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PubMed2004

Viability of mycobacteria in formalin-fixed lungs.

It is generally accepted that the risk of contracting tuberculosis is relatively high among medical laboratory workers and pathologists. Nevertheless, there is an assumption that once tissue is fixed in formalin, the risk for transmission and subsequent infection of mycobacteria is greatly reduced, if not altogether eliminated. To test the viability of potentially infectious mycobacteria in formalin-fixed tissue, tissue specimens from autopsy lungs fixed in formalin were cultured for mycobacteria. Of 138 cases with histologic evidence of acid-fast bacilli, 12 grew mycobacteria, including 3 Mycobacterium tuberculosis isolates, suggesting that there is a risk of contracting tuberculosis from tissue that has been fixed in formalin, if aerosolization or accidental inoculation should occur.

Animals↗
PubMed2005

Significance of avidity and immunoblot analysis for rubella IgM-positive serum samples in pregnant women.

A total of 512 IgM-positive serum samples from 449 pregnant women referred by microbiologists and medical laboratories for additional testing and final interpretation were collected over a 3-year period. Employment of an IgM capture enzyme immunoassay (EIA) confirmed only 31% of the initial EIA-IgM-positive samples. In order to discriminate acute rubella virus infections, which are associated with increased risk of fetal infection and embryopathy, from persistent or non-specific IgM, IgG avidity index and the presence of IgG with specificity to rubella virus E2 glycoprotein was determined by Western immunoblot. In only six patients (1.3%), a primary infection with rubella virus was diagnosed on the basis of IgM positivity, low avidity IgG, absence of E2-specific IgG in immunoblot concordant with clinical findings as well as consistent changes in follow-up samples. The serological results were not compatible with rubella re-infection. The infection status in 14 patients (3.1%) remained inconclusive even when both avidity assay and immunoblot were used, while restriction to either test did not allow a conclusive interpretation in 11.6% of patients. The use of both assays is clearly better, and therefore, recommended in IgM-positive samples.

Adult↗
PubMed2005

Functional decline in lower-extremity peripheral arterial disease: associations with comorbidity, gender, and race.

PURPOSE: To identify comorbidities associated with increased rates of functional decline in persons with lower-extremity peripheral arterial disease (PAD). We also determined whether female sex and black race were associated with greater functional decline than male sex and white race, respectively, in PAD. METHODS: Three-hundred ninety-seven men and women with PAD were followed prospectively for a median of 36 months. The presence of comorbid illnesses was determined with medical record review, patient report, medications, laboratory values, and a primary care physician questionnaire. Functional outcomes, measured annually, included the 6-minute walk, usual-paced and fast-paced 4-meter walking speed, and summary performance score. The summary performance score is a composite measure of lower-extremity functioning (score range, 0 to 12; 12 = best). RESULTS: Adjusting for known and potential confounders, PAD patients with pulmonary disease had a significantly greater average annual decline in 6-minute walk performance of -34.02 ft/y (95% confidence interval [CI], -60.42 to -7.63; P = .012), rapid-paced 4-meter walk speed of -0.028 m/s/y (95% CI, -0.054 to -0.001; P = .042), and summary performance score of -0.460/y (95% CI, -0.762 to -0.157; P = .003) compared with those without pulmonary disease. PAD patients with spinal stenosis had a greater average annual decline in 6-minute walk performance of -77.4 ft/y (95% CI, -18.9 to -35.8; P < .001) and usual-paced 4-meter walking velocity of -0.045 m/s/y (95% CI, -0.081 to -0.009; P = .014) compared with participants without spinal stenosis. CONCLUSION: At 3-year follow-up, pulmonary disease and spinal stenosis were each associated with a significant decline in functioning among persons with PAD. In contrast, female sex and black race were not associated with functional decline among persons with PAD.

Aged↗
PubMed2006

The uncertainty of the pendulum method for the determination of the moment of inertia.

