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At least 19 recordsLinked to original sources

PubMed1989

Guidelines for evaluation of reagent strips. Exemplified by analysis of urine albumin and glucose concentration using visually read reagent strips. International Federation of Clinical Chemistry, Scientific Division.

Reagent strips are frequently used in the practice of laboratory medicine as well as outside the professional laboratories. In the present report, a scheme is presented which allows a reproducible description of the performance of reagent strips. This is exemplified using strips intended for estimation of urinary albumin and glucose. Experimental conditions that are particularly important for these components are given. Suitable and necessary items which should be included in the protocol presenting results of an evaluation are listed. The guidelines might have general applicability in evaluation and description of tests with a limited number of possible results.

Albuminuria↗

PubMed1992

Characteristics of a new urine, serum, and saliva alcohol reagent strip.

We have tested an ethanol reagent strip developed at the Addiction Research Foundation of Ontario. Alcohol dehydrogenase and nicotinamide adenine dinucleotide, in the presence of pyrazole, react with ethanol to yield acetaldehyde plus reduced nicotinamide adenine dinucleotide. The latter reduces iodonitrotetrazolium chloride in the presence of diaphorase, generating an intense red color. The rate of color development is proportional to the concentration of ethanol. Color is compared at a specific time against a calibrated color scale ranging from green (negative) to red, representing alcohol concentrations of 0, 25, 50, 100, 200, and 400 mg/dl (0-0.4%; 0-87 mmol/liter). We were able to interpolate the color observed between the calibrated blocks. When tested on urine, serum/plasma, and saliva, ethanol concentration determined by the reagent strip correlates well with ethanol concentration as determined by gas chromatography or by automated enzymatic analysis (r = 0.92-0.98, p less than 0.001; slope 0.83-1.16). The reagent strip was shown to be used appropriately by nonexperienced individuals following a 1-min explanation (reagent strip values, r = 0.92; p less than 0.001, slope = 0.97, versus gas chromatography). The reagent strip does not react with methanol (wood alcohol), isopropanol (rubbing alcohol), and ethylene glycol (antifreeze) often found in accidental poisonings. In 379 clinical samples obtained without exclusion criteria from 12 hospital emergency rooms and a liver clinic, the sensitivity of the reagent strip in detecting ethanol was 98%. Specificity was 99%. The reagent strip was found to have virtually unlimited stability under refrigeration (4 degrees C) and to be stable for 3 to 4 months at room temperature (22-23 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗

PubMed1976

Clinical evaluation of commercial reagent strips for detection of significant bacteriuria in dogs and cats.

The reagent strip technique of quantitative urine culture was a satisfactory screening test for the detection of significant bacteriuria in dogs and cats. The reagent strip technique was found to be of almost equal sensitivity as the calibrated loop technique in identifying significant bacteriuria. Significant bacteriuria was detected in 38 of 148 urine samples evaluated by the calibrated loop technique. Of these 38 urine samples, significant bacteriuria was detected in 35 by the commercial test. False-negative results were obtained with reagent strips in 1 urine sample which had significant bacteriuria by the calibrated loop technique. The other 2 samples had bacterial counts of suspicious significance (10,000/ml of urine) by the reagent strip technique. False-positive results were obtained with the reagent strip technique in 3 urine samples; however, all 3 urine samples had bacterial counts (10,000/ml of urine) of suspicious significance when evaluated by the calibrated loop technique. The reagent strip technique was not satisfactory for the examination of patients with gross hematuria. The nitrite test portion of the commercial test did not detect significant bacteriuria in all samples and, therefore, was not suitable as a screening test for significant bacteriuria in dogs and cats. The nitrite test may have been inhibited by ascorbic acid, a metabolite which normally may exist in the urine of these animals.

Animals↗

PubMed1990

Evaluation of the reagent strip test for haematuria in the control of Schistosoma haematobium infection in schoolchildren.

