measurement procedures (σ < 3). For those with σ < 3, QGIs were further calculated. Based on QGI values, 8.6% (5/58, AMY) to 35.9% (28/78, LDH) of the laboratories (QGI < 0.8) need to improve the precision of the procedures, 8.0% (6/75, CK) to 52.6% (40/76, ALP) of the laboratories (QGI ≤ 1.2) need to improve the trueness of the procedures; and 2.7% (2/75, AST) to 16.3% (8/49, GGT) of the laboratories (0.8 ≤ QGI ≤ 1.2) need to improve both the precision and trueness of the procedures. CONCLUSIONS: Even though rapid progress has been made to standardize serum enzyme measurements in China in recent years, our study using Six Sigma techniques still suggested that approximately 31.1% to 71.0% of the laboratories need to improve their enzyme measurement procedures, either in terms of precision, trueness, or both.

Dealing with redundant gamma glutamyl transpeptidase in primary care, when requested along with alkaline phosphatase.

The use of gamma glutamyl transpeptidase (GGT) levels as screening test for liver function is controversial. The GGT main utility is in cases in which alkaline phosphatase (ALP) is elevated. We aimed to investigate the request over time for alanine amino transferase (ALT), ALP and GGT, study the effect of a new demand management (DM) intervention for optimal GGT measurement in primary care. Our descriptive study was conducted from January 2010 to December 2020. The intervention was established in November 2019 and consisted of the laboratory information system would automatically remove GGT, if the test had been ordered simultaneously with ALP and there was no prior pathological result on record. We counted the absolute number of measured ALT, ALP and GGT, and calculated the ratios for each of the three markers related to creatinine, and GGT related to ALT in a monthly basis. The number of measured GGT increased slightly and progressively along the study until October 2019, when a decrease was observed. The ALT and ALP request from primary care also increased slightly along years. However, the GGT/ALT ratio never reached the 0.2 goal. Out of the 57,614 GGT requested in primary care patients, 38,167 (66.2%) were not measured. 7633.4€ were saved in reagent. The DM intervention to reduce the measurement of GGT when requested redundantly with ALP in primary care was successful, and the results have been maintained over time as observed by monitoring the GGT/CREA and GGT/ALT indicator results.

Enzymatic diagnosis of Pompe disease: lessons from 28 years of experience.

Pompe disease is a lysosomal and neuromuscular disorder caused by deficiency of acid alpha-glucosidase (GAA), and causes classic infantile, childhood onset, or adulthood onset phenotypes. The biochemical diagnosis is based on GAA activity assays in dried blood spots, leukocytes, or fibroblasts. Diagnosis can be complicated by the existence of pseudodeficiencies, i.e., GAA variants that lower GAA activity but do not cause Pompe disease. A large-scale comparison between these assays for patient samples, including exceptions and borderline cases, along with clinical diagnoses has not been reported so far. Here we analyzed GAA activity in a total of 1709 diagnostic cases over the past 28 years using a total of 2591 analyses and we confirmed the clinical diagnosis in 174 patients. We compared the following assays: leukocytes using glycogen or 4MUG as substrate, fibroblasts using 4MUG as substrate, and dried blood spots using 4MUG as substrate. In 794 individuals, two or more assays were performed. We found that phenotypes could only be distinguished using fibroblasts with 4MUG as substrate. Pseudodeficiencies caused by the GAA2 allele could be ruled out using 4MUG rather than glycogen as substrate in leukocytes or fibroblasts. The Asian pseudodeficiency could only be ruled out in fibroblasts using 4MUG as substrate. We conclude that fibroblasts using 4MUG as substrate provides the most reliable assay for biochemical diagnosis and can serve to validate results from leukocytes or dried blood spots.

[Application of a continual improvement approach to selecting diagnostic markers for acute pancreatitis in an emergency department]. / Aplicación de un método de mejora continua para la selección de los marcadores diagnóstico de pancreatitis aguda en un servicio de urgencias.