The purpose of this study was to quantify the uncertainty of the pendulum method for determining the moment of inertia of an object using various suspension distances. Experimental data were collected on a known geometric solid and partial differential equations were derived to calculate the uncertainty. Repeated measures were used to estimate the errors of the mass, period of oscillation, and distance measurements from the axis to the centre of mass. The results showed that the pendulum method was relatively insensitive to measurement errors of mass but was quite sensitive to errors in the period of oscillation. It was also found that the uncertainty of the pendulum method could be drastically reduced to less than 3% by suspending the object with the axis located at the radius of gyration. Most studies using the pendulum method to determine limb inertial properties have adopted a proximal suspension, including the often cited work by Dempster [Dempster WT. Space requirements for the seated operator. W ADC Technical Report 55-159. Ohio: Aero Medical Laboratory, Wright Air Development Centre, Air Research and Development Council, Wright-Patterson Air Force Base; 1955]. The results suggest that validation of imaging techniques to determine inertial properties should use geometric solids in addition to the pendulum method where the object is suspended at a distance estimated to be the radius of gyration. It is further recommended that the uncertainty be reported whenever it is necessary to use the pendulum method.

Acceleration↗
PubMed2004

[Rapid antigen detection tests for diagnosis of group A streptococcal pharyngitis: comparative evaluation of sensitivity and practicability of 16 in vitro diagnostics medical devices performed in July 2002 by the French health products safety agency (Afssaps) as part of its market control mission].

Within the scope of its health products control mission, the French Health Products Safety Agency (Afssaps) collaborating with two expert's sites, has assessed the 16 tests available on the French market in 2002 for rapid diagnosis of the Streptococcus A tonsillitis. The purpose of this study was to verify the reliability and rapidity of these tests and to give some information to the users about their analytical criteria and practicability characteristics. The analytical study has been performed on a same panel of four reference strains of Streptococcus pyogenes dilutions to determine the limit of detection of all the reagents in the same condition of methodology. The limit of detection has been calculated with the results expressed in colony forming unit by ml (CFU/ml). The practicability study has permitted to analyze the quality of the presentation, the easiness of the final reading and of performing tests. A score has been established for each rapid test. A classification of the analytical sensitivity (limit of detection) and practicability (score) of these 16 devices has been established. The limit of detection of the reagents giving the best results allows the detection of the lowest bacterial concentration of the panel which is 10(5) CFU/ml. Regarding practicability, the results suggest that, the immunochromatographic strip methods have the best score in a view with the use by a non medical laboratory.

Antigens, Bacterial↗
PubMedDate not supplied

Childhood cervical lymphadenopathy.

Cervical lymphadenopathy is a common problem in children. The condition most commonly represents a transient response to a benign local or generalized infection, but occasionally it might herald the presence of a more serious disorder. Acute bilateral cervical lymphadenopathy usually is caused by a viral upper respiratory tract infection or streptococcal pharyngitis. Acute unilateral cervical lymphadenitis is caused by streptococcal or staphylococcal infection in 40% to 80% of cases. The most common causes of subacute or chronic lymphadenitis are cat scratch disease, mycobacterial infection, and toxoplasmosis. Supraclavicular or posterior cervical lymphadenopathy carries a much higher risk for malignancies than does anterior cervical lymphadenopathy. Generalized lymphadenopathy is often caused by a viral infection, and less frequently by malignancies, collagen vascular diseases, and medications. Laboratory tests are not necessary in the majority of children with cervical lymphadenopathy. Most cases of lymphadenopathy are self-limited and require no treatment. The treatment of acute bacterial cervical lymphadenitis without a known primary source should provide adequate coverage for both Staphylococcus aureus and group A beta hemolytic streptococci.

Adolescent↗
PubMed1998

A case series of hospitalized patients with elevated digoxin levels.