Several recent reports have indicated the potential of the reagent strip test for haematuria in the diagnosis of Schistosoma haematobium infection. Approximately 15,000 schoolchildren from a population of 40,000 people were examined for reagent strip microhaematuria on three occasions between 1986 and 1987 and treated with praziquantel 40 mg/kg if positive. The reagent strip was evaluated against a single filtration of 10 ml urine for S. haematobium eggs. Initially 65.9% of children were treated followed by 37.5% at the second examination 6 months later and 44.5% at the third examination a further 12 months later. Reagent strip sensitivity was shown to be related to the intensity of infection. The reagent strip specificity improved significantly with successive treatments indicating that haematuria was more sensitive than parasitology for light infections. The amount of S. haematobium reinfection was highest in the 7-9 year olds decreasing to the 16-20 year age group which suggested an impact of protective immunity. It was concluded that microhaematuria is a valuable indicator for the diagnosis of S. haematobium in national control programmes and can be substituted for parasitological examination with advantage but sensitivity and specificity should continue to be evaluated throughout the programme.

Adolescent↗

PubMed1991

Semiquantitative determination of serum IgE by reagent strips: PRIST/TOTALE correlation.

Due to its great simplicity, the determination of total and specific IgE with a reagent strip could be a screening method for in vitro allergy diagnosis if a correlation with classical techniques is verified. The TOTALE reagent strip for semiquantitative determination of total serum IgE is one of these methods and unites the now classical foundation (anti-IgE/IgE/anti-IgE labeled sandwich) and the ease of the reagent strip technique. In a preliminary evaluation of these methods we compared the PRIST isotopic method to the TOTALE one for serum total IgE. In summary, the most relevant consequences from this comparison are the following ones: a) The initial sample is the same for both: serum. b) No additional equipment or materials other than the serum sample are needed for TOTALE practising. c) The reagent strip has a lower cost and is faster than the PRIST method. d) Correlation coefficients were 0.89 (n = 35) in the range of measurement under study and 0.93 (n = 23) in the range from 5 to 200 U/L.

Child↗

PubMed1990

[Evaluation of the detection of urinary tract infection by the reagent strip method in hospitalized patients].

Asymptomatic urinary tract infections (UTI) are frequent in hospital patients. Two prospective studies were carried out to evaluate the reagent strip method used to detect these infections. The diagnosis of UTI rested on cytobacteriological examination of urine. Detection by reagent strip was performed either in the microbiology laboratory (study 1: 976 samples) or at the patient's bedside and in the laboratory (Study 2: 225 samples). The strips were examined visually and by an automated device. There was no significant difference between the results obtained with these two reading methods. Study 1 showed that the reagent strip is more useful to exclude the diagnosis of UTI by using the leucocyte zone alone or combined with the nitrite zone (negative predictive value 98 percent) than to assert this diagnosis. Study 2 showed that the nitrite zone was less sensitive when it was examined at the laboratory than at the patient's bedside. Analysis of discordances between reagent strip and cytobacteriology in the light of data supplied by the patient's medical records made it possible to improve the negative predictive value of the tests. (100 percent). Thus, 60 percent of cytobacteriological examinations could be avoided if this type of examination was performed only in urine with positive leucocyte and nitrite zones. This means a 15 percent saving in B-coded examinations performed in hospital microbiology laboratories.

France↗

PubMed1990

[Evaluation of the reagent strip method to detect urinary tract infections. In hospital patients].

Asymptomatic urinary tract infections (UTI) are frequent in hospital patients. Two prospective studies were carried out to evaluate the reagent strip method used to detect these infections. The diagnosis of UTI rested on cytobacteriological examination of urine. Detection by reagent strip was performed either in the microbiology laboratory (study 1:976 samples) or at the patient's bedside and in the laboratory (Study 2:312 samples). The strips were examined visually and by an automated device. There was no significant difference between the results obtained with these two reading methods. Study 1 showed that the reagent strip is more useful to exclude the diagnosis of UTI by using the leucocyte zone alone or combined with the nitrite zone (negative predictive value 98 percent) than to assert this diagnosis. Study 2 showed that the nitrite zone was less sensitive when it was examined at the laboratory than at the patient's bedside. Analysis of discordances between reagent strip and cytobacteriology in the light of data supplied by the patient's medical records made it possible to improve the negative predictive value of the tests. (100 percent). Thus, 60 percent of cytobacteriological examinations might be avoided if this type of examination was performed only in urine with positive leucocyte or nitrite zones. This means a 15 percent saving in B-coded examinations performed in hospital microbiology laboratories.

Hospitals↗

PubMed1991

The usefulness of urinalysis reagent strips in selecting Schistosoma haematobium egg positives before and after treatment with praziquantel.