OBJECTIVES: To apply a continual improvement model to develop an algorithm for ordering laboratory tests to diagnose acute pancreatitis in a hospital emergency department. MATERIAL AND METHODS: Quasi-experimental study using the continual improvement model (plan, do, check, adjust cycles) in 2 consecutive phases in emergency patients: amylase and lipase results were used to diagnose acute pancreatitis in the first phase; in the second, only lipase level was first determined; amylase testing was then ordered only if the lipase level fell within a certain range. We collected demographic data, number amylase and lipase tests ordered and the findings, final diagnosis, and the results of a questionnaire to evaluate satisfaction with emergency care. RESULTS: The first phase included 517 patients, of whom 20 had acute pancreatitis. For amylase testing sensitivity was 0.70; specificity, 0.85; positive predictive value (PPV), 17; and negative predictive value (NPV), 0.31. For lipase testing these values were sensitivity, 0.85; specificity, 0.96; PPV, 21, and NPV, 0.16. When both tests were done, sensitivity was 0.85; specificity 0.99; PPV, 85; and NPV, 0.15. The second phase included data for 4815 patients, 118 of whom had acute pancreatitis. The measures of diagnostic yield for the new algorithm were sensitivity, 0.92; specificity, 0.98; PPV, 46; and NPV, 0.08]. CONCLUSION: This study demonstrates a process for developing a protocol to guide laboratory testing in acute pancreatitis in the hospital emergency department. The proposed sequence of testing for pancreatic enzyme levels can be effective for diagnosing acute pancreatitis in patients with abdominal pain.

OBJETIVO: Aplicar un ciclo de mejora continua (CMC) para la determinación de un algoritmo de solicitud de pruebas de laboratorio en el diagnóstico de la pancreatitis aguda (PA) en un servicio urgencias hospitalario (SUH). METODO: Estudio cuasiexperimental que aplicó la metodología CMC en dos fase consecutivas en pacientes atendidos en un SUH: en la primera se usaron la amilasa y lipasa para el diagnóstico de PA, y en la segunda solo la lipasa y solo si esta estaba en un rango determinado, se añadía automáticamente la amilasa. Se recogieron datos demográficos, número y valores de amilasa y lipasa, el diagnóstico final, y se realizó una encuesta de satisfacción a los médicos de urgencias. RESULTADOS: El primer ciclo incluyó 517 pacientes, 20 de ellos con PA. Las características de las pruebas diagnósticas fueron: amilasa [sensibilidad (Se): 0,70; especificidad (Es): 0,85; cociente de probabilidad positivo (CPP): 17 y cociente de probabilidad negativo (CPN): 0,31], lipasa (Se: 0,85; Es: 0,96; CPP: 21 y CPN: 0,16) y la determinación de ambas (Se: 0,85; Es: 0,99; CPP: 85 y CPN: 0,15). En el segundo ciclo se incluyeron 4.815 pacientes, de los cuales 118 sufrieron una PA. El nuevo algoritmo propuesto tuvo una Se: 0,92; Es: 0,98; CPP: 46 y CPN: 0,08. CONCLUSIONES: La elaboración de un protocolo de solicitud de marcadores de laboratorio y la estrategia secuencial de solicitud de enzimas pancreáticas pueden ser efectivas para diagnosticar PA en un SUH.

Creatine kinase-MB elevation after coronary intervention correlates with diffuse atherosclerosis, and low-to-medium level elevation has a benign clinical course: implications for early discharge after coronary intervention.

OBJECTIVES: The study evaluated the incidence and predictors of creatine kinase-MB isoenzyme (CK-MB) elevation after successful coronary intervention using current devices, and assessed the influence on in-hospital course and midterm survival. BACKGROUND: The CK-MB elevation after coronary intervention predominantly using balloon angioplasty correlates with late cardiac events of myocardial infarction (MI) and death. Whether CK-MB elevation after nonballoon devices is associated with an adverse short and midterm prognosis is unknown. METHODS: The incidence and predictors of CK-MB elevation after coronary intervention were prospectively studied in 1,675 consecutive patients and were followed for in-hospital events and survival. RESULTS: CK-MB elevation was detected in 313 patients (18.7%), with 1-3x in 12.8%, 3-5x in 3.5% and >5x normal in 2.4% of patients. Procedural complications or electrocardiogram changes occurred in only 49% of the CK-MB-elevation cases; CK-MB elevation was more common after nonballoon devices (19.5% vs. 11.5% after percutaneous transluminal coronary angioplasty; p < 0.01). Predictors of CK-MB elevation on multivariate analysis were diffuse coronary disease (p = 0.02), systemic atherosclerosis (p = 0.002), stent use (p = 0.04) and absence of beta-blocker therapy (p = 0.001). Adverse in-hospital cardiac events were more frequent in patients with >5x CK-MB elevation, with no significant difference between 1-5x CK-MB elevation versus normal CK-MB group. During a mean follow-up of 13 +/- 3 months, the incidence of death in the CK-MB-elevation group was 1.6% versus 1.3% in the normal CK-MB group (p = NS). CONCLUSIONS: The CK-MB elevation after coronary intervention was observed even in the absence of discernible procedural complications and was more common in patients with diffuse atherosclerosis. In-hospital clinical events requiring prolonged monitoring were higher in >5x CK-MB-elevation patients only. Midterm survival of CK-MB-elevation patients was similar to those with normal CK-MB. Our prospective analysis shows a lack of adverse in-hospital cardiac events and suggests that early discharge of stable 1-5x normal CK-MB-elevation patients after successful coronary intervention is safe.

