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PubMedDate not supplied

Optimal allocation of testing dollars: the example of HIV counseling, testing, and referral.

BACKGROUND: Health screening programs can be represented as a pathway of sequential processes: offering a test, obtaining consent, conducting the test, providing results, and linking to appropriate care. Using the example of HIV testing, the authors explore the optimal targeting of funds within this pathway. METHODS: The authors develop a microsimulation of HIV testing services and decompose the likelihood that an unidentified HIV-infected person will receive care into the probability of testing [P(test)] and the probability of follow-up [P(follow)] defined as returning for results and linking to care. The authors examine the clinical impact and cost-effectiveness of alternative investments in these component probabilities. RESULTS: At 1% undiagnosed HIV prevalence, cost-effectiveness ratios for HIV testing cluster around $33,000/QALY (quality-adjusted life year) gained. A program with a yield of 0.16 via P(test)=0.20 and P(follow)=0.80 has a cost-effectiveness ratio of $32,900/QALY compared with $36,300/QALY for a program where P(test)=0.80 and P(follow)=0.20. Interventions that improve the probability of success in later stages in the testing pathway [P(follow)] are more cost-effective than investments devoted to earlier stages [P(test)]. CONCLUSIONS: Equivalent pathway outcomes in a screening program do not confer equal value. Limited screening resources are best targeted toward returning for results and linkage among those already identified with disease rather than offering testing to additional people.

AIDS Serodiagnosis↗

PubMedDate not supplied

Drop leg Lachman test. A new test of anterior knee laxity.

We describe a new method of evaluating anterior cruciate stability that we call the drop leg Lachman test. This test is performed with the patient supine and the leg to be examined abducted off the side of the table and flexed 25 degrees. The thigh is stabilized to the examining table with one of the examiner's hands, and the patient's foot is held between the examiner's legs. The examiner's free hand provides the anteriorly directed force as done in the Lachman test. A prospective study of 52 patients who were identified as unilaterally anterior cruciate ligament deficient was conducted. Forty-two subjects were tested while conscious, and 40 subjects were tested under anesthesia. Each subject was examined with a KT-1000 arthrometer. In the conscious group, the drop leg Lachman test resulted in 1.8 mm greater average excursion than the Lachman test. In the anesthetized group, the drop leg Lachman test resulted in 2.4 mm more average translation than the Lachman test. In both groups, the difference between tests was statistically significant. The drop leg Lachman test is physically easier to perform than the Lachman test, and it is a sensitive method of demonstrating anterior laxity in an anterior cruciate ligament-deficient knee.

Adolescent↗

PubMed2004

Teachers' task demands, students' test expectations, and actual test content.

BACKGROUND: Previous studies on instructional importance show that individual students and their teachers differ in the topics that they consider important in the context of an upcoming teacher-made test. AIMS: This study aimed to examine whether such differences between students' test expectations and teachers' intended task demands can be explained by the actual test content. SAMPLES: Participants were history teachers (N=19) and their 11th-grade students (N=388). METHOD: Teachers and students rated the importance of text sections that would be tested in the near future. By means of multilevel analysis, ratings were compared with the occurrence of sections in the tests. RESULTS: Although teachers considered a majority of sections as important and tested only a minority of the sections, their tests still included sections rated as unimportant. The number of such discrepancies, however, was relatively small. Sections the teachers rated important had a much higher probability of being included in the test than sections rated unimportant. For students, a similar but lower degree of correspondence between ratings and test content was found. Interestingly, for sections that teachers considered important, students more often gave a higher rating when these sections appeared in the test than when they did not. The same holds for sections that teachers considered unimportant. CONCLUSIONS: For both teachers and students there is a limited correspondence between perceived task demands and test content. Furthermore, students' perceptions of task demands show a compensation for some of the differences between their teachers' intended task demands and the test demands.

Adolescent↗

PubMed2003

Test-retest reliability of Patrick's hip range of motion test in healthy college-aged men.