PURPOSE: Although there is renewed enthusiasm for the use of digoxin in patients with heart failure, current dosing guidelines are based on a nomogram published in 1974. We studied the incidence of and risk factors for elevated digoxin levels in patients admitted to a community hospital, and compared their dosage regimens to published guidelines. SUBJECTS AND METHODS: We reviewed the charts of all patients who had serum digoxin levels greater than 2.4 ng/mL during a 6-month period. We collected demographic and clinical data, indications for digoxin use, digoxin dosage, concurrent medications, laboratory data, and clinical and electrocardiographic features of digoxin toxicity. RESULTS: Of the 1,433 patients with digoxin assays, 115 (8%) patients had elevated levels. Of the 82 patients with complete records and correctly timed digoxin levels, 59 (72%) had electrocardiographic or clinical features of digoxin toxicity. Patients with serum digoxin levels >2.4 ng/mL were slightly older (78 +/- 8 versus 73 +/- 9 years of age; P = 0.12) and had greater serum creatinine levels (3.1 +/- 7.3 versus 1.4 +/- 0.3 mg/dL; P = 0.01) than those with levels < or =2.4 ng/mL. Forty-seven patients had elevated digoxin levels on admission, including 21 patients admitted for digoxin toxicity. Impaired or worsening renal function contributed to high levels in 37 patients, and a drug interaction was a contributory factor in 10 cases. Twenty (43%) of these patients were taking the recommended maintenance dose based on the scheme employed in the Digitalis Investigation Group study. Thirty-five patients developed high digoxin levels while in hospital. In 26 patients, this followed a loading dose of digoxin for the control of rapid atrial fibrillation. Impaired renal function was implicated in all of these patients. Despite the elevated digoxin level, rate control was achieved in only 11 patients of these patients. CONCLUSIONS: Elevated digoxin levels and clinical toxicity remains a common adverse drug reaction. Elderly patients, particularly those with impaired renal function and low body weights, are at the greatest risk. As published digoxin nomograms often result in toxicity, clinical variables need to be monitored. In patients with congestive heart failure and normal sinus rhythm the potential benefit of digoxin is small; thus, patients should receive a dose that minimizes the risk of toxicity. For patients with new onset atrial fibrillation, other agents may be preferable for rate control.

Age Factors↗
PubMed2004

[Quality control in coprology].

Quality control in medical laboratories was defined in guidelines for good execution of laboratory analyses issued by the French health authorities in 1994. Application of these guidelines is difficult in coprology because the sample is a complex heterogeneous matrix which varies with disease, surgery, food intake, and treatment. In addition, commercial quality control kits are not available for stool biochemical analyses and a national quality control program has not been established. We thus developed our own fecal quality control technique using pooling lyophylized stool samples. Manual or partially automated methods are used in coprology, leading to a long pre-analysis phase which is not always taken into account in quality control. This implies the need for complementary tools to insure the quality of coprology analyses. For example, semi-quantitative microscopic lipid analysis can be used as an internal standard for a given specimen. Quality assurance also involves a post-analytical phase where results obtained for a given specimen are compared with other available data and interpreted in light of the patient's clinical and therapeutic status. This quality assurance strategy enables accurate reliable results useful for long-term patient management.

Animals↗
PubMed1997

Comorbidity measures for stroke outcome research: a preliminary study.

OBJECTIVE: To develop standardized comorbidity measures for use in stroke outcome research. DESIGN: Retrospective review of medical records to analyze comorbidities and to study reliability and validity of the newly developed measures, comorbidity index (CI), and weighted comorbidity index (w-CI). SETTING: Tertiary rehabilitation center in Japan. PATIENTS: 106 stroke patients, age 56.5 +/- 13.2 yr, admitted and discharged during the year from May 1994 to December 1995. The median days of duration of stroke, onset to admission, and length of stay (LOS) were 199, 83, and 105.5, respectively. The median admission and discharge Functional Independence Measure (FIM) raw scores were 85 and 110, respectively. MAIN OUTCOME MEASURES: Assessment of interrater reliability with intraclass correlation coefficient (ICC) for total scores and weighted kappa for subscores; assessment of concurrent validity by relating the measures to Charlson's comorbidity index, total numbers of medications, laboratory studies, therapeutic interventions, consultations, and days of interruption (Spearman's rank correlation method); study of predictive validity with discharge FIM score and LOS as dependent variables. RESULTS: The ICCs were .896 for CI and .997 for w-CI, and weighted kappa ranged from .615 to 1.00. CI and w-CI correlated significantly with Charlson index and the above indices of validity. They also correlated negatively with discharge FIM scores and positively with LOS. With stepwise multiple regression analysis, 79.8% of the variance of discharge FIM scores could be explained by w-CI, days from onset to admission, admission FIM score, and deviation in tape bisection task. CONCLUSION: The newly developed comorbidity measures are reliable and valid for use in stroke outcome research.