The effectiveness of urinalysis reagent strips for haematuria and proteinuria in selecting Schistosoma haematobium egg-positive persons was studied on 426 subjects of all ages in a Kenyan community before and 3 months after treatment with praziquantel. Before and after treatment, the degree of urinary blood or protein and prevalence of egg positives were closely associated. Haematuria and proteinuria were positively correlated with urinary egg counts. For selecting egg-positive persons with reagent strips, a combined criterion 'haematuria trace up or proteinuria 1 + up' was considered the best in this area. With this criterion, sensitivity and specificity before treatment were 69.6 and 84.4 respectively. These values remained at the same level (70.7 and 81.2%) even after treatment with praziquantel reduced prevalence from 59.4 to 13.6% (77% reduction) and intensity of infection from 57.2 to 11.3 eggs 10 ml-1 of urine (80% reduction). Although the sensitivity was not very high, heavy infections were not missed. If all those selected with reagent strips were treated and cured, a 98% reduction in total egg excretion by the community would be expected in both our first and second urine examinations.

Adolescent↗

PubMed1992

Screening for bacteriuria in urological patients using reagent strips.

A rapid and accurate ward-based method of diagnosing urinary infection would be of value in determining the prescription of antibiotics in pre-operative urological patients. This study describes the sensitivity and specificity of a screening technique based on commercially available reagent strips in the diagnosis of urinary infection. A total of 222 pre-operative samples and 83 post-operative samples was studied to compare the results of formal urine culture and reagent strips. Using a definition of a positive nitrite or a positive leucocyte esterase on the reagent strips as being suggestive of infection, it was found that the strips had a sensitivity of 91% and a specificity of 85% compared with formal culture in pre-operative samples. The results from post-operative samples were less satisfactory, the strips having a sensitivity of only 71% and specificity of 55%. The strips were insensitive but specific in the identification of pyuria in pre-operative specimens. These results suggest that reagent strips can be used as a ward-based method to identify men at risk of infection before urological procedures, and may allow selectivity in the use of peri-operative antibiotics.

Adolescent↗

PubMedDate not supplied

The effect of haematocrit on reagent strip tests for glucose.

Four blood glucose reagent strips (BM-Test 1-44, Glucostix, Hypoguard GA, and Exactech), used in conjunction with measuring devices produced by the same manufacturer, were investigated with respect to the influence of haematocrit. The erythrocytes and plasma of fresh blood samples were separated, then remixed in different proportions to achieve a range of haematocrit values and the resulting specimens subjected to glucose assay. All the strip tests showed some influence of haematocrit, low haematocrits producing higher glucose results and vice versa, but some were much more affected than others. The Hypoguard GA was most affected and the BM-Test 1-44 least. In the worst case, glucose results differed by 49% from one end of the normal adult haematocrit range to the other.

Adult↗

PubMed1991

Accuracy of reagent strip testing for urinary tract infection in the elderly.

The accuracy of reagent strip testing for urinary tract infection (UTI) was assessed in 100 elderly patients (50 acute patients admitted to hospital and 50 attending the day hospital). Reagent strip sensitivities were: acute patients-urinary nitrite 83%, blood 67%, protein 72% and leucocytes 72%, and day hospital patients-urinary nitrite 90%, blood 65%, protein 30% and leucocytes 60%. Urinary nitrite specificities were 100% for both groups of patients. Only 28% of patients with a UTI had specific symptoms of the infection; pyrexia and a raised WBC also proved poor indicators. Urinary nitrite was thus the most accurate immediate indicator of UTI.

Aged↗

PubMed1990

A clinical comparison of the performance of four blood glucose reagent strips.

The widespread use of visually read blood glucose reagent strips for initiation of emergent treatment of hypoglycemia and hyperglycemia has produced concern over the accuracy of this method. This study evaluated the accuracy of Chemstrip bG (Bio-Dynamics, Boehringer Mannheim, Indianapolis, IN), Dextrostix (Ames, Miles Laboratories, Elkhart, IN), Glucostix (Ames), and Visidex II (Ames) as compared with hospital laboratory values in an emergency department (ED) setting. Blood samples from 96 ED patients were tested for glucose concentration by each of the four strips and by the hospital laboratory. Each strip was evaluated for sensitivity, specificity, correlation coefficient (r), 95% confidence intervals, and kappa statistic (kappa, a measure of agreement between nonparametric data) using laboratory values as reference. In addition, six observers scored each strip for ease of interpretation using an ordinal scale of 1 (poor) to 4 (excellent). From the samples, no patients were hypoglycemic (less than or equal to 60 mg/dL), 83 were euglycemic (greater than 60 and less than 160 mg/dL), and 13 were hyperglycemic (greater than or equal to 160 mg/dL). Results suggest that over the range of glucose concentration sampled, there is good to excellent correlation with laboratory values for all strips except Dextrostix. The lower r value for Dextrostix is in part artifact due to limitation of its range of measurement to less than or equal to 250 mg/dL. Decreased accuracy for all strips in the hyperglycemic range may have been attributable to small sample size. Chemstrip bG and Visidex II were found to be subjectively easier to interpret.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗

PubMed1975

Microstix-A reagent strip for urine culture.

