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PubMed1999

Appropriateness of physicians' requests of laboratory examinations in primary health care: an over- and under-ulilisation study.

The aim of this work is to study the appropriateness of the laboratory measurement for quantities that may be conditioned by the result of another quantity, estimating the proportions of inappropriate requests due to over- or under-utilisation. We refer to over-utilisation when a quantity was requested and measured when it was not needed, and we refer to under-utilisation when a quantity was not requested and not measured when it was needed. In our centre, the laboratory staff together with the primary health care physicians of the region designed a new laboratory request form. This request form incorporated an agreed requesting protocol for the most common diagnoses in primary health care. Protocols included, according to each case, one or several of 11 pairs of quantities depending on each case. Second quantity in each pair was measured or not, conditional on the result of the first quantity of the pair, the age, the sex and the diagnosis corresponding to the requested protocol. Following recommendations from scientific societies, we decided what should be the results of the first quantity in the pair so to measure the second quantity in the pair. When recommendations were not available, we reviewed the data contained in the laboratory information system, and we established as non-conditioning values, the levels of the first quantities that were associated with the results of second quantities within their reference intervals in 99.95% of cases. The study was done retrospectively using 46091 old laboratory request forms received in our laboratory over two years. Among the 46091 request forms, the first quantities included in the present forms that incorporate agreed requesting protocols were requested 66434 times. The 66434 corresponding second quantities were measured and should not have been measured in 14225 cases (21.4%) and were not measured and should have been measured in 16137 cases (24.3%). Using the request forms according to the conditioning protocols changes the number of quantities by a mean of 0.66 in every request form. This change would have increased the number of quantities measured by 0.04 quantities per form, but would also have improved the appropriate use of the laboratory.

Diagnostic Tests, Routine↗
PubMed2005

Heart rate characteristics and laboratory tests in neonatal sepsis.

OBJECTIVE: The evaluation of an infant for suspected sepsis often includes obtaining blood for laboratory tests. The shortcomings of the current practice are that the infant has to appear clinically ill for the diagnosis to be entertained, and the conventional laboratory tests are invasive. We have found that the clinical diagnosis of neonatal sepsis is preceded by abnormal heart rate characteristics (HRC) of reduced variability and transient decelerations, and we have devised a predictive HRC monitoring strategy based on multivariable logistic regression analysis that was developed at one tertiary care NICU and validated at another. We hypothesized that HRC monitoring, which is continuous and noninvasive, might be an adjunct to conventional laboratory tests in the diagnosis of neonatal sepsis. The objective of this study was to test the hypothesis that HRC monitoring adds information to conventional laboratory tests in diagnosing neonatal sepsis. METHODS: We prospectively collected heart rate data in 678 consecutive infants who stayed >7 days in the University of Virginia NICU from July 1999 to July 2003. We prospectively measured HRC and noted 149 episodes of sepsis with positive blood cultures for which data were available in 137. We obtained all laboratory test results for ratio of immature to total neutrophil count, white blood cell count, glucose, platelet count, HCO3, arterial partial pressure of carbon dioxide, and pH. We tested hypotheses using multivariable logistic regression modeling adjusted for repeated measures. RESULTS: We found that the HRC index, which was available 92% of the time, was highly significantly associated with sepsis (receiver-operating characteristic [ROC] area: 0.73). The ratio of immature to total neutrophil count, white blood cell count (available 4%-8% of the time, usually around the time of suspected sepsis), and blood glucose and pH (available 28% and 38% of the time) were also significantly associated with sepsis (ROC area: 0.75). HRC and laboratory values added independent information to each other, and a predictive model using all significant variables had ROC area of 0.82. CONCLUSIONS: HRC monitoring adds independent information to laboratory tests in the diagnosis of culture-positive neonatal sepsis.

Blood Chemical Analysis↗
PubMed2004

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae).

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.

Animals↗
PubMed2002

Differences in warfarin dosing decisions based on international normalized ratio measurements with two point-of-care testing devices and a reference laboratory measurement.