This study determined the test-retest reliability of Patrick's test as a hip range of motion assessment method. Fifty healthy college-aged men (mean age = 20.0 years) were studied during 2 testing sessions separated by 24 hours. A single inexperienced tester performed all the measurements in this study. Before data collection, the tester participated in a 15-minute instructional session on how to perform Patrick's test. To determine the range of motion associated with Patrick's test, the tester passively flexed, abducted, and externally rotated the hip of the lower extremity that was to be tested while subjects were in a supine position, so that the lateral malleolus of the tested lower extremity rested just superior to their opposite extended knee. The vertical distance between a mark on the lateral border of the patella of the tested lower extremity and the treatment table was then measured. The results revealed that Patrick's test demonstrated high test-retest reliability (intraclass correlation coefficient = 0.93). The results of this study support the use of Patrick's test as being a reliable measure of general hip motion when used by an inexperienced tester who participated in a 15-minute instructional session on how to perform Patrick's test.

Adult↗

PubMed2006

Confirmatory testing in normokalaemic primary aldosteronism: the value of the saline infusion test and urinary aldosterone metabolites.

OBJECTIVE: Primary aldosteronism has recently been recognized as the most frequent cause of secondary hypertension. Since most patients are normokalaemic, differentiation to essential hypertension is challenging. As differentiation by baseline aldosterone/renin ratio may be insufficient, diagnosis should be confirmed by additional tests. However, as most confirmatory tests have been evaluated in hypokalaemic primary aldosteronism only, we reassessed the value of the saline infusion test and 24 h urinary aldosterone metabolites as confirmatory tests for both normo- and hypokalaemic primary aldosteronism under current antihypertensive medication. PATIENTS AND METHODS: 25 patients with primary aldosteronism (11 hypokalaemic, 14 normokalaemic), 29 patients with essential hypertension and 47 normotensive subjects were studied. The hypertensives received their usual medication with the exception of spironolactone. All subjects underwent a standard saline infusion test (determination of plasma aldosterone before and after 2.0 liters of isotonic saline for 4 hours i.v.) and collected a 24 h urine sample for examination of urinary tetrahydroaldosterone and aldosterone-18-glucuronide. RESULTS: In hypokalaemic primary aldosteronism the saline infusion test showed a reasonable sensitivity (91%) and specificity (90%). However, the test failed to differentiate sufficiently between essential hypertension and normokalaemic primary aldosteronism (sensitivity 57%, specificity 90%). Similarly, urinary tetrahydroaldosterone had higher sensitivity in hypokalaemic than in normokalaemic primary aldosteronism (sensitivity 64% vs 36%, specificity 100%), whereas for aldosterone-18-glucuronide, no differences in hypo- and normokalaemic primary aldosteronism were found (sensitivity 45% and 43%, specificity 100%). CONCLUSIONS: These data show that the saline infusion test as an established test in classical hypokalaemic primary aldosteronism is not a reliable test in the normokalaemic variant of the disease. Due to its low accuracy, determination of urinary aldosterone metabolites did not prove useful in confirming either normo- or hypokalaemic patients. We conclude from our data that these tests should not be used as confirmatory testing in the normokalaemic variant of primary aldosteronism.

Adult↗

PubMed1988

Comparison of the subrenal capsule assay and succinate dehydrogenase inhibition test as drug sensitivity tests for cancer.

The same chemotherapeutic agents were tested against fresh surgical explants of solid tumors obtained from 50 patients using the in vivo subrenal capsule (SRC) assay and the in vitro succinate dehydrogenase inhibition (SDI) test in comparison. Control growth adequate to meet evaluable assay criteria was obtained in 36 of the 50 tumors tested in the SRC assay (72.0%). In the SDI test, 46 of 50 tumors were evaluable (92.0%). Correlations between the two test systems were dependent upon the activity criteria established for each system. With activity criteria set at a change of less than or equal to -2.0 in the drug sensitivity score for the SRC assay and greater than or equal to 50.0% inhibition of succinate dehydrogenase activity for the SDI test, 12.5% of the drugs tested were active in the SRC assay and 22.3% were active in the SDI test. Correlations of tumor response between the two test systems were 31.7% for sensitivity (13/41) and 95.1% for resistance (98/103). In spite of the fundamental difference between the SRC assay and SDI test, meaningful correlations between the test results and clinical tumor responses in both test systems were obtained. This fact suggests that the two methods are complementary to each other.