Myoglobin, creatine-kinase-MB and cardiac troponin-I 60-minute ratios predict infarct-related artery patency after thrombolysis for acute myocardial infarction: results from the Thrombolysis in Myocardial Infarction study (TIMI) 10B.

OBJECTIVES: We examined the diagnostic performance of serum myoglobin, creatine-kinase-MB (CK-MB) and cardiac troponin-I (cTnI) for predicting the infarct-related artery (IRA) patency in patients receiving TNK-tissue plasminogen activator (TNK-tPA) therapy for acute myocardial infarction (AMI) in the Thrombolysis in Myocardial Infarction (TIMI) 10B trial. BACKGROUND: A reliable noninvasive serum marker of IRA patency is desired to permit early identification of patients with a patent IRA after thrombolysis. METHODS: We measured myoglobin, CK-MB and cTnI concentrations in sera obtained just before thrombolysis (T0) and 60 min later (T60) in 442 patients given TNK-tPA and who underwent coronary angiography at 60 min. RESULTS: Angiography at 60 min showed a patent IRA (TIMI flow grade 2, 3) in 344 and occluded IRA (TIMI flow grade 0, 1) in 98 patients. The median serum T60 concentration, the ratio of the T60 and T0 serum concentration (60-min ratio) and the slope of increase over 60 min for each serum marker were significantly higher in patients with patent arteries compared with patients with occluded arteries. The area under the receiver-operating characteristic (ROC) curve for diagnosis of occlusion was 0.71, 0.70 and 0.71 for the 60-min ratio of myoglobin, cTnI and CKMB, respectively. The 60-min ratios of > or =4.0 for myoglobin, > or =3.3 for CK-MB and > or =2.0 for cTnI yielded a probability of patency of 90%, 88% and 87%, respectively. CONCLUSIONS: The diagnostic performance of serum myoglobin, CK-MB and cardiac troponin-I (cTnI) 60-min ratios was similar. The probability of a patent IRA was very high (90%) in patients with 60-min myoglobin ratio > or =4.0, and early invasive interventions to establish IRA patency may not be necessary in this group. Serum marker determinations at baseline and 60-min after thrombolysis may permit rapid triage of patients receiving thrombolytic therapy by ruling out IRA occlusion.

Early assessment of reperfusion therapy using cardiac troponin T.

OBJECTIVES: The purpose of this study was to investigate the utility of cardiac troponin T for early assessment of reperfusion therapy. BACKGROUND: Several biochemical markers are used for early noninvasive detection of reperfusion during intravenous thrombolytic therapy. However, cardiac troponin T, a new myocardial-specific marker, has not been used previously for this purpose. METHODS: We measured troponin T and creatine kinase, MB isoenzyme (CK-MB) levels in 38 patients with acute myocardial infarction whose infarct-related artery was totally occluded before reperfusion therapy. Subjects comprised 14 patients with successful angioplasty (group 1), 12 patients with successful thrombolytic therapy (group 2) and 12 patients with unsuccessful attempted reperfusion (group 3). Blood samples were taken every 15 min, and coronary angiography was performed every 5 to 8 min until 60 min after reperfusion (groups 1 and 2) or after the initiation of treatment (group 3). We calculated the increase in troponin T (delta troponin T) and CK-MB (delta CK-MB) 60 min after treatment was initiated and 60 min after reperfusion in groups 1 and 2. RESULTS: Mean (+/- SD) delta troponin T and delta CK-MB levels were 9.35 +/- 7.83 ng/ml and 125 +/- 83 mU/ml in group 1 and 3.23 +/- 3.08 ng/ml and 130 +/- 137 mU/ml in group 2, respectively, 60 min after treatment and were 10.1 +/- 8.35 ng/ml and 131 +/- 84 mU/ml in group 1 and 6.84 +/- 8.30 ng/ml and 158 +/- 146 mU/ml in group 2, respectively, 60 min after reperfusion. These values were significantly higher than those 60 min after treatment in group 3: 0.16 +/- 0.19 ng/ml and 10 +/- 9 mU/ml, respectively. The predictive accuracy for detecting reperfusion using a threshold value of 0.50 ng/ml of delta troponin T and 25 mU/ml of delta CK-MB was 100% in group 1 and 92% in group 2 60 min after treatment, respectively. There was significant correlation between delta troponin T and delta CK-MB. CONCLUSIONS: Serial measurements of cardiac troponin T as well as of CK-MB are useful for early assessment of reperfusion therapy.