STUDY OBJECTIVES: To assess the accuracy of warfarin dosing decisions and the degree of numeric bias between two point-of-care devices using a local reference laboratory's international normalized ratio (INR) as the standard measure, and to determine the relationship between dosing decisions and INR values obtained with the point-of-care devices. DESIGN: Prospective study. SETTING: Outpatient anticoagulation clinic. SUBJECTS: Two hundred two patients taking oral warfarin and 10 control subjects. INTERVENTIONS: For the two point-of-care devices, AvoSure and ProTime, the finger-stick method was used to collect capillary blood samples in each subject. At the same visit, one venous blood sample was collected from each subject for the laboratory analysis. MEASUREMENTS AND MAIN RESULTS: Dosing agreement was assessed as the proportion of agreement between each device and the laboratory in terms of maintenance dosage adjustments (increase, decrease, or no change). The level of agreement between each device and the laboratory was evaluated by dosing agreement analysis, bias analysis, and concordance coefficient analysis. In the dosing agreement analysis, 78% of INR values from the AvoSure device would have resulted in the same dosing decision as that with the laboratory INR values compared with 66% from the ProTime device (p < 0.001). The mean bias for the ProTime device (0.5 +/- 0.4 INR units) was significantly higher (p = 0.005) than that for the AvoSure device (0.4 +/- 0.5 INR units). The ProTime device overestimated low INR values to a greater extent than did the AvoSure device. Concordance between the laboratory measurement and each device was similar (rho(c) = 0.82 for ProTime, rho(c) = 0.76 for AvoSure). CONCLUSIONS: Assessing dosing decisions yielded distinct, useful clinical information. The AvoSure device is associated with less systematic bias and a higher degree of clinical agreement with our reference laboratory measurement than those of the ProTime device.

Adult↗
PubMed1997

Outcomes of patients with no laboratory assessment before anesthesia and a surgical procedure.

OBJECTIVE: To estimate the frequency of perioperative morbidities in patients who underwent anesthesia and a surgical procedure with no preoperative laboratory testing. MATERIAL AND METHODS: We conducted an electronic database search of medical records of 56,119 patients who underwent surgical or diagnostic procedures and anesthesia at Mayo Clinic Rochester in 1994 and found 5,120 who had no laboratory tests done within 90 days before the procedure. From this group, we randomly selected 1,044 patients (87 from each month) to document the absence of preoperative tests, the presence of preexisting disease (by organ system), the type of anesthetic agent, and the outcomes and tests intraoperatively and postoperatively. RESULTS: The 1,044 patients ranged in age from 0 to 95 years (median age, 21). No deaths or major perioperative morbidities occurred (0.0%; exact 95% confidence interval, 0.00 to 0.35%). Although 10 patients underwent blood typing and screening for antibodies immediately preoperatively, no blood transfusions were necessary. Intraoperatively, 17 laboratory tests and 1 electrocardiogram were obtained, and 3 results were abnormal. Postoperatively, 42 blood tests and 2 electrocardiographic procedures were performed. Five of the 42 blood tests showed abnormal results (hemoglobin levels in 3, serum sodium in 1, and arterial blood gases in 1). One electrocardiogram showed normal findings, and the other revealed normal results except for premature ventricular contractions. No laboratory test done intraoperatively or postoperatively was found to change surgical or medical management substantially. One patient who had unanticipated blood loss during an outpatient procedure was admitted to the hospital for observation. CONCLUSION: All 1,044 patients, 97% of whom were relatively healthy, with no recent laboratory testing safely underwent anesthesia and an operation. We conclude that patients who have been assessed by history and physical examination and determined to have no preoperative indication for laboratory tests can safely undergo anesthesia and operation with tests obtained only as indicated intraoperatively and post-operatively. Current anesthetic and medical practices rapidly identify perioperative indications for laboratory evaluation as they arise.