Animals↗

PubMed1992

Spectrum bias in the evaluation of diagnostic tests: lessons from the rapid dipstick test for urinary tract infection.

OBJECTIVE: To determine if the leukocyte esterase and bacterial nitrite rapid dipstick test for urinary tract infection (UTI) is susceptible to spectrum bias (when a diagnostic test has different sensitivities or specificities in patients with different clinical manifestations of the disease for which the test is intended). DESIGN: Cross-sectional study. PATIENTS: A total of 366 consecutive adult patients in whom clinicians performed urinalysis to diagnose or exclude UTI. SETTING: An urban emergency department and walk-in clinic. MEASUREMENTS: After the patient encounter, but before dipstick test or culture was done, clinicians recorded the signs and symptoms that were the basis for suspecting UTI and for performing a urinalysis and an estimate of the probability of UTI based on the clinical evaluation. For all patients who received urinalysis, dipstick tests and culture were done in the clinical microbiology laboratory by medical technologists blinded to clinical evaluation. Sensitivity for the dipstick was calculated using a positive result in either leukocyte esterase or bacterial nitrite, or both, as the criterion for a positive dipstick, and greater than 10(5) CFU/mL for a positive culture. RESULTS: In the 107 patients with a high (greater than 50%) prior probability of UTI, who had many characteristic UTI symptoms, the sensitivity of the test was excellent (0.92; 95% CI, 0.82 to 0.98). In the 259 patients with a low (less than or equal to 50%) prior probability of UTI, the sensitivity of the test was poor (0.56; CI, 0.03 to 0.79). CONCLUSIONS: The leukocyte esterase and bacterial nitrite dipstick test for UTI is susceptible to spectrum bias, which may be responsible for differences in the test's sensitivity reported in previous studies. As a more general principle, diagnostic tests may have different sensitivities or specificities in different parts of the clinical spectrum of the disease they purport to identify or exclude, but studies evaluating such tests rarely report sensitivity and specificity in subgroups defined by clinical symptoms. When diagnostic tests are evaluated, information about symptoms in the patients recruited for study should be included, and analyses should be done within appropriate clinical subgroups so that clinicians may decide if reported sensitivities and specificities are applicable to their patients.

Adolescent↗

PubMed2003

A comparison of performance outcomes between the Minnesota Rate of Manipulation Test and the Minnesota Manual Dexterity Test.

This study examined the performance outcomes between two tests of manual dexterity, the Minnesota Rate of Manipulation Test [1] and the Minnesota Manual Dexterity Test (1981). Even though the tests are constructed differently and are different versions of the Complete Minnesota Dexterity tests, both tests utilize the same instruction manual and the same normative data. The researchers measured 233 random participants at a Midwestern international airport and in the student center at a local university in Indiana. Each participant completed three trials of a subtest on both versions of the test. One sample t-tests on difference scores indicated statistically significant differences on outcomes of both subtest comparisons as well as overall test score differences (p < 0.000). These significantly different outcomes on the two tests illustrate the need to establish separate normative data on the latest version of the test, the Minnesota Manual Dexterity Test.

Adolescent↗

PubMed2006

[Combining high-risk human papillomavirus DNA test and cytological test to detect early cervical dysplasia].

