Glucostix Reagent Strips

The Glucostix reagent strips are used for blood glucose tests, for visual use or for use in Bayer Glucometers.

Description:

These are disposable firm plastic reagent strips with two reagent pads for determining the concentration of glucose in whole blood. A semi-permeable membrane serves as a barrier to blood cell migration into the reagent area.

The reagent strip can either be interpreted visually or be read instrumentally by a Glucometer II blood glucose meter (a reflectance colorimeter), Gluco-meter II with memory or Gluco-meter M. A large drop of blood is placed on the Glucostix test pads, timed as directed, then blotted and inserted either into the instrument or read visually from the color blocks found on the Glucostix bottle label.

The Glucostix Reagent Strip measures blood glucose levels quanti-tatively from 2-22\mmol/L (40-399\mg/dL) using the blood glucose meter, or semi-quantitatively from 0-44\mmol/L (0-800\mg/dL) by comparing the reacted color on the Glucostix reagent pads to the color chart on the bottle.

The program number is for instrument use only. The instrument is required to be programmed to match the chemical reactivity of each bottle of reagent strips. This is done by pressing the program button on the Glucometer II, Glucometer II with memory, Glucometer M or Glucometer GX meter until the number appearing in the instrument display window matches the number that appears on the bottle label of the Glucostix Reagent Strips being used. Programming calibrates the instrument to read the strip accurately. Instrument programming needs to be done only when a new bottle of strips is first opened, or when a new battery is inserted into the instrument.

Principles

Lower and higher range reagent pad reactions of Glucostix Reagent Strips are based on the action of the enzyme glucose oxidase, that is specific for glucose. Glucose oxidase catalyses the oxidation of glucose in blood by oxygen in the atmosphere, producing gluconic acid and hydrogen peroxide. In the presence of peroxidase, the ortho-/tolidine in the reduced form is oxidised by the hydrogen peroxide producing a shade of green color on the lower range pad with an intensity proportional to the glucose concentration. On the higher range pad, in the presence of peroxidase, the amino-antipyrine and the dichloro-hydroxy-benzene sulphonate in reduced forms are oxidised by the hydrogen peroxide producing a shade of orange color with an intensity proportional to the glucose concentration.

Indications:

Blood glucose test for use with the Glucometer II, Glucometer II with memory or Glucometer M blood glucose meter, or for visual use.

Contraindications

Precautions

As with all laboratory tests, definitive diagnostic or therapeutic decisions should not be based on any single result or method. Any modification of treatment based upon using Glucostix test results should only be done after medical consultation. If reagent pads are discoloured prior to use and do not closely match the zero color block on the bottle, the strips have deteriorated and must not be used.

Limitations of the procedure

Glucostix Reagent Strips should not be used with neonatal blood specimens. This is true for both visual and instrumental use. Glucostix Reagent Strips are not designed for use with serum or plasma. Glucostix results should only be compared with the results of other whole blood methods and be done simultaneously using a portion of the same sample. Glucostix Reagent Strips cannot be used with blood specimens preserved with fluoride. Glucose values in specimens with highly elevated cholesterol and/or triglyceride levels should be interpreted with caution. Extremes in haematocrit can affect Glucostix test results.

High haematocrits (above 50%) tends to cause low Glucostix results. Low heamatocrits (below 35%) tends to cause high results. Extremes in operating temperatures can affect Glucostix instrumental test results. High operating temperatures (above 30&C) may cause high results, low operating temperatures (below 18&C) may cause low results.

Ascorbic acid levels in blood of 0.17\mmol/L or greater will lower Glucostix test results. Elevated levels of uric acid (0.47\mmol/L or greater) in blood will also lower glucose values obtained with Glucostix.

Directions for Use

The directions given must be followed exactly. Accurate and reliable results depend upon strict observance of the test procedures for visual or instrument-based use, that are found in the Glucostix product insert.

When used visually, and after the specified timing period, the test pads must be compared to the color chart on the bottle label. The larger green pad (lower range) measures blood glucose levels from 1 to 6\mmol/L (20 to 110\mg/dL). The smaller orange pad (higher range) measures blood glucose levels from 8 to 44\mmol/L (140 to 800\mg/dL).

The timing of the test varies depending on whether it is visually or instrumentally read. Each of these are explained in detail in the procedure section of the product insert. During the specified timing periods, the glucose in the blood reacts with the reagents in the test pads causing one or both to change color. The greater the amount of glucose, the darker the pads become and the higher the result.

Procedure

Always put a large drop of blood on the test pads so the blood completely covers both yellow pads. When using Glucostix test strips visually or instrumentally, be sure to time exactly 30 seconds from the moment the blood is put on the test pads to the time they are blotted. For visual use only, time 90 more seconds from the moment the test pads are blotted to the time the strip is read. For instrument use, the timing is automatically performed by the instrument. Whether using the visual or the instrument method to read Glucostix test strips, the blotting procedure is identical. Read the blotting instructions in the product insert carefully before attempting to blot a Glucostix Reagent Strip. To develop consistency, apply the blood sample, time the reaction, blot the test pads and read the test results in a similar manner for every test.

Check the performance of the whole system including test strips, technique (sample size, timing, blotting and reading results) and, if appropriate, the instrument, by performing a Gluco System

Testing Of Quality

Normal Control test:

The Gluco System Normal Control package insert gives the control test directions and lists the ranges for acceptable results. Acceptable performance is assured only when the control test result falls within the range specified in the Gluco System Normal Control package insert.

Pack: Strips: 25's, 50's.

Storage and Handling:

Store the bottle in a cool, dry place below 30&C. Do not refrigerate unreacted reagent strips. Do not touch the test pads of the reagent strip. Do not remove the dessicant from the bottle. Keep unused reagent strips in the original bottle with the cap tightly closed. Always replace the cap immediately and tightly after removing a strip. Never transfer reagent strips to another bottle.

Never use reagent strips past the unopened expiration date printed on the bottle label. Use within six months after first opening of the bottle.

Sufficient blood to perform the test may be obtained from the fingertip or ear lobe. A fresh venous whole blood sample may also be used but must be analyzed within 30 minutes after drawing blood. Glucostix reagent strips are not intended for use with serum or plasma. Blood glucose begins to degrade very rapidly after the drawingof blood.

Refrigeration of the sample can delay degradation but not prevent it. The sample must be restored to room temperature before testing.

Common anticoagulants (oxalate, citrate, heparin and EDTA) may be used but fluoride preservatives must be avoided. Samples with haematocrits in the range of 35% to 50% may be used with Glucostix reagent strips (see limitations of procedure).