Paper 057, IAEA 2006 Teachers’ assessment practices… Dr Rita Berry 32nd International Association for Educational Assessment (IAEA) Annual Conference Theme: Assessment in an Era of Rapid Change: Innovations and Best Practices 21 – 26 May 2006 Grand Copthorne Waterfront Hotel, Singapore Affiliation: Hong Kong Institute of Education Department of Curriculum
Nitrite: - Intended to identify nitrite in urine. Nitrite identifi cation is used in the diagnosis and treatment of
urinary tract infections of bacterial origin. The color test is based on the principle of the Griess reaction. Any degree of pinkorange coloration should be interpreted as a positive nitrite test suggestive of ≥105 organisms/ml For In-Vitro Diagnostic Use
urine. Negative results do not exclude signifi cant bacteriuria (insuffi cient incubation, urinary tract infections Urine Test Strips for the Rapid Determination of Ascorbic Acid, Bilirubin, Blood, Glucose, Ketones, Leucocytes, due to bacteria not containing nitrate reductase). Before testing the patient should ingest vegetable-rich Nitrite, pH-value, Protein, Specifi c Gravity and Urobilinogen. Refer to the carton and label for specifi c parameter meals, reduce fl uid intake and discontinue antibiotic and vitamin C therapy 3 days prior to the test. False combination on the product you are using.
positive results may occur in stale urines, in which nitrite has been formed by contamination of the specimen and in urines containing dyes (derivatives of pyridinium, beetroot). A negative result even in the presence Intended Use
of bacteriuria can have the following reasons: bacteria not containing nitrate reductase, diet with low nitrate For use as a preliminary screening test for diabetes, liver diseases, haemolytic diseases, urogenital and kidney content, high diuresis, high content of ascorbic acid or insuffi cient incubation of the urine in the bladder. Red disorders and metabolic abnormalities.
or blue borders or edges which may be present must not be interpreted as a positive result. Values of 0,05-0,1 Procedure and Notes
pH: - Intended to estimate the pH of urine. Estimations of pH are used to evaluate the acidity or alkalinity of
• Use only well mixed, non-centrifuged urine, which should not be older than 4 hours. First morning urine is urine as it relates to numerous renal and metabolic disorders and in the monitoring of patients with certain diets. recommended. Protect the samples from light.
Persisting high pH-values indicate urinary tract infections. The test paper contains indicators which clearly • If the samples cannot be tested immediately, they should be stored at 2.4°C and brought to room change color between pH 5 and pH 9 (from orange to green to turquoise). The pH value of fresh urine of temperature (15.25°C) before testing.
healthy people varies between pH 5 and pH 6. Bacterial contamination may lead to false results. Red borders • Collect specimen in clean, well rinsed containers, free of detergents. Do not add any preservatives.
which may be present in neighbourhood to the nitrite fi eld must not be taken into consideration The color fi elds correspond to the following pH values: 5, 6, 7, 8, 9.
• Do not touch test areas of the reagent strip.
• Immediately after removing the required number of strips, close the container securely using the original Protein: - Intended to identify proteins in urine. Identifi cation of urinary protein is used in the diagnosis
and treatment of renal diseases. The test is based on the „protein error“ principle of the indicator. The test is especially sensitive in the presence of albumin. Other proteins are indicated with less sensitivity. Normally, • Immerse the test strip in the urine (approx. 2 sec), so that all reagent areas are covered. Remove excess no protein is detectable in the urine of healthy subjects. Falsely positive results are possible in highly alkaline urine from the strip by wiping the edge of the strip on the urine container or on absorbent paper.
urine samples (pH > 9) and in the presence of high specifi c gravity, after infusions with polyvinylpyrrolidone • To prevent interaction from adjacent test areas, hold the strip in a horizontal position during incubation.
(blood substitute), after intake of medicaments containing quinine and also by disinfectant residues containing • Compare the reagent areas on the strip with the corresponding color chart on the container 60 seconds (60 quaternary ammonium groups in the urine sampling vessel. The color fi elds correspond to the following ranges – 120 seconds for leucocytes) after immersion. Coloration only on the rim of the test pad or after more than of albumin concentrations: negative, 30, 100 and 500 mg/dl or negative, 0.3, 1.0 and 5.0 g/l. Values of approx. 2 minutes after immersion is without meaning and should not be used for interpretation.
15 mg/dl Albumine are indicated.