Adolescent↗
PubMed1999

Comparison of plasma total homocysteine measurements in 14 laboratories: an international study.

BACKGROUND: Information on interlaboratory variation and especially on methodological differences for plasma total homocysteine is lacking. METHODS: We studied 14 laboratories that used eight different method types: HPLC with electrochemical detection (HPLC-ED); HPLC with fluorescence detection (HPLC-FD) further subdivided by type of reducing/derivatizing agent; gas chromatography/mass spectrometry (GC/MS); enzyme immunoassay (EIA); and fluorescence polarization immunoassay (FPIA). Three of these laboratories used two methods. The laboratories participated in a 2-day analysis of 46 plasma samples, 4 additional plasma samples with added homocystine, and 3 plasma quality-control (QC) pools. Results were analyzed for imprecision, recovery, and methodological differences. RESULTS: The mean among-laboratory and among-run within-laboratory imprecision (CV) was 9.3% and 5.6% for plasma samples, 8.8% and 4.9% for samples with added homocystine, and 7.6% and 4.2% for the QC pools, respectively. Difference plots showed values systematically higher than GC/MS for HPLC-ED, HPLC-FD using sodium borohydride/monobromobimane (however, for only one laboratory), and EIA, and lower values for HPLC-FD using trialkylphosphine/4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. The two HPLC-FD methods using tris(2-carboxyethyl) phosphine/ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F) or tributyl phosphine/SBD-F, and the FPIA method showed no detectable systematic difference from GC/MS. CONCLUSIONS: Among-laboratory variations within one method can exceed among-method variations. Some of the methods tested could be used interchangeably, but there is an urgent need to improve analytical imprecision and to decrease differences among methods.

Chromatography, High Pressure Liquid↗
PubMed2000

Cost savings associated with changes in routine laboratory tests ordered for victims of trauma.

Not all trauma victims evaluated by the trauma service require a full complement of laboratory tests upon admission. This study set out to determine the cost savings and safety of limited laboratory testing of trauma victims. Before 1998, our admission trauma protocol included 11 laboratory tests for all trauma victims. In 1998, we created two categories: Trauma Blue--severe injury likely (Glasgow Coma Score <13; systolic blood pressure <100 mm Hg at any time; significant head, chest, abdominal, or proximal long bone injury; or clinical suspicion of need for operative or intensive care unit management) and Trauma Yellow--severe injury unlikely. The triage decision was made by the team leader or attending physician. Trauma Blue laboratory tests included an arterial blood gas, blood alcohol, type and screen or crossmatch, and urine dipstick. All patients who did not meet Trauma Blue criteria were entered in the Trauma Yellow group. There were only two tests for the Trauma Yellow group, a venous blood gas and blood alcohol. All arterial and venous blood gases measured pH, pO2, pCO2, HCO3, base deficit, hemoglobin, sodium, potassium, and ionized calcium. Other laboratory tests were done if requested by the trauma team leader or attending physician. All trauma admissions for a 3-month period were entered into this prospective study. The admitting trauma surgeon was surveyed after each admission to evaluate any problems in patient care. The test group was compared with a historical control of 100 consecutive patients under the original laboratory trauma protocol. One hundred and forty-eight (148) patients were entered into the study. Average laboratory cost per patient was $29.82 less with the study protocol. No patient care problem was identified. A cost savings of $29.82 per patient or $20,000.00 a year was realized for our institution, with no change in the quality of patient care. Trauma protocols designed to reflect a patient's potential for serious injury can result in a significant cost savings while preserving patient safety.

Clinical Protocols↗
PubMed2002

A temperate reef fish, Tautogolabrus adspersus, (Walbaum) as a potential model species for laboratory studies evaluating reproductive effects of chemical exposure.