OBJECTIVE: To assess the value of combining high-risk human papillomavirus (HPV) DNA test and cytological test in detection of early cervical dysplasia. METHODS: During January 2003 to June 2004, a total of 5210 women were screened by combining high-risk HPV DNA test (hybrid capture II, HC-II) and cytological test (liquid-based ThinPrep cytology test), and the abnormal cytological or HPV DNA findings were further biopsied under the colposcope. RESULTS: The age of the patients was between 17 to 80, the average was 34 +/- 9. Final pathological diagnosis was HPV infection in 890 cases, cervical intraepithelial neoplasia (CIN) I in 83 cases, CIN II in 73 cases, CIN III in 80 cases, invasive cervical cancer in 54 cases, endometrial cancer in 5 cases, vaginal intraepithelial neoplasia in 1 case and cervical tuberculosis in 1 case. Based on the criteria of histology and pathology, the sensitivity, specificity, positive-predictive value and negative-predictive value of high-risk HPV DNA test for detecting all cases of CIN II, III were 92.22%, 74.71%, 5.19% and 99.84% respectively. In detecting all cases of CIN II, III by cytological test, for atypical squamous cell of undetermined signification (ASCUS), the sensitivity, specificity, positive-predictive value and negative-predictive value were 90.00%, 80.34%, 11.94% and 99.63% respectively; for low-grade squamous intraepithelial lesion (LSIL), the sensitivity, specificity, positive-predictive value and negative-predictive value were 70.13%, 91.58%, 11.11% and 99.51% respectively; for high-grade squamous intraepithelial lesion (HSIL), the sensitivity, specificity, positive-predictive value and negative-predictive value were 48.05%, 98.46%, 31.90% and 99.21% respectively. By the combination of high-risk HPV DNA test and cytological test, the sensitivity, specificity, positive-predictive value and negative-predictive value for detecting all cases of CIN II, III were 98.70%, 73.08%, 5.21% and 100.00% respectively. The infection rate of HPV in cervical cancer was 85.2% (46/54), in CIN III 92.5% (74/80), in CIN II 86.3% (63/73) and in CIN I 45.8% (38/83). CONCLUSIONS: High-risk HPV DNA test has high sensitivity and negative-predictive value. The combination of high-risk HPV DNA test and cytological test increases the sensitivity and negative-predictive value, but it does not increase the specificity. The performance of biopsy under the colposcope can help the diagnosis of cervical dysplasia.

Adolescent↗

PubMed1984

[What should be the length and inner diameter of the testing device for microbiological efficacy testing of formaldehyde gas sterilization methods?].

The series of tests described in a preceding publication (Spicher and Borchers, 1983) has been continued in a modified way. This time, the dependency of the microbiological test results of a formaldehyde gas sterilization procedure on length and inner diameter of the tubes serving as test pieces was examined. The tubes were 1 or 2 m in length with an inner diameter of 1 or 2 mm. The tests were performed with four different preparations of bioindicators. Spores of Bac. stearothermophilus served as test germs. The preparations differed in the type of suspension used for the preparation of the bioindicators: distilled water, diluted blood (10%), undiluted blood, 10% albumin solution. The spore suspensions had been dried on linen thread. During the test procedure, the bioindicators were located near the sealed end of the tube. After completion of the sterilization procedure, the bioindicators were examined for viable germs. In tubes of identical length, the frequency of indicators carrying viable germs was always higher in those of 1 mm than in those of 2 mm inner diameter. In tubes of identical inner diameter, the frequency of indicators carrying viable germs in those of 2 m length was always higher than in those of 1 m length. This regularity was independent of the type of bioindicators used. The bioindicators for the preparation of which a 10% albumin solution had been employed showed the highest resistance. A somewhat lower resistance was found for the bioindicators prepared with undiluted blood. The bioindicators for which the spores had been suspended in diluted blood proved to have the lowest resistance. If the spores had been suspended in distilled water, the resistance of the bioindicators was a little lower than that of those suspended in undiluted blood, but was higher than that of the dried spores with diluted blood. The test results confirm the effectiveness of the method proposed earlier, i.e. to deposit the bioindicators in special test pieces (e.g. tubes or sounds) for the microbiological testing of formaldehyde gas sterilization procedures. These test pieces must be at least as long and as narrow as the longest and narrowest cavity of the object to be sterilized (tubes, catheters). In order to standardize the microbiological testing of formaldehyde gas sterilization procedures and to guarantee a certain minimum efficiency, the bioindicator as well as the test piece and its size (length and inner diameter) should be standardized.(ABSTRACT TRUNCATED AT 400 WORDS)

Culture Media↗

PubMed1995

HIV testing patterns: where, why, and when were persons with AIDS tested for HIV?

