Phosphorus Test Code: PHOS

Transcription

1 Intended Use Phosphorus Test Code: PHOS For in vitro diagnostic use only CARESIDE cartridges are used with the CARESIDE Analyzer to quantitatively measure inorganic phosphorus in anticoagulated whole blood, plasma or serum specimens. The CARESIDE Phosphorus test aids in the diagnosis and treatment of various disorders including those of the parathyroid gland and kidney as well as vitamin D imbalance. CARESIDE Phosphorus, a single use cartridge, aids in specimen separation and delivers a measured volume of sample to a dry film to initiate the measurement of inorganic phosphorus concentration. The film cartridge (patent pending) contains all reagents necessary to measure phosphorus concentration. Test Summary Phosphorus is required for generation of bony tissue and functions in the metabolism of glucose and lipids, in the maintenance of acid-base balance, and in the storage and transfer of energy from one site in the body to another. Blood phosphorus levels must be controlled within narrow limits 1. Measurements of inorganic phosphorus are used in the diagnosis and treatment of various disorders including parathyroid gland and kidney diseases, and vitamin D imbalance. Phosphorus levels are always evaluated in relation to calcium levels because an inverse relationship exists between the two. The risk of arrhythmia and muscle twitching increases greatly when phosphorus rises rapidly and calcium drops. An excess serum level of one causes the kidneys to excrete the other 1. Hypophosphatemia may be seen in hyperparathyroidism, Fanconi s syndrome, vitamin D deficiency in children (rickets) and adults (osteomalacia), chronic use of antacids, chronic alcoholism, malabsorption syndromes, hyperinsulinism and occasionally during hyperalimentation therapy. Causes of hyperphosphatemia include chronic renal failure, Addison s disease, excessive ingestion of vitamin D, cytotoxic treatment of certain leukemias and lymphomas, metastatic bone tumors, hypocalcemia, diabetic ketoacidosis, and healing bone fractures. Test Explanation Each CARESIDE Phosphorus cartridge consists of a phosphorus-specific multi-layer reagent film mounted in a plastic base with a hinged lid. The user introduces the patient sample into the cartridge Sample Well, closes the lid and inserts the cartridge into the CARESIDE Analyzer. Once loaded, the CARESIDE Analyzer scans the cartridge barcode and spins the cartridge to move the sample from the Sample Well into the cartridge channels and chambers. While spinning, the cartridge and the contained specimen are warmed to 37 C. As the cartridge continues to spin, the blood cells (if present) are separated from the plasma/serum and the cells accumulate in the separation well. Any excess sample flows into an

2 overflow well, leaving the required volume in the metering passage. The sample in the metering passage is automatically dispensed onto the multi-layer reagent film. The spreading layer distributes the sample evenly on the film, and the sample moves through a reaction layer where a blue dye forms in the presence of phosphate. As the cartridge spins, photodiodes measure film reflectance of light emitted from wavelengthspecific light emitting diodes (LEDs) at fixed times. The instrument uses the reflectance measurements and the lot-specific standard curve to calculate phosphorus concentration. Test Principle The metered sample is delivered onto the spreading layer where it is distributed uniformly. As the sample passes into the reaction layer, large molecular weight components, such as proteins, are removed. Purine nucleoside phosphorylase (PNP) then catalyzes the reaction of the inorganic phosphate (H PO 4 -, HPO 4 - ) with xanthosine to form xanthine and ribose-1-phosphoric acid. Xanthine oxidase (XOD) catalyzes the oxidation of xanthine in the presence of water and oxygen to produce uric acid and hydrogen peroxide. Finally peroxidase (POD) catalyzes the conversion of a leuco dye and hydrogen peroxide to produce imidazole blue dye and water. The intensity of the color as measured by the amount of reflected light at 655 nanometers directly relates to the inorganic phosphorus concentration in the sample. Test Reaction Sequence PNP Xanthosine + inorganic phosphate Xanthine + Ribose-1-phosphoric acid Xanthine + H O + O H O + Leuco dye XOD Uric Acid + H O POD Imidazole Blue Dye + H O Test Element Architecture Cartridge Top Phosphorus Lid Cartridge Body Spreading Layer Reaction Layer Transparent Support on Film Window Test Cartridge Ingredients The active ingredients are xanthosine, purine nucleoside phosphorylase, diarylimidazole leuco dye, xanthine oxidase, and peroxidase. Test Warnings and Precautions For in vitro diagnostic use only. Use the phosphorus cartridge within 15 minutes of opening. Handle all patient samples, QC materials of human origin, and dosed test cartridges using universal precautions 3. Protect reagent film from contamination or excessive light. Do not touch; touching the film can cause optical errors. Do not reuse cartridges. Specimens should be free from precipitates. Test Cartridge Storage & Preparation Cartridges are stable until the date printed on the cartridge label when stored at to 8 C (36 to 46 F). Do not use if the package has been opened or damaged, or if the package seal is not intact. Unused cartridges may be returned to refrigerated storage if they are unopened. Test Calibration No routine user calibration is required. Each cartridge lot is factory calibrated and the calibration information is read automatically by the CARESIDE Analyzer. Specimen Collection The CARESIDE Phosphorus cartridge is intended for use with appropriately collected anti-coagulated