In ecotoxicological testing, there are few studies that report on reproductive output (egg production) of marine or estuarine fish. Cunner (Tautogolabrus adspersus) were studied as a potential model species to evaluate the impact of pollutants with estrogenic activity on reproduction in estuarine fish populations. Cunner inhabit marine and estuarine areas where contaminant discharges are likely. Baseline values for cunner gonadosomatic index (GSI), hepatosomatic index (HSI), and plasma vitellogenin (VTG) were determined in a field reference site (April 1999-December 1999). Male and female GSI indicated that cunner spawning is synchronized. Female HSI and VTG increased prior to GSI. From our laboratory observations, cunner are suitable for conducting experiments with reproductive endpoints indicative of both exposure (vitellogenin levels) and effects (egg production). However, cunner are not sexually dimorphic and stripping ripe fish is the only method to distinguish sex. In preparation for laboratory exposure studies with cunner, we designed a laboratory experimental holding system to accommodate cunner's reproductive behavior, a vertical spawning run to the water surface. Cunner were successfully acclimated from overwintering torpor to spawning condition in the laboratory by gradually changing the environmental conditions of fish held at winter conditions (4 degrees C and 9:15-h light:dark photoperiod) to spawning condition (18 degrees C and 15:9-h light:dark photoperiod). Our results show that cunner successfully spawned daily in the laboratory. They produced fertile eggs in our experimental system designed to accommodate cunner's vertical spawning runs, demonstrating that male and female reproductive behavior was synchronized in the laboratory. Our observations indicate that cunner would be a useful model species for evaluating reproductive effects of environmental contaminants in laboratory studies.

Animals↗
PubMed2002

[Postgraduate trainings program in pathology and laboratory medicine at teaching hospitals of Japan].

It is meaningful to propose a postgraduate training program in pathology and laboratory medicine to select the course after graduation and promote recognition of the roles of pathologists(AP) and laboratory physicians(CP). It is desirable that the training program be common to both AP and CP, although this would be difficult in practice. So author proposes a practical training program that should involve making rounds with AP and CP. The desirable period of training is 3 or 4 years. In the program of laboratory medicine for AP, conferences and CPC are essential and other courses are elective. In the selective program, laboratory management is very important because it will be useful when the graduate becomes a laboratory manager. In the pathology program for CP, autopsy and CPC(as a pathologist) are essential. Training in surgical pathology and cytology are desirable to set limits in materials, for example, liver, kidney, bone marrow, and other tissues. Key points of successful training are good relationships chiefs of AP and CP, high level performance and give-and-take in routine work. It is very difficult to study and maintain the knowledge and technique necessary in all fields of pathology and laboratory medicine. So the author emphasizes that the training program should be constructed to focus on useful issues in routine work and management of laboratory.

Curriculum↗
PubMed2002

Effectiveness and residual activity comparison of granular formulations of insect growth regulators pyriproxyfen and s-methoprene against Florida mosquitoes in laboratory and outdoor conditions.

Effectiveness and residual activity tests of granular formulations of 2 insect growth regulators (IGRs), s-methoprene and pyriproxyfen, against laboratory-reared larvae of 5 colonized mosquitoes, Aedes aegypti, Aedes albopictus, Aedes taeniorhynchus, Anopheles quadrimaculatus, and Culex nigripalpus, were conducted in the laboratory and outdoors in plastic tubs. Culex quinquefasciatus was exposed to these two IGRs in the laboratory only. Each IGR formulation was applied at 0.02 and 0.05 ppm active ingredient (Al) against 5 of the 6 mosquito species both in the laboratory and the outdoor evaluations, whereas Cx. quinquefasciatus was exposed to 0.2 and 0.4 ppm AI of s-methoprene, and 0.1 and 0.2 ppm AI of pyriproxyfen in the laboratory. s-Methoprene at 0.02 and 0.05 ppm AI resulted in variable levels (<39-100%) of inhibition of adult emergence in the 5 species monitored for 6 weeks after treatment under both test conditions. Aedes taeniorhynchus was the most susceptible to s-methoprene in terms of initial and residual activity. Culex quinquefasciatus and Ae. albopictus were the most tolerant to s-methopene, with maximum emergence inhibitions amounting to 84% in Cx. quinquefasciatus at 0.4 ppm and 44.3% in Ae. albopictus at 0.05 ppm during the 1st week in the laboratory. Pyriproxyfen at comparable treatment rates to s-methoprene caused very high levels (>80-100% in most cases) of initial and residual emergence inhibitions of the tested species in the laboratory as well as outdoors. In several species, pyriproxyfen induced complete inhibition of adult emergence for several weeks after treatment, even at the lower rate of 0.02 ppm. The World Health Organization has recently recommended the use of pyriproxyfen for the control of some mosquito species at specified rates in certain habitats.

