Ketone Reagent Strips/Test Information and Procedure
Reagent Strips for Urinalysis
SUMMARY AND EXPLANATION: |
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EXPECTED VALUES: |
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The strips provide a fast, convenient way of testing urine for the presence and concentration of acetoacetic acid (ketone). This substance when found in the urine provides information on carbohydrate and fat metabolism.1,2
Acetoacetic acid can be found in the urine from diabetics and is more commonly referred to as a “ketone body.” Use of KETONE Reagent Strips can alert you and your doctor or diabetes educator to changes in your condition for which adjustments in your diet and/or medication may be needed. Carefully follow the testing schedule your doctor or educator establishes.
CHEMICAL PRINCIPLES OF THE PROCEDURE:
The ketone test is specific for acetoacetic acid and is based on the development of colors ranging from buff-pink to maroon when acetoacetic acid reacts with nitroprusside.
REAGENTS:
7.1% w/w sodium nitroprusside; 92.9% w/w buffer.
WARNINGS AND PRECAUTIONS:
KETONE Reagent Strips are for in vitro diagnostic use. They have been determined to be nonhazardous under the guidelines issued by OSHA in 29CFR 1910.1200(d).
STORAGE AND HANDLING:
Never use KETONE Reagent Strips past the expiration date printed on the bottle label.
To keep KETONE Reagent Strips fresh, follow these suggestions carefully. Keep your finger or other objects from touching the reagent area before testing. Store at room temperatures between 59°– 86°F (15°– 30°C). Do not store the bottle in direct sunlight.
Keep unused reagent strips in the original bottle with the cap tightly closed. Always replace the cap immediately and tightly after removing a strip. A new bottle of strips can be used for six months after being first opened. Always write the date you first opened the bottle on the bottle label. Do not use product (opened or unopened) after expiration date. Use of strips beyond the expiration date may yield low results. Never transfer reagent strips to another bottle. Do not remove desiccant from bottle. The desiccant absorbs moisture and keeps the strips dry. Never put cotton or other materials in the bottle. If the reagent area is ever discolored or darkened, throw the strip away and use a strip from a new bottle.
SPECIMEN COLLECTION AND PREPARATION:
Collect fresh urine in a clean, dry container and test it as soon as possible, or alternatively, pass the reagent pad through the urine stream. If testing cannot be done within an hour after collecting a urine specimen, refrigerate the specimen immediately and let it return to room temperature before testing.
RESULTS:
Results with KETONE Reagent Strips are obtained directly from comparison to the Color Chart. The color blocks represent nominal values; actual values will vary around the nominal values.
Ketone results are read from the Color Chart as negative or varying degrees of positive which indicate the relative amounts of ketone (acetoacetic acid) present. The color blocks represent Negative, Trace (5 mg/dL), Small (15 mg/dL), Moderate (40 mg/dL) and Large (80–160 mg/dL). Proper read time is critical for optimal results.
The ketone reagent area is most accurate when testing urines of specific gravity between 1.010 and 1.020.
IF TEST RESULTS SEEM QUESTIONABLE:
1.Check the EXPIRATION DATE printed on the bottle label. If the date has passed, discard and retest with strips from a new bottle. Check the date you first opened the bottle and if 6 months have passed, throw the strips away and use a new bottle of KETONE Reagent Strips.
2.Test the urine again with a strip from a new bottle and compare results. If a problem cannot be identified or corrected, call our Customer Service Department, toll free 1-800-348-8100 or consult your doctor, diabetes educator, pharmacist or Self Testing Center for advice on testing technique and results.
Normal urine specimens ordinarily yield negative results with the KETONE reagent area. Detectable levels of ketone may occur in urine during physiological stress conditions such as fasting, pregnancy and frequent strenuous exercise.3,5 In ketoacidosis, starvation or other abnormalities of carbohydrate or fat metabolism, ketones may appear in urine in large amounts before serum ketone is elevated.6
LIMITATIONS OF PROCEDURES:
As with all laboratory tests, definitive diagnostic or therapeutic decisions should not be based on any single result or method. KETONE results should never be used as the sole basis for adjusting insulin dosage.
Substances that cause abnormal urine color, such as drugs containing azo dyes (e.g., Pyridium®*, Azo Gantrisin®*, Azo Gantanol®*), nitrofurantoin (Macrodantin®*, Furadantin®*), and riboflavin, may affect the readability of the ketone reagent area on the KETONE Reagent Strips. The color development on the reagent pad may be masked, or a color reaction may be produced on the pad that could be interpreted as a false positive.
False positive results (Trace or less) may occur with highly pigmented urine specimens or those containing large amounts of levodopa metabolites. Compounds such as mesna (2-mercaptoethane sulfonic acid) that contain sulfhydryl groups may cause false positive results or an atypical color reaction.
SPECIFIC PERFORMANCE CHARACTERISTICS:
Specific performance characteristics are based on clinical and analytical studies. In clinical specimens, the sensitivity depends upon several factors: the variability of color perception; the presence or absence of inhibitory factors typically found in urine, the specific gravity, and the pH (see LIMITATIONS OF PROCEDURES section); and the lighting conditions under which the product is read. Because the color of each reagent area changes as the analyte concentration increases, the percentage of specimens detected as positive will increase with the analyte concentration.
Each color block represents a range of values. Because of specimen and reading variability, specimens with analyte concentrations that fall between nominal levels may give results at either level. Results at levels greater than the second positive level will usually be within one level of the true concentration.
The test reacts with acetoacetic acid in urine. It does not react with acetone or beta-hydroxybutyric acid. In a majority of cases, the reagent area detects 5 to 10 mg/dL acetoacetic acid. Some high specific gravity-low pH urines may give reactions up to and including Trace (5 mg/dL). Clinical judgment is needed to determine the significance of reactions up to and including Trace.
AVAILABILITY:
KETONE Reagent Strips in bottles of 50 strips (#2523) are available only at Wal-Mart and SAM’s Club pharmacies.
REFERENCES:
1.Cecil, R. L. and Loeb, R. F.: A Testbook of Medicine, W. B. Saunders, Co., Philadelphia, 1959, 10th ed., pp 618-619.
2.Engel, F. L. and Amatruda, T. T.: Ann. N. Y. Acad. Sci. 104, Art 2, 753-771 (1963).
3.McGarry, J. D., Lilly, Lecture 1978: New Perspectives in the Regulation of Ketogenesis. DIABETES 28, May, 1978, 517-523.
4.Williamson, D. H.: Physiological ketoses, or why ketone bodies?
Postgraduate Medical Journal (June Suppl. 1971), 371-375.
5.Paterson, P., Sheath, J., Pincus, T. and Wood, C.: Maternal and Fetal Ketone Concentrations in Plasmas and Urine, The Lancet: April 22, 1967, 862-865.
6.Fraser, J., Fetter, M.C., Mast, R. L. and Free, A. H.: Studies with a Simplified Nitroprusside Test for Ketone Bodies in Urine, Serum, Plasma and Milk,
Clin. Chem. Acta II (1965) 376-378.
*Trademarks
Pyridium® is a registered trademark of Parke-Davis.
Azo Gantrisin® and Azo Gantanol® are registered trademarks of Roche Laboratories.
Macrodantin® and Furadantin® are registered trademarks of Procter & Gamble Pharmaceuticals, Inc.
Manufactured by: Bayer HealthCare LLC Mishawaka, IN 46544
AN13216A USA |
© 2004 Bayer HealthCare LLC |
Rev. 7/04 |
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