Microstix is a simple and convenient reagent strip for obtaining a semi-quantitative bacterial count on urine specimens. This method correctly predicted over 10(5) gram-negative organisms per ml in 84 percent of samples and over 10(5) gram-positive organisms per ml in 72 percent. Urine specimens containing 10(4) per ml or more of any organism should be recultured using fully quantitative methods. If this criterion had been used 89 percent of urine samples with over 10(5) organisms per ml would have been detected with Microstix and only 33 of the 393 remaining samples would need to have been repeated. The false positive rate was low. This method would be ideal for use in doctors' offices to culture the urine of patients presenting with urinary tract symptoms. It would also be very suitable for use in hospital clinics and for the screening of asymptomatic populations who are high risk of having urinary tract infections.

Bacteriological Techniques↗

PubMedDate not supplied

Are blood glucose reagent strips reliable in renal failure?

In vitro studies have suggested that a low packed cell volume may cause reagent strips to overestimate blood glucose concentration. The reliability of such strips has therefore been investigated in diabetic patients with end-stage renal failure, all of whom had low haematocrits (24 +2- 4 (4/- SD) %). Three brands of strips were evaluated and their results were compared with laboratory whole blood glucose concentrations determined on the same samples. All over-read compared with the laboratory (BM Glycemie 1-44 strips 118 +/- 1%, Glucostix 132 +/- 2%, ExacTech strips 163 +/- 4%) and the percentage overread was negatively correlated with the haematocrit for each strip (all p less than 0.001).

Blood Glucose↗

PubMed1977

Urinalysis by use of multi-test reagent strips: two dipsticks compared.

We compared Ames' "N-Multistix" with Boehringer's "Combur-8" ("Chemstrip-8") multi-test urine reagent strips by analysis of contrived urine specimens, testing accuracy, precision, specificity, and limits of detection of both products. Relative cost and ease of use were also examined. Each brand of urinary dipstick had specific advantages but it is unlikely that patient care would be adversely affected by preferential use of either product.

Acetoacetates↗

PubMed1987

Reagent strips in the evaluation of cerebrospinal fluid glucose levels.

The value of Visidex IIR, Haemo-Glukotest 20-800RR, MultistixR and DextrostixR reagent strips--the latter alone or in combination with a glucometer--in the determination of cerebrospinal fluid (CSF) glucose levels has been evaluated and compared with the results of a standard glucose oxidase method (Beckman). Fifty-four CSF specimens were evaluated and the closest correlation (r = 0.8002) obtained by the use of DextrostixR in combination with a glucometer. All four methods detected two cases with very low CSF glucose values (less than 1.5 mmol/l) but confusing results were obtained in three cases having slightly reduced CSF glucose values (2.0-2.2 mmol/l).

Child↗

PubMed1976

Evaluation of an improved Reagent Strip system for measuring blood glucose.

Using a new, synthetic whole-blood control and an improved reflectance meter, the within-run precision of Dextrostix Reagent Strips for quantitative determination of blood-glucose levels is compared with three common manual methods (hexokinase, o-toluidine, and glucose oxidase), and one automated method (neocuproine-AutoAnalyzer). In addition, the strip is compared on a day-to-day basis with the o-toluidine method. Dextrostix, used with the new instrument and control, provides results that compare very well with the other methods for within-run precision, and with the o-toluidine method for day-to-day results.

Blood Glucose↗

PubMed1976

A comparison of enzyme reagent strip tests for lacrimal glucose.

Lacrimal glucose screening for diabetes mellitus is becoming increasingly popular in optometric practice. Several commercial glucose test kits are available and can be used for this purpose. This paper compares the cost, reaction range, and reaction time reported for six different types of reagent strip tests.

Costs and Cost Analysis↗