Aedes↗
PubMedDate not supplied

Assessment of performance of laboratories in determining acrylamide in crispbread.

A proficiency testing round was undertaken to assess the performance of laboratories to measure acrylamide in a sample of crispbread. Retail samples of crispbread were ground to a fine powder and after thorough mixing were packed in 40 g units for distribution. Ten samples were selected at random and analyzed in duplicate for acrylamide by liquid chromatography/mass spectrometry (LC/MS). Standard statistical tests showed that the material was homogeneous for the purposes of proficiency testing. Test samples were distributed to 55 laboratories in 16 countries in Europe, North America, Australia, and the Middle East. The results were analyzed by standard proficiency testing statistical procedures, and laboratories were awarded z-scores on the basis of their reported results. Based on a target standard deviation (sigmap value) taken from the Horwitz equation, for a robust mean value of 1.2 mg/kg acrylamide, satisfactory results (z-score within +/- 2 for those between 0.8 and 1.6 mg/kg) were obtained by 86% of the 37 laboratories that returned results. Only 1 laboratory was unsatisfactory and 4 had questionable results. About equal numbers of laboratories used gas chromatography (GC)/MS and LC/MS procedures with about 25% using MS/MS and one using GC with electron capture detection. There was no evident trend in performance or bias in results. GC/MS and LC/MS data were evenly distributed across the population of laboratories reporting results.

Acrylamides↗
PubMed2005

Locomotor compensation creates a mismatch between laboratory and field estimates of escape speed in lizards: a cautionary tale for performance-to-fitness studies.

A key assumption in evolutionary studies of locomotor adaptation is that standard laboratory measures of performance accurately reflect what animals do under natural circumstances. One widely examined measure of performance is maximum sprint speed, which is believed to be important for eluding predators, capturing prey, and defending territories. Previous studies linking maximum sprint speed to fitness have focused on laboratory measurements, and we suggest that such analyses may be appropriate for some species and intraspecific classes, but not others. We provide evidence for a general inverse relationship between maximum laboratory sprint speed and the percentage of maximum capacity that animals use when escaping from a threat in the field (the model of locomotor compensation). Further, absolute values of field escape speed and maximum laboratory speed are not significantly related when comparing across a diverse group of Anolis and lacertid lizards. We show that this pattern of locomotor compensation holds both within (i.e., among intraspecific classes) and among lizard species (with some exceptions). We propose a simple method of plotting field escape speed (y-axis) versus maximum laboratory speed (x-axis) among species and/or intraspecific classes that allows researchers to determine whether their study organisms are good candidates for relating laboratory performance to fitness. We suggest that species that reside directly on, or near the "best fitness line" (field escape speed = maximum laboratory speed) are most likely to bear fruit for such studies.

Analysis of Variance↗
PubMed1983

The guided design strategy in the biochemistry laboratory.

This article describes a nontraditional biochemistry laboratory course for first-year dental students. The course consisted of two laboratory exercises adapted to the guided design strategy and a short research project. The major advantage of the guided design laboratories was subjectively determined to be the development of problem-solving skills, which students previously enrolled in a traditional laboratory course seemed to lack. Students exposed to the guided design approach successfully applied these skills when performing their research projects. These students also reflected a better understanding of the biochemical principles encountered. The major disadvantages were the great amount of faculty time required to prepare the guided design materials and the reduced amount of subject matter covered. Student evaluation scores of the new laboratory program showed dramatic improvement over those for the traditional laboratories. In addition, students' attitudes toward the new biochemistry laboratories were more positive than those exhibited in the traditional course.