Specifi c Gravity / Density: - Intended to provide an estimation of renal ability of urine concentration or
Clinical Utility, Test Principles, Expected Values, Limitations
urine dilution. The specifi c gravity of urine varies in accordance with the drinking quantity as well as different Ascorbic Acid: - Intended to measure the level of ascorbic acid (vitamin C) in urine. The detection is based
disorders. A highly diluted urine e.g., a SG of approx.1.000 can indicate a failure of the renal concentration on the decoloration of Tillmans reagent. In the presence of ascorbic acid a color change takes place from ability. In addition, the determination of specifi c gravity is also important indicator for a manipulation (e.g., urine grey blue to orange. As ascorbic acid already in low concentrations can disturb various test fi elds, especially dilution of sample) at the screening for drug abuse. The test is based on a color change of the reagent from blue the glucose assay in low concentrations, the test must be repeated if the ascorbic acid reaction is positive, green to greenish yellow depending on the concentration of ions in the urine. The test permits the determination however, at the earliest 10 hours after the last vitamin C intake (medication, fruit, vegetables). Values of 5 – 10 of urine density between 1.000 and 1.030. The normal value varies between 1.015–1.025. The color scale has mg/dl or 0,6 – 1,1 mmol/l are indicated.
been optimized at a pH of the urine of 6. Highly alkaline (pH > 8) urines lead to slightly low results, highly acid Bilirubin: - Intended to measure the levels of bilirubin conjugates in urine. Measurements of urinary bilirubin
(pH < 6) urines may cause slightly higher results. Glucose and urea do not interfere. The color fi elds correspond and its conjugates are used in the diagnosis and treatment of certain liver and bile diseases. A red azo to the values of 1,000; 1,005; 1,010; 1,015; 1,020; 1,025; 1,030.
compound is obtained in the presence of acid by coupling of bilirubin with a diazonium salt. Normally, no Urobilinogen: - Intended to detect and estimate urobilinogen (a bile pigment degradation product of red
bilirubin is detectable in urine. Concentrations of 0,5 mg/dl and more lead to a color of red-orange peach and cell hemoglobin) in urine. Estimations obtained by this device are used in the diagnosis and treatment of liver indicate the early stage of a liver disease. The reaction is unaffected by pH of urine. False low or negative diseases and hemolytic (red cells) disorders. The test is based on the coupling of urobilinogen with a stabilised results may be simulated by large amounts of vitamin C or Nitrite or by longer exposure of the sample to direct diazonium salt to a red azo compound. The normal concentration of urobilinogen in urine goes from 0.1 – 1.8 light. Increased concentrations of urobilinogen can reinforce the sensitivity of the test fi eld. Different urine mg/dl (1.7 – 30 µmol/l). Concentrations of > 2.0 mg/dl (35 µmol/l) are considered to be pathological. The contents (e.g. urine indicane) can lead to atypical coloration. For metabolites of drugs see urobilinogen. The reaction is unaffected by pH of urine. Higher concentrations of formaldehyde or exposure of the urine to light for color fi elds correspond to the following values: 0 (negative), 1(+), 2(++), 4(+++) mg/dl or 0 (negative), 17(+), a longer period of time may lead to lowered or falsely negative results. Beetroot or metabolites of drugs which 35(++), 70(+++) µmol/l. Values of 0,5 – 1 mg/dl Bilirubin are indicated.
give a color at low pH (phenazopyridine, azo dyes, p-aminobenzoic acid) may cause false positive results. The color fi elds correspond to the following urobilinogen concentrations: norm. (normal), 2, 4, 8, 12 mg/dl or norm. Blood: - Intended to detect occult blood in urine. Occult blood indicates serious urological or kidney
diseases. Microhaematuria does not affect the colour of urine and is only detectable by microscopic or chemical tests. The detection is based on the pseudoperoxidative activity of hemoglobin and myoglobin, which catalyze the oxidation of an indicator by an organic hydroperoxide and a chromogene producing a Reagent Composition in the Tests
Ascorbic acid: 2,6-dichlorophenolindophenol 0,7% green color. Ascorbic acid does virtually not infl uence the test result. Falsely positive reactions can also be produced by a residue of peroxide containing cleansing agents, activities of microbial oxidase due to Blood: tetramethylbenzidine-dihydrochloride 2,0%, isopropylbenzol-hydroperoxide 21,0% infections of the urogenital tract or by formaline. The signifi cance of a positive result varies from patient to Glucose: glucose oxidase 2,1%; peroxidase 0,9%; o-tolidine-hydrochloride 5,0% patient. For establishing an individual diagnosis, it is therefore indispensable to take into consideration also the clinical manifestations. The number of erythrocytes which are detected by sediment analysis may be Leucocytes: carboxylic acid ester 0,4%; diazonium salt 0,2% lower than the result of the test strip, because lysed cells are not detected by sediment analysis. The color Nitrite: tetrahydrobenzo[h]quinolin-3-ol 1,5%; sulfanilic acid 1,9% fi elds correspond to the following values: 0 (negative), approx. 5-10, approx. 50, approx. 300 Ery/µl. Values pH: methyl red 2,0%; bromothymol blue 10,0% of approx. 5 Erythrocytes/µl are indicated.