Activities of Daily Living↗
PubMed1998

Phentolamine effect on the spontaneous electrical activity of active loci in a myofascial trigger spot of rabbit skeletal muscle.

OBJECTIVE: To investigate the effect of phentolamine, a sympathetic blocking agent, on the spontaneous electrical activity (SEA) recorded from a locus of a myofascial trigger spot (MTrS), equivalent to a human trigger point, in rabbit skeletal muscle. DESIGN: Randomized control trial. SETTING: A university medical laboratory. PATIENTS OR OTHER PARTICIPANTS: Nine adult New Zealand rabbits. INTERVENTION: In the experimental group phentolamine mesylate (1mg/kg) was injected into the external iliac artery, followed by flushing with normal saline. The control group was treated with normal saline instead of phentolamine using the same procedure. MAIN OUTCOME MEASURES: SEA was recorded from multiple active loci of MTrSs in the biceps femoris muscle: initially SEA in the same locus was recorded before and immediately after phentolamine (or normal saline) injection; then SEA was recorded from 25 different active loci. The mean of the average integrated signal (AIS) of SEA was analyzed, comparing the effects of phentolamine and normal saline on SEA. RESULTS: In the same active locus, the AIS of SEA showed statistically a linear decay with time after phentolamine injection, with a correlation coefficient of .56 at p < .05. However, no statistical relationship could be derived for the control group data with time by using regression analysis, probably because of large variations among the rabbits and movement artifacts during the experiment. In 25 different loci in the phentolamine group, the mean of the AIS of SEA (7.92 microV) was significantly lower than that of the control group (9.89 microV) at p < .05. CONCLUSIONS: The results support the hypothesis that the autonomic nervous system is involved in the pathogenesis of myofascial trigger points. The application of the AIS as an evaluation index seems to be feasible in the quantitative measurement of SEA.

Adrenergic alpha-Antagonists↗
PubMed2001

Role of inspectors in external review mechanisms: criteria for selection, training and appraisal.

There is a wide consensus that an external review mechanism, both in the form of a peer review, accreditation and certification according to the ISO 9000 series, is more than its standards. The survey process, the role of inspectors and standard interpretation contribute to the essence of the programme itself. Above all, the criteria used for the selection, training and appraisal of inspectors are of paramount importance. While the ISO norms do not require certification bodies to employ "peer reviewers" for the healthcare sector, experience in this sector is the main criterion for recruiting inspectors in accreditation and peer review programmes. However, the ISO/IEC Guide 58, for the setting up and operation of a laboratory accreditation body, specifies that inspectors should have appropriate technical knowledge of the specific calibrations, tests or types of calibration or tests for which accreditation is sought. Training, updating and assessment of inspectors are clearly defined under ISO, but are also systematic under accreditation programmes. Part-time inspectors who are professionals currently practising in a healthcare facility and are in touch with the day-to-day work reality are preferred for accreditation programmes which have self-regulation, education and quality improvement as their main concerns, while full-time and external inspectors are used in external review mechanisms with registration and certification as their main concerns. As well as harmonising the standards for accreditation, it is important to obtain consensus on the criteria to use for the selection, training and assessment of inspectors in order to ensure that different national or international programmes gain mutual recognition.

Accreditation↗
PubMed1998

Laboratory cost control and financial management software.