OBJECTIVE: To describe the location of, primary reason for, and time between the first positive HIV test and AIDS diagnosis in a sample of persons with newly diagnosed AIDS. DESIGN: Interviews supplementing information routinely collected through AIDS case reporting. SETTING: Eleven US states and cities. PATIENTS: Persons with AIDS (2441) diagnosed between January 1990 and December 1992. MAIN OUTCOME MEASURES: Location of first positive HIV test, primary reason for testing, and time interval between first positive HIV test and AIDS diagnosis. RESULTS: Overall, persons were tested late in their course of HIV infection: 36% were tested for HIV within 2 months and 51% within 1 year of their AIDS diagnosis. Sixty-five per cent were HIV-tested in acute health-care settings: 33% in hospitals, 28% in physicians' offices, and 4% in emergency departments. Testing during hospitalization was most common among injecting drug users (43%) and persons infected through heterosexual contact (50%). Persons primarily sought HIV testing because of illness (58%); other reasons included being in a known risk group (13%) and having had a known HIV-infected sex partner (8%). Testing because of being in a known risk group was least common among persons infected through heterosexual contact (1%). Among persons in these exposure categories, testing differed by race/ethnicity. CONCLUSION: Most persons with AIDS were tested relatively late in their course of HIV infection, in acute health-care settings, and because of illness. Not knowing one's serostatus precludes early medical intervention and may increase transmission.

AIDS Serodiagnosis↗

PubMed2000

Hormonal placental function tests for fetal assessment in high risk pregnancies.

BACKGROUND: Biochemical tests of fetal well-being such as placental hormone levels have not always shown direct benefits for mothers and babies. OBJECTIVES: The objective of this review was to assess the effects of measuring placental hormone levels during high risk pregnancies. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and MEDLINE. We also contacted study authors. SELECTION CRITERIA: Adequately controlled trials comparing availability with no availability of hormone placental tests in high risk pregnancy. DATA COLLECTION AND ANALYSIS: Trial quality was assessed and data were extracted by two reviewers and this was checked by a colleague. Study authors were contacted for additional information. MAIN RESULTS: Two trials involving 3355 women were included. Methodological quality of the trials was acceptable, but results for only 230 out of 2733 women (abnormal hormone levels) were available from one trial. One trial compared oestriol levels reported promptly with levels measured but not reported. The overall perinatal mortality rate was 30.5 per 1000 live births weighing 500 grams or more. No beneficial effects of oestriol measurement on fetal outcome could be identified (odds ratio of perinatal death 0.87, 95% confidence interval 0.35 to 2.18). For abnormal test results only, the reported oestriol group showed a statistically non-significant trend to less perinatal mortality (odds ratio 0.48, 95% confidence interval 0.15 to 1.60). The other trial compared human placental lactogen measurements reported promptly with measurements not reported until after pregnancy. For abnormal test results, the reported group showed significantly less perinatal mortality with four (3.4%) deaths compared to 17 (15%) in the control group (odds ratio 0.25, 95% confidence interval 0.10 to 0.61). Data from normal test results was not available for this trial. REVIEWER'S CONCLUSIONS: The measurement of human placental lactogen levels may be of some value in high risk pregnancies, but there is not enough evidence to evaluate the use of hormone placental tests generally.

Female↗

PubMed1997

Comparison of dobutamine ECG stress test with predischarge exercise test after acute myocardial infarction.

Exercise testing after acute myocardial infarction is commonly used, but in recent years alternative methods have been proposed. Standard exercise testing was compared with dobutamine electrocardiographic (ECG) stress testing in 100 patients after an acute initial myocardial infarction. Dobutamine ECG stress testing was performed in a standard manner at 5 +/- 1 days after the infarction and exercise testing was performed a mean of 10 +/- 2 days following the event. Agreement between both tests was observed in 91 cases (91%), P < .001, Fisher test kappa value, 0.79). The dobutamine test predicted the result of the exercise test with a sensitivity of 100% (95% confidence interval, 87-100) and a specificity of 88% (95% confidence interval 77-93) for a positive predictive value of 75% (95% confidence interval, 62-97) and a negative predictive value of 100% (95% confidence interval, 91-100). Dobutamine ECG stress testing is concluded to be an objective and reliable procedure, which accurately predicts the results of standard exercise testing. It is inexpensive, easy to perform, and although not yet confirmed, could be particularly useful in patients who cannot perform exercise.

Aged↗

PubMed1999

Mold testing by RAST and skin test methods in patients with allergic fungal sinusitis.