Biochemistry↗
PubMed1983

The clandestine drug laboratory situation in the United States.

Clandestine, or illegal, laboratories are operated by the criminal element to circumvent legal requirements with the goal of supplying drugs of abuse to the illicit market. Investigation of clandestine drug manufacturing laboratories is a high priority of the U.S. Drug Enforcement Administration (DEA) because elimination of these laboratories will prevent drugs of abuse from reaching the illicit drug traffic. One of the important responsibilities of forensic chemists assisting in investigations of clandestine drug laboratories is to be familiar with the methods of synthesis being used by clandestine laboratory operators. A review of clandestine laboratory seizures during the period of 1978 through 1981 will be provided to familiarize forensic chemists with current information on the types of laboratories being seized in the United States and the methods of synthesis being used.

3,4-Methylenedioxyamphetamine↗
PubMed1995

Using characteristic changes in laboratory values to assist in the diagnosis of hemorrhagic shock and encephalopathy syndrome.

OBJECTIVES: (1) To determine whether the laboratory abnormalities in hemorrhagic shock encephalopathy syndrome (HSES) follow a characteristic pattern of evolution; and (2) to describe the clinical characteristics and outcome of this group of children. DESIGN: Retrospective review of hospital records. SETTING: Pediatric intensive care unit in an academic children's hospital. PATIENTS: Seventeen children who received the diagnosis of HSES. MEASUREMENTS: (1) To support the diagnosis of HSES, the following laboratory tests were obtained: creatine phosphokinase, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, creatinine, anemia, thrombocytopenia, coagulation abnormalities, and a metabolic acidosis; and (2) patient characteristics at the time of admission and during the illness and patient outcome were recorded. RESULTS: The median time for laboratory abnormalities in HSES to reach the most aberrant levels was 1.2 to 1.4 days. After reaching maximal deviation, the laboratory values gradually returned to normal. The severity of laboratory abnormalities was not predictive of mortality. All patients were comatose, had seizures, and required fluid resuscitation. Respiratory failure occurred in 12 (71%) of 17 patients. Vasopressor infusions were used for 8 (47%). Viral cultures were performed in 15 patients and were positive in 8 (53%). Eleven (64%) patients survived. CONCLUSIONS: The laboratory abnormalities that are characteristic of HSES follow a distinctive pattern of evolution during the course of the illness. Although the sensitivity, specificity, and predictive value of this pattern of laboratory abnormalities are not known, it might provide a useful tool in diagnosing HSES and excluding other illnesses. Viral illness is common in HSES. The severity of illness and mortality in this group of patients is similar to other descriptions of HSES.

Brain Diseases↗
PubMedDate not supplied

Performance of two immunochemical assays in the analysis of peanuts for aflatoxin at 37 field laboratories.

A study was conducted to measure the precision of 2 rapid aflatoxin assay systems in use at 37 peanut buying points during the 1991 harvest season. Aflatoxin laboratories were established at the 37 buying points to analyze peanut samples from all incoming farmers' stock loads as part of a joint project sponsored by various segments of the U.S. peanut industry and the U.S. Department of Agriculture. Eighteen laboratories were equipped with Neogen's veratox FSP rapid assay system, whereas 19 laboratories used Vicam's Aflatest rapid assay system. To monitor the performance of the field laboratories during the project, 3 portions of each of six 27 kg samples of ground peanuts were sent to each laboratory for analysis over a period of 6 weeks. Aflatoxin concentrations ranged from 0 to 300 ng/g when eight 200 g subsamples of each sample were analyzed by liquid chromatography (LC). For the 5 samples contaminated with aflatoxin, relative standard deviations for repeatability (RSDr) for laboratories using veratox FSP ranged from 18.66 to 53.29%, and the relative standard deviations for reproducibility (RSDR) ranged from 22.79 to 59.29%. For laboratories using the Aflatest system, RSDr values ranged from 18.70 to 41.48%, and RSDR values ranged from 23.84 to 47.56%. Horwitz ratios < 2.0 were found for 4 of the 5 contaminated samples for both methods, indicating that the overall precision of the 2 methods used in the project was good. Mean aflatoxin concentrations, as determined with the rapid assay systems, were generally lower than those determined by LC, particularly for more highly contaminated samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗
PubMed1993