Economical constraints within the health care system advocate the introduction of tighter control of costs in clinical laboratories. Detailed cost information forms the basis for cost control and financial management. Based on the cost information, proper decisions regarding priorities, procedure choices, personnel policies and investments can be made. This presentation outlines some principles of cost analysis, describes common limitations of cost analysis, and exemplifies use of software to achieve optimized cost control. One commercially available cost analysis software, LabCost, is described in some detail. In addition to provision of cost information, LabCost also serves as a general management tool for resource handling, accounting, inventory management and billing. The application of LabCost in the selection process of a new high throughput analyzer for a large clinical chemistry service is taken as an example for decisions that can be assisted by cost evaluation. It is concluded that laboratory management that wisely utilizes cost analysis to support the decision-making process will undoubtedly have a clear advantage over those laboratories that fail to employ cost considerations to guide their actions.

Cost Control↗
PubMed1998

New directions in laboratory-clinician communications.

The widespread availability of computer-generated data interpretation of clinical laboratory determinations, as well as computerized patterns of disease progression, has given the laboratory professional a powerful tool to enhance the capability of the laboratory to provide consultation for the clinicians. Additionally, the new advances in technology, and the measurement of disease markers on a molecular basis, has added a whole new dimension to Laboratory Medicine. This explosion of technology is affording the clinical laboratory professional a renewed chance to become a more visible and productive member of the team of health providers. There is a need for clinicians to be educated on the capabilities of these tests and their relative powers of diagnosis. The ability to determine vanishingly small quantities of biological molecules also presents the clinical laboratory with the opportunity to provide knowledge for preventative medicine, and for extremely early detection of onset of a disease or changes in its status. Prediction of genetic predisposition, using sophisticated molecular techniques, is another aspect of the novel expertise which the clinical laboratory professional can use to educate the clinical staff, and allow for earlier counseling and treatment. It is with these tools and knowledge that the clinical laboratory can contribute substantially to overall patient care. This role for the clinical laboratory is all the more urgent since the proliferation of information presents a substantial obstacle to the physician for understanding the molecular basis of a large number of disease processes and how this information can be best used to enhance patient care. The Laboratory Medicine professional of today has the unique opportunity to communicate and exchange knowledge and expertise with clinical counterparts, using a variety of educational and electronic means.

Communication↗
PubMed2003

Analytical evaluation of hemoglobin A(1c) dual kit assay on Bio-Rad Variant II: an automated HPLC hemoglobin analyzer for the management of diabetic patients.

OBJECTIVES: To evaluate the analytical performance of the Bio-Rad Variant II HbA(1c) dual kit assay. DESIGN AND METHODS: Precision, carryover, linearity and analytical range were investigated. 139 patients' HbA(1c) results analyzed by the Variant II were compared to the Variant I method. 49 blood samples analyzed by the Variant II at Toronto Medical Laboratories (TML) were compared to the Variant II at Hospital for Sick Children (HSC). RESULTS: Total imprecision was less than 2% for the Variant II assay. The method had a wide analytical range with no carryover. HbA(1c) results were not changed after switching back and forth from the beta thalassemia to HbA(1c) assay. The Variant II showed an average of 0.0027 negative bias compared to the Variant I method. There was an average of 0.0020 negative bias for HbA(1c) results on the Variant II at TML compared to the Variant II at HSC. CONCLUSIONS: HbA(1c) analysis on the Variant II HbA(1c) dual kit is a relatively fast and reproducible method.

Chromatography, High Pressure Liquid↗
PubMed1984

The evaluation of five commercial serum cortisol kits regarding precision and accuracy.