Eliminating unnecessary lactate dehydrogenase testing. A utilization review study and national survey.

BACKGROUND: Consensus recommendations call for the elimination of lactate dehydrogenase (LDH) tests from routine rule out myocardial infarction (ROMI) protocols. METHODS: We conducted a utilization review project in which we evaluated the institutional impact of removing LDH and LDH isoenzyme tests from our hospital diagnostic panel. We then conducted a scripted telephone survey of 100 US hospitals to assess the generalizability of this project. RESULTS: All our cardiology staff members supported this intervention. Lactate dehydrogenase isoenzyme test results did not add clinically useful data for any of 200 consecutive patients discharged with a diagnosis of acute myocardial infarction, and selective use of LDH isoenzyme testing in cases where it was clinically believed to be indicated cut costs 99% during the year after our intervention. Furthermore, our telephone survey demonstrated that 66% of US hospitals polled continue to test for LDH isoenzymes in every patient with possible myocardial infarction. CONCLUSIONS: Our results corroborate prior recommendations for the removal of LDH testing from the routine ROMI protocol. Such an intervention may be accomplished easily, with excellent staff acceptance and considerable savings. Most US hospitals continue to include LDH testing in their ROMI panels despite national guidelines recommending otherwise.

Coronary heart disease surveillance: field application of an epidemiologic algorithm.

This report describes the performance of a surveillance system and computerized algorithm for the assignment of definite or probable hospitalized cardiac events for large epidemiologic studies. The algorithm, developed by the Coordinating Committee for Community Demonstration Studies (CCCDS), evolved from the Gillum criteria, and included selected ICD-9-CM codes including codes 410 through 414 for discharge record screening, plus creatine kinase. For the small percentage of cases in which enzyme analysis was inconclusive (8%), presence of pain and/or Minnesota-coded electrocardiograms were included to define the outcome. All data items were easily obtained from medical records by trained lay record abstractors and required no interpretation. From January 1980 through December 1991, 21,183 medical records were screened for ICD-9-CM codes 410 through 414. Of all 410 to 411 ICD-9-CM codes (n = 9026), 36.9% (n = 3220) were classified as definite cardiac events and 10.6% (n = 1057) as probable events. Of all 412 through 414 codes (n = 9070), only 1.8% (n = 227) were classified as definite cardiac events and 5.4% (n = 716) as probable events. The epidemiologic diagnostic algorithm presented in this article used computerized data to assign diagnoses in a standard, objective manner, and was a lower cost alternative to classification of cardiac events on the basis of clinical review and/or more complex record abstraction approaches.

Serum lactate dehydrogenase (LDH) in Pneumocystis carinii pneumonia, tuberculosis, and bacterial pneumonia.

An increase in serum lactate dehydrogenase (LDH) activity is commonly taken to support the presumptive diagnosis of Pneumocystis carinii pneumonia (PCP), although the LDH level may also be increased in other lung infections and in a variety of extrapulmonary disorders. To assess its diagnostic value in patients with fever, lung infiltrates, and a high prevalence of HIV infection, we compared LDH levels in 42 hospitalized patients with PCP, 71 with disseminated tuberculosis (TB), 40 with pulmonary TB, and 37 with bacterial pneumonia. Peak LDH level was higher (p < 0.05) in patients with PCP (547 +/- 157 U/L) and disseminated TB (569 +/- 338 U/L) than in patients with pulmonary TB (258 +/- 66 U/L) or bacterial pneumonia (331 +/- 139 U/L). However, substantial overlap between groups limited its diagnostic value for individual patients. Expressing LDH as its ratio to simultaneous serum aminotransferases (AST or ALT) did not enhance its discriminatory value. Most patients in each group had abnormalities in other serum enzymes (AST, ALT, alkaline phosphatase, gamma-glutamyltransferase), making an isolated elevation of LDH level uncommon (21% of PCP cases). Serum LDH has a high sensitivity for PCP (100% in this series) but must be interpreted with caution given its lack of specificity.