3 whole blood, plasma or serum, and requires 90 ± 10µL sample per test cartridge. Collect blood using standard venipuncture technique 4. Patient Preparation No special patient preparation is necessary. Whole blood Collect whole blood in blood collection tubes containing sodium heparin or EDTA. Do not use sodium fluoride, citric acid, oxalic acid, or monoiodoacetic acid. Mix anticoagulant according to manufacturer s instructions allowing sufficient time for anticoagulation to occur. Serum Collect blood in the absence of anti-coagulant. Allow blood to fully clot at room temperature. Centrifuge the clotted blood and separate the serum promptly from the clot. Plasma Collect whole blood using anticoagulant as described under Whole Blood, above. Promptly centrifuge the blood and separate the plasma from the cells. Specimen Handling and Preparation Specimens may be stored at room temperature when tested within 4 hours of draw. If analysis is not performed within 4 hours, refrigerate samples at to 8 C. If testing is delayed beyond 48 hours, freeze serum or plasma specimens at -0 C or colder 5. Thoroughly mix stored specimens before testing. Do not freeze whole blood. Do not dilute specimens for routine testing. To obtain results for patients that have phosphorus levels above the reportable range, dilute only serum or plasma samples. Do not dilute whole blood specimens. Use normal saline to perform a twofold dilution (1 part sample, 1 part normal saline), and multiply the result by. Test Procedures 1. Select the test to be performed on the CARESIDE Analyzer.. To dose the cartridge, lift the test cartridge lid by lifting up on the side clips. To the Sample Well apply 90 ±10µl of sample or fill the well internally. An exact volume is not required, since the test cartridge will meter the correct volume. Do not allow the specimen to spill over the well. Any sample outside of the well must be completely removed before proceeding. 3. Close the cartridge lid firmly until it clicks indicating closure. 4. Load the dosed test cartridge into the CARESIDE Analyzer and press Confirm (see the CARESIDE Analyzer Operator s Manual for more information). Quality Control Each CARESIDE test cartridge barcode contains all required calibration information. The CARESIDE Analyzer scans the barcode, continuously performs quality control self-checks during operation, and alerts and prevents the user from proceeding if an unacceptable condition exists. At a frequency determined appropriate by the user s institution, evaluate instrument performance using two levels of phosphorus controls. Contact CARESIDE Technical Service for a list of commercial control products compatible with the CARESIDE Analyzer. Each institution should establish quality control ranges using the CARESIDE Analyzer and monitor test performance using a Levey-Jennings chart (See CARESIDE Analyzer Operator s Manual). Results Results require no user calculation and appear on the CARESIDE Analyzer screen, as they become available. Reporting Units: mg/dl Conversion Factor: mmol/l = 0.33 x mg/dl Reportable Range: 0.5 to 15 mg/dl Expected Values (Reference Interval) The following reference interval was obtained by non-parametric analysis of fasting specimens from a population of 5 healthy adults in the United States using the CARESIDE Phosphorus test. 3 Central 95% interval:. to 4.4 mg/dl

4 The observed reference interval is similar to the published serum reference interval,.5 to 4.5 mg/dl 4. Expected values may vary depending upon the population of subjects. It is recommended that each institution establish values for the population they serve. Limitations A result outside the reportable range or any result not consistent with the clinical picture should be repeated to confirm. Performance Characteristics Detection Limit The CARESIDE Phosphorus has a lower detection limit of 0.5 mg/dl. Accuracy CARESIDE Phosphorus concentration agrees with an endpoint photometric method for phosphorus using ammonium molybdate as substrate. CARESIDE (mg/dl) Phosphorus Method Comparison Slope = 0.99 Intercept (mg/dl) = 0.03 Correlation Coefficient = 1.00 Range of values = 0.7 to 15 n = Photometric Method (mg/dl) Precision Human serum based controls (representing a low, middle and high phosphorous concentration) were tested in duplicate in at least 0 runs over a period of at least 3 days. Results are shown in the following table. CARESIDE Phosphorus Precision 1 3 Mean Conc. (mg/dl) Within-run SD (mg/dl) Within-run CV (%) Total SD (mg/dl) Total CV (%) Actual precision may vary from site-to-site and from results indicated in this test insert. Each facility should verify that on-site product precision is appropriate for the site. Interference No significant interference was observed up to the levels indicated for the following substances: Interferent Concentration Ascorbic Acid 10 mg/dl Bilirubin 0 mg/dl Hemoglobin 100 mg/dl Triglyceride 1500 mg/dl Bibliography 1. Frances Talaska Fischabach, Manual of Laboratory and Diagnostic Tests, Willard R. Faulkner and Samuel Meites, Selected Methods for the Small Clinical Chemistry Laboratory, American Association for Clinical Chemistry, U.S. Department of Health and Human Services, Biosafety in Microbiological and Biomedical Laboratories. HHS Publication (NIH) Washington: U.S. Government Printing Office, May Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture. National Committee for Clinical Laboratory Standards. H3-A3; Burtis, C.A & Ashwood, E.R., Tietz Textbook of Clinical Chemistry, nd Edition, W.B. Saunders Company Technical Assistance If questions arise concerning the CARESIDE Analyzer or test cartridges, please contact CARESIDE Technical Service. Telephone: (888) 698-CARE (73) (310)

5 Fax: (310) Ordering Information For product ordering or general information, please contact CARESIDE Customer Service. Telephone: (888) 698-CARE (73) (310) Fax: (310) CARESIDE, Inc Bristol Parkway PI-PHOS-B Culver City, CA Jun-000