Utility of routine laboratory testing for detecting intra-abdominal injury in the pediatric trauma patient.

OBJECTIVE: To assess the prevalence of laboratory abnormalities (complete blood cell count, electrolytes, blood urea nitrogen, creatinine, glucose, aspartate aminotransferase, alanine aminotransferase, amylase, lipase, urinalysis [U/A]) and the sensitivity and specificity of the physical examination (PE) and screening laboratory tests for identifying intra-abdominal injury (IAI) in moderately injured pediatric patients. DESIGN, PARTICIPANTS, AND SETTING: Phase I: Retrospective chart review of 285 consecutive level II (moderately injured) trauma patients seen at a children's hospital emergency department/pediatric trauma center. All patients were received directly from the scene and had the following data recorded: mechanism of injury, Glasgow coma score, trauma score, pediatric trauma score, systematically recorded PE findings, laboratory results, and injuries detected during hospitalization. Phase II: To confirm the sensitivity of the PE and U/A found in phase I, the model was applied to 91 additional trauma patients identified by International Classification of Diseases, 9th revision (ICD-9) codes as having IAI. INTERVENTION: None. RESULTS: Phase I: A total of 3939 tests were ordered for the 285 patients entered in phase I. Aspartate aminotransferase and alanine aminotransferase values were obtained in 59% of patients; glucose level was obtained in 78% of patients; complete blood cell count, U/A, and levels of electrolytes, blood urea nitrogen, creatinine, amylase, and lipase were obtained in more than 85% of patients. The overall prevalence of laboratory abnormalities was 5.7%. Fourteen patients (4.8%) were identified who had a total of 23 significant IAIs (9 pancreatic, 6 splenic, 5 renal, 3 hepatic). The PE combined with U/A showing more than five red blood cells per high-power field had a sensitivity of 100%, specificity of 64%, positive predictive value of 13%, and negative predictive value of 100% for the detection of IAI. The presence of laboratory abnormalities suggesting injury did not increase the sensitivity of the model and significantly decreased both specificity and positive predictive value. Phase II: The PE combined with U/A identified an abnormality in 89 (97.8%) of 91 cases (95% confidence interval = 94.8% to 100%). CONCLUSIONS: In the moderately injured pediatric trauma patient, (1) there is a low prevalence of laboratory abnormalities; (2) the PE combined with U/A is a highly sensitive screen for IAI; and (3) in patients with a normal PE of the abdomen and a normal U/A, laboratory testing seldom identifies unsuspected IAI.

Abdominal Injuries↗
PubMed1995

INR reporting in Canadian medical laboratories. Thrombosis Interest Group of Canada.

A written survey of all licensed medical laboratories in Canada performing coagulation testing was performed to investigate the level of knowledge and overall usage of the INR system for reporting prothrombin time results in medical laboratories. There was an overall response rate of 857 of 1,228 laboratories surveyed. Fifty-seven percent of responding laboratories utilized some format of INR reporting. The ISI of the individual thromboplastin utilized was known by 89% of laboratories. The ISI of the thromboplastin utilized was known to be specific for the particular reagent/instrument combination in 44% of cases. Fifty-five percent of client physicians preferred PT results to be reported in seconds while 42% desired an INR format. The situation in Canada is similar to the United States in that further education regarding the INR system for PT reporting is required by both medical laboratories and physicians.

Administration, Oral↗