Assessment of clinical enzyme methodology: a probabilistic approach.

A number of techniques are available to assess the clinical value of enzyme methodologies including regression and discriminant analyses, expert systems, neural networks, and probabilistic. Each has its adherents but the probabilistic approach appears to be the most commonly used technique. This approach uses the fourfold contingency table that categorises subjects by both the presence or absence of the target disease-as defined by a gold standard test- and by a test result being above or below a chosen decision threshold. From this classification can be defined the test's sensitivity and specificity. By altering the decision threshold across the entire range of test values a series of sensitivity:specificity pairs can be tabulated. These may be plotted as 1-specificity (or false positive rate or fraction) versus sensitivity (or true positive rate or fraction) to create a receiver operator characteristic (ROC) curve. ROC curves can provide the accuracy of the test (the area under the curve with associated confidence intervals), the rule-in and rule-out decision thresholds, and the clinical power of the test (likelihood ratio). However, a review of three years' publications in a peer-reviewed journal indicated that much of this essential data is usually absent. It is argued that such publications should include the decision thresholds used, the area under the curve and its standard error, a statistical assessment of the difference between two or more ROC plots, the rule-in and rule-out decision thresholds (indicating if these change with time after the onset of disease), and the relevant likelihood ratios.

Urinary N-acetyl-beta-glucosaminidase in the prediction of preeclampsia.

The urinary excretion of N-acetyl-beta-glucosaminidase (NAG), a lysosomal enzyme of the renal tubular cells was analyzed in 177 women divided into nonpregnant healthy controls (n = 46), normal pregnant women in their third trimester (n = 49), pregnant women with transient hypertension (n = 43), and women with preeclampsia (n = 39). Urinary activity of NAG was increased in normal pregnant women and in patients with transient hypertension in pregnancy compared to nonpregnant healthy controls. In preeclamptic women, this increase was found to be much higher than that corresponding to their gestational age; this fact is due to the tissue ischemia that precedes glomerular endotheliosis, but also tubular lesions caused by arteriolar vasoconstriction may have an important role.

Glycosidase activities in gingival crevicular fluid in subjects with adult periodontitis or gingivitis.

Specific glycosidase activities were determined in samples of gingival crevicular fluid (GCF) collected from eight predetermined sites in two groups, each of 20 adult patients, with either gingivitis or periodontitis. The total activities (as units of enzyme activity per sample) of alpha-L-fucosidase, sialidase, beta-N-acetylglucosaminidase, beta-galactosidase, beta-glucosidase and alpha-glucosidase were significantly greater in the periodontitis group. In contrast, the total beta-mannosidase and hexosaminidase A activities were significantly greater in the gingivitis group, while there was no significant difference in the total alpha-mannosidase activity between the groups. Only the specific activities (as units of enzyme activity per min per microliter of GCF) of beta-mannosidase and hexosaminidase A were significantly different between the groups being greater in the gingivitis group. When used to predict the clinical status of individual periodontal sites, the total enzyme activities had specificity and sensitivity values of 91.9 and 61.3%, respectively. Measurement of glycosidase activities might thus have a role in monitoring the efficacy of periodontal treatment or in predicting future periodontal disease but this will require further investigation.

Quality assurance study of cardiac isoenzyme utilization in a large teaching hospital.