We evaluated Amerlex (Amersham International), Corti-Shure (Nuclear Medical Laboratories), Gammacoat (Clinical Assays), Coat-A-Count and DPC-direct (Diagnostic Products Corporation) radioimmunoassay kits for determination of cortisol in sera. The between- and within-batch precision (coefficient of variation) ranged between 4.4-12.5% and 3.0-10.9% respectively. No one kit exhibited a clearly better precision throughout the assay range. All kits displayed good sensitivity and parallelism. Cortisol concentrations determined by kit methods, in two assayed control sera, were 3-14% higher than by gas chromatography/mass spectrometry. Coat-A-Count and Gammacoat were technically the simplest assays while Corti-Shure and DPC-direct kits had the best designed standard curves over the diagnostic range. The Amerlex kit had the greatest sensitivity, showed least shift in the dose-response curve between assay and was the only assay that came to equilibrium within the specified incubation time.

Evaluation Studies as Topic↗
PubMed2004

Low-molecular-weight heparin does not prevent acute post-ERCP pancreatitis.

BACKGROUND: Studies suggest that heparin has anti-inflammatory effects that could prevent acute post-ERCP pancreatitis. The aim of this investigator-initiated, prospective, randomized, double-blind, multicenter study was to determine whether low-molecular-weight heparin can prevent acute post-ERCP pancreatitis. METHODS: Patients at increased risk for acute post-ERCP pancreatitis based on assessment of known risk factors were randomized to receive low-molecular-weight heparin (Certoparin 3000 IU subcutaneously) or placebo (saline solution 0.3 mL subcutaneously) the day before ERCP. The drug was given 2 hours before and 22 hours after ERCP. Documentation and follow-up included patient history, risk factors for acute post-ERCP pancreatitis, procedure-related data, assessment of pain (visual analogue scale, need for pain medication), laboratory findings before and after ERCP (0, 4, and 24 hours), as well as post-ERCP complications. The two-sided Fisher exact test was used for statistical comparison, and a p value < or =0.05 was considered significant. RESULTS: A total of 458 patients were enrolled in the study. Data from 10 patients could not be evaluated, leaving 221 patients in the low-molecular-weight heparin group and 227 in the placebo group (total 448 patients; 135 men, 313 women; mean age 58 [15] years). Low-molecular-weight heparin and placebo groups were comparable with regard to risk factors for acute post-ERCP pancreatitis (gender distribution, age <65 years, history of pancreatitis, pancreas divisum, disorders of sphincter of Oddi) and procedure-related data (difficult cannulation, diagnostic or therapeutic ERCP, needle-knife papillotomy, endoscopic sphincterotomy, biliary or pancreatic procedure, pancreatic contrast injection, success and final diagnosis of ERCP). Acute post-ERCP pancreatitis occurred in 8.5% (38/448), with one death resulting from severe pancreatitis. Low-molecular-weight heparin offered no benefit compared with placebo based on the frequency of acute post-ERCP pancreatitis (low-molecular-weight heparin, 18/221 vs. placebo, 20/227; p=0.87) and the severity of acute post-ERCP pancreatitis (low-molecular-weight heparin, 14 mild, 3 moderate, one severe; placebo, 18 mild, two moderate, 0 severe). The 24-hour serum amylase values and 24-hour pain scores did not differ significantly between the low-molecular-weight heparin group and the placebo group. Bleeding complications occurred in two patients, both in the low-molecular-weight heparin group (one mild, one moderate). CONCLUSIONS: Prophylactic subcutaneous administration of low-molecular-weight heparin does not prevent acute post-ERCP pancreatitis.

Acute Disease↗
PubMed1975

Semi-automated ECG processing: A simple method to improve efficiency in ECG laboratories.

A method to expedite processing of electrocardiograms (ECGs) is described. The hardware configuration utilizes conventional equipment, and the ECG data is stored in magnetic data cards. The electrocardiographer's interpretation is made using a specially developed code of 253 diagnostic statements of 2 to 9 words each. A minicomputer converts the code into full alpha-numeric description and 2 characters into English statements. The diagnostic print-out appears in the same page as the reproduction of the original ECG data. This system has significantly reduced the ECG processing time, freed manpower to increase availability of technicians and decreased the size of permanent files.

Diagnosis, Computer-Assisted↗