Glucose: - Intended to measure glucosuria (glucose in urine). Urinary glucose measurements are used in the
diagnosis and treatment of carbohydrate metabolism disorders including diabetes mellitus, and hyperglycemia. The detection is based on the glucoseoxidase-peroxidase-chromogen reaction. Apart from glucose, no other compound in urine is known to give a positive reaction. Normally, glucose cannot be detected in the urine Storage and Stability
although small amounts are secreted also by the healthy kidney. Changes in the coloration less than 50 mg/dl Keep diagnostic test strips protected from direct sunlight and humidity. Store the tubes in a cool and dry place (2.8 mmol/l) are to be considered normal. The infl uence of ascorbic acid has been largely eliminated. From a (storage temperature 2.30°C). Under proper conditions test strips are stable up to the stated expiry date.
glucose level at 100 mg/dL (5,5 mmol/L) and above, even at high concentrations of ascorbic acid no negative results are observed. An inhibitory effect is produced by gentisic acid, a pH value of <5 and high specifi c • In order to establish a fi nal diagnosis and prescribe an appropriate therapy, the results obtained with test gravity. False positive reactions can also be produced by a residue of peroxide containing cleansing agents or strips should be verifi ed with other medical results.
others. The color fi elds correspond to the following ranges of glucose concentrations: normal, 50, 100, 250, 500 • The effect of medicaments or their metabolic products on the test is not known in all cases. In case of doubt and 1000 mg/dl or normal, 2,8, 5,6, 14, 28 and 56 mmol/l. Values of 40 mg/dl glucose are indicated.
it is recommended not to take the medicaments and then repeat the test. However, stopping taking the drugs Ketones: - Intended to detect ketones in urine. Identifi cation of ketones is used in the diagnosis and
should only be done after respective instruction of the doctor.
treatment of acidosis (a condition characterized by abnormally high acidity of body fl uids) or ketosis (a condition • Due to the fact that the content of the urine is not constant (e.g. content of activators or inhibitors which may characterized by increased production of ketone bodies) and for monitoring patients with diabetes. Acetone vary from sample to sample, changing ion concentration), the conditions of the reaction are not always the and acetoacetic acid react with sodium nitroprusside in alkaline solution to give a violet colored complex same which may lead to variations of the intensity and the color in rare cases.
(Legal‘s test). Normally the urine is free of ketones. Detectable concentrations of ketones can originate from • For refl ectometric reading, please read carefully the detailed instructions for use of the instruments. As a physiological stress (fasting, pregnancy, excessive sport). Phenylketones in higher concentrations will produce result of the differing spectral sensitivities of the human eye and the optical system of the instruments, it is variable colors. β-Hydroxybutyric acid is not detected. Phthalein compounds and derivatives of anthrachinone not always possible to obtain precise agreement between the values obtained by visual reading and those interfere by producing a red coloration in the alkaline range which may mask the coloration of ketones. The color fi elds correspond to the following acetoacetic acid values: 0 (negative), 25(+), 100(++) and 300(+++) • For handling of the test strips, please observe the general working instructions for laboratories.
mg/dl or 0 (negative), 2.5(+), 10(++) and 30(+++) mmol/l. Values of 5 mg/dl acetoacetic acid or 50 mg/dl • For in vitro diagnostic use only. For trained staff only – not for self testing.
• Avoid swallowing and contact with eyes and mucous membranes. Keep away from children.
• Each laboratory should evaluate it’s own standards for quality control.
Leucocytes: - Intended to detect leucocytes in urine. Leucocytes indicate infl ammatory diseases of the
• Literature: Thomas L.; Clinical Laboratory Diagnosis, TH-Books, Frankfurt/Main 1998 kidneys and the urinary tract, and suggests need for further investigation. The test is based on the esterase • Refer to the carton and label for package size.
activity of granulocytes. This enzyme splits heterocyclic carboxylates. The component released reacts with a diazonium salt producing a violet color. Urines of healthy subjects do not contain any leucocytes. Positive results, even when constantly varying from „negative“ to „25“, are to be considered as clinically relevant. Strongly = read package insert; = Expiry; = Store at; colored compounds (e.g. nitrofurantoin) may disturb the color of the reaction. Glucose or oxalic acid in high = this product is conform to the directive 98/79EG dated 27.10.1998; concentrations, drugs containing cephalexine, cephalothine or tetracycline can lead to weakened reactions. = LOT Number; REF = catalogue number
Falsely positive results may be caused by contamination with vaginal secretion. The number of leucocytes which are detected by sediment analysis may be lower than the result of the test strip, because lysed cells are analyticon® Biotechnologies AG
not detected by sediment analysis. The color fi elds correspond to the following values: 0 (negative), approx. 35104 Lichtenfels, Germany
25, approx. 75, approx. 500 Leuko/µl. Values of 10-20 leucocytes/µl are indicated.
INTRODUCTION Guide to Contraindications to Vaccination This guide is designed to help immunization providers determine what common symptoms and conditions should contraindicate vaccination and which ones should not. It supersedes the 2000 Guide to Contraindications to Childhood Vaccination and, unlike that and previous Guides, contains information on all licensed U.S. vaccines, not just ped