Guidelines for diagnosis of acute myocardial infarction recommend that, if acute myocardial infarction is suspected, creatine kinase (CK)-MB levels should be measured on admission and again at 12 and 24 hours. In light of these recommendations, we conducted a quality assurance study to determine whether utilization of CK-MB tests in our institution, a large, university-affiliated teaching hospital, was consistent with current guidelines. Also, several years ago, we had established a policy of cancelling lactate dehydrogenase isoenzyme orders if the request originated from an unauthorized location, unless it was approved by a laboratory staff. Since this policy led to a greater than 90% reduction in the requests for lactate dehydrogenase isoenzyme testing, an additional objective was to reevaluate this policy. Of 774 patients evaluated with CK-MB tests, 294 (38%) received only a single test. Of these single tests, 277 had normal results (CK-MB < 5%). For the remaining 17 patients, the single CK-MB test findings were abnormal (CK-MB > 5%) without follow-up testing. Only two CK-MB tests were ordered for 187 patients (24%). Three or more CK-MB tests were obtained in 293 cases (38%). When two or more CK-MB tests were ordered, the time interval between the first and second tests was inappropriately short in 70% and long in 24%. The recommended timing for the third CK-MB was followed in only 4% of cases. Review of 32 cancellations of lactate dehydrogenase isoenzyme tests disclosed that lactate dehydrogenase isoenzyme tests were requested when unnecessary in 26 cases. Despite published guidelines for use of CK-MB for acute myocardial infarction, physicians at our institution continue to use these tests inappropriately by ordering only single CK-MB tests or by ordering repetitions of CK-MB tests at excessively short or long intervals.

Plasma leukocyte elastase concentration and coronary artery disease.

It has previously been shown that leukocyte elastase is involved in the pathogenesis of atherosclerosis. Few studies have addressed the relation between leukocyte elastase concentrations and coronary artery disease (CAD). The authors investigated (1) the clinical significance of leukocyte elastase determination in the diagnosis of CAD and (2) the relation between plasma leukocyte elastase concentration and lesion morphology. The study included 185 subjects (140 men, 45 women) who underwent coronary angiography during investigation of chest pain; 135 had coronary stenosis (Group I) and 50 had nonstenotic coronaries (Group II). Among Group I patients, those with simple atheromatous plaques were distinguished from those with complex plaques. Elastase concentrations in Group I were greater than in Group II (57.1 +/- 1.16 micrograms I[-1] vs 27.6 +/- 1.0 microgram, I[-1], P<0.001), and greater in complex plaque patients than in those with simple plaques (64.5 +/- 1.24 micrograms I[-1] vs 45.9 +/- 1.01 micrograms I[-1], P<0.001). Logistic regression analysis showed (1) that elastase concentration, age, and sex had independent value for prediction of CAD and (2) that among Group I patients, the risk of complex plaques was greatest for those with high elastase concentration. These results suggest that plasma leukocyte elastase concentration is a sensitive diagnostic marker of CAD and that high values of elastase may indicate the presence of complex atheromatous plaques.

[The appearance of giant negative T waves in anterior acute myocardial infarct with a Q wave is associated with minor myocardial damage and a minor extension of coronary disease]. / La aparición de ondas T negativas gigantes en un infarto agudo de miocardio anterior con onda Q se asocia a un menor daño miocárdico y una menor extensión de la enfermedad coronaria.

INTRODUCTION AND OBJECTIVE: The early inversion of T waves in patients with acute myocardial infarction has recently been related to a better left ventricular function and a more favourable evolution, contrary to what happens in the unstable angina. On the other hand, the significance of the appearance of deep negative T waves in the early phase of some acute myocardial infarction is not known. The aim of this study is to evaluate its relation with the existing myocardial damage and the underlying coronary artery disease extension in anterior some with Q wave. METHODS: 48 patients with a first anterior Q-wave acute myocardial infarction, thrombolized or not, admitted to hospital with an evolution of less than 24 hours, and with a coronariography performed before discharge were analyzed. Giant negative T waves were defined as those which were 8 mm or more from baseline. RESULTS: 17 of the 48 patients presented giant negative T waves (T-group) and 31 did not (N-group). In the T-group patients, the size of the negative T wave was 11.29 +/- 2.86 mm and the number of precordial leads with negative T waves was 4.35 +/- 1.57. There were no differences between both groups in variables such as sex, coronary risk factors, and other basal characteristics. The T-group patients were younger, had lower peak-CK, CK-MB and LDH levels and presented greater recovery of R waves during the follow-up, the differences being significant with the N-group patients. The left ventricular ejection fraction was higher (56.3 +/- 13.4 vs 42 +/- 12%; p < 0.001) and the number of affected coronary vessels was lower in the T-group (1.12 vs 1.64; p < 0.01); there were no differences in the localization or severity of coronary lesions, nor in the frequency of postinfarction myocardial angina. None of the patients in the T-group were Killip > I, while this situation occurred in 38.7% of the N-group patients. CONCLUSIONS: The appearance of giant negative T waves in the acute or early phase of Q-wave anterior acute myocardial infarction is associated with a smaller infarct size, lower functional deterioration and less extension of the underlying coronary disease.