RAST tests have traditionally been considered less sensitive than skin tests during investigation of atopy involving molds. This has been attributed to technical problems such as difficulty in binding the mold antigen to the carrier substrate. Ten patients with proven allergic fungal sinusitis were evaluated for sensitivity to 11 important molds by both RAST and dilutional intradermal testing. A predictable correlation between RAST and skin test scores was observed in many, but not all, cases. Most often this disparity was in the form of greater sensitivity indicated by skin testing than by RAST, sometimes differing by as many as 3 classes. The lack of concordance was not confined to testing for the fungi cultured from the sinuses, nor was it more or less pronounced in the case of dematiaceous fungi. The most likely causes for the disparity noted in this series are subtle differences in antigens used in skin test material and for RAST standards. Skin tests allow for evaluation of delayed and late-phase reactions, a measurement not possible by specific IgE testing with RAST. Delayed skin test reactions were not noted in this series of patients. An additional important finding was the sensitivity of patients with allergic fungal sinusitis to virtually every fungal antigen to which they were tested.

Allergens↗

PubMed2001

[Can the Brucellacapt test be substituted for the Coombs test in the diagnosis of human brucellosis?].

BACKGROUND: Throughout this work we have studied the capacity of Brucellacapt test to replace Coombs test in the serological diagnosis of human brucellosis. METHODS: A total of 66 initial sera from patients with diagnostic of brucellosis were studied. The patients were divided in two groups: 42 patients showing a primo-infection (group1), and 24 patients with a previous case of brucellosis (group 2). As a controls, for the group 1 we have used 100 sera from healthy donors, and for group 2, 28 sera from people that have had clinical brucellosis but actually are in good health. All serum samples were tested in either Coombs and Brucellacapt tests. The diagnostic yield was calculated using ROC (receiver-operating characteristic) plots.Moreover, the results obtained in Coombs and Brucellacapt tests with 397 serum samples from 66 patients with brucellosis were compare with a non-parametric method. RESULTS: The sensibility and specificity for group1 were respectively 1 and 0.98 for Coombs and, 1 and 0.95 for Brucellacapt tests. For group 2, the results in Coombs test were 1 and 0.80, and in Brucellacapt test 0.95 and 0.74. In this second group, the area under the ROC plot was 0.950 for Coombs and 0.904 for Brucellacapt tests. Non statistical differences were observed comparing both serological tests using the Wilcoxon method (Z= -0.213; p=0.8). CONCLUSIONS: Brucellacapt and Coombs tests yield similar diagnostic results in the follow-up of serological samples from patients with brucellosis, and its should consider as interchangeables.

Brucellosis↗

PubMed2006

Use of intradermal dilutional testing and skin prick testing: clinical relevance and cost efficiency.

OBJECTIVES/HYPOTHESIS: The objective was to determine the agreement of the positive results from a multiple skin prick test (SPT) device with the ability to determine a definable endpoint through intradermal dilutional testing (IDT) to compare semiquantitatively the degree of positivity of SPT results with quantitative results from IDT and to analyze the cost of immunotherapy based on SPT compared with IDT guided by SPT. STUDY DESIGN: Retrospective review of clinical data (random accrual). METHODS: One hundred thirty-four patients underwent allergy screening using a multiple SPT device. Antigens testing positive by skin prick device were tested using IDT on a separate day. Antigens testing negative by SPT were not evaluated by IDT. Regional allergy testing practice patterns were determined, and a cost analysis using Medicare rates was performed RESULTS: There was good agreement between an antigen testing positive by SPT and the determination of a definable endpoint (93.33%, n = 1,334 antigens). The degree of positivity from the SPT correlated poorly with the final endpoint concentration (r = 0.40, P < .0001). Blended testing techniques were similar in cost when compared with several commonly used allergy testing protocols. CONCLUSIONS: Antigens which show reactivity to a multiple SPT device usually have a treatable endpoint that is independent of the degree of positivity of the SPT result. IDT is an important step in the determination of the strongest starting dose of immunotherapy that may be safely administered. Initiating immunotherapy in this manner may potentially create significant health care savings by shortening the time required for a patient to reach their individual maximally tolerated dose. The use of a relatively large screening panel is cost effective and does not increase the average number of antigens treated by immunotherapy. Blended allergy testing techniques that include IDT in their protocol are comparable in cost with commonly used allergy testing protocols.

Adult↗

PubMed2004

Artificial disruption of skin barrier prior to irritant patch testing does not improve test design.

BACKGROUND: Irritant patch testing is often performed as a 24- or 48-h occlusive patch test with low concentrations of sodium lauryl sulphate (SLS). OBJECTIVES: The aim of this study was to investigate potential ways to shorten this test procedure and obtain precise test results. PATIENTS AND METHODS: Thirty-six healthy volunteers underwent irritant patch testing with different pretreatments (PT) of the test fields. Occlusive test chambers were applied on the upper back with SLS 0.5%, 1%, 2% and 5% in large Finn Chambers(R). The patches were removed after 4 and 24 h, respectively, depending on the concentration used. Test fields were pretreated as follows: PT 0, field without any PT (control); PT 1, prick with lancet; PT 2, prick with test stamp; PT 3, scratch with lancet; PT 4, incision with standardized incision instrument (0.1-0.2 mm depth). Skin reactions were evaluated by transepidermal water loss (TEWL), skin erythema and skin hydration and as well by a visual score (VS) at 4, 24 and 72 h. RESULTS: Our data show an obvious distinction between PT 0-2 and PT 3-4 at all measurement methods. The average TEWL values with PT 3-4 were higher than those with PT 0-2, especially on the 4-h course. This distinction may derive from the shape and size of the skin impairment achieved by PT 3-4, leading to a mechanical barrier disruption. However, SLS may infiltrate directly into deeper skin layers supported by capillarity. Consequently, no or little penetration through the epidermis and interaction with its structures occurs, which is responsible for irritant skin reactions. The SLS dose in the upper skin layers is therefore lower at these PTs. The lower remaining dose of SLS also explains this distinction, especially for the VS. Additionally, there are presumed reactions in deeper layers of the epidermis and dermis at PT 3-4. CONCLUSIONS: In summary, all data suggest a different reaction pattern from the classical irritant response. Therefore, application without any PT seems to be best suited for irritancy skin testing, especially for visual assessment. PTs prior to irritant patch testing have been shown to be unjustifiable.

Adult↗

PubMed2005

Changes in gastric environment with test meals affect the performance of 14C-urea breath test.

BACKGROUND: (14)C-urea breath test (UBT) is considered to be an accurate diagnostic test for the detection of active Helicobacter pylori infection. Various test meals are used in (14)C-UBT to slow down gastric emptying, and to enhance the gastric distribution, in order to increase the time and area of contact between microorganisms and the tracer substrate. The aim of the present paper was to evaluate the effect of gastric environment on the performance of (14)C-UBT using an alkaline and an acidic liquid test meal having gastric emptying retardant effect. METHODS: The comparison of (14)C-UBT was done with liquid test meals (200 mL water) comprising (i) plain drinking water (PDW); (ii) 1.3 g or 3.0 g citric acid (CA); and (iii) 3.0 g trisodium citrate (TSC). Eighteen patients (37 +/- 12 years, range 18-57 years) with complaints of dyspepsia participated in the study. The status of H. pylori was confirmed by histology and rapid urease test. A total of 93 kBq of (14)C-urea (0.5 mL) in a gelatin capsule was orally administered along with liquid test meals to the overnight fasting subjects. Breath samples were collected and radioactivity measured. Results were expressed as (14)CO(2)/mmol exhaled CO(2) as percentage of administered radioactive urea. RESULTS: Higher acidic gastric environment (pH approx. 2.0) with CA was found to increase the exhaled (14)CO(2) level in a dose-dependent manner as compared to PDW and TSC meal (P < 0.05) at all time points. With TSC test meal, the expired (14)CO(2) level decreased in the lower acidic gastric environment (pH approx. 5.3). The peaks of exhaled (14)CO(2) with TSC test meal were observed at the same time points as that with PDW and CA test meals. The (14)C-UBT with TSC was found to be positive in 77% of patients (10/13). CONCLUSION: Better interaction between the microbial urease and (14)C-urea, caused by a test meal that retards gastric emptying and that changes gastric pH, plays an important role in hydrolysis of the administered (14)C-urea by H. pylori urease.

Adolescent↗