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REDUCING SUBSTANCES USING CLINITESTŪREAGENT TABLETS

 

 

 

PRINCIPLE                            CLINITESTŪ Reagent Tablets are based on the classic Benedict’s copper reduction reaction, combining reactive ingredients with an integral heat generating system.  
Copper sulfate in CLINITEST reacts with reducing substances in urine, converting cupric sulfate to cuprous oxide.  The resultant color, which varies with the amount of reducing substance present, ranges from blue through green to orange.  Heat required is furnished by the reaction of sodium hydroxide with water and with citric acid.  Sodium carbonate and citric acid help to dissolve the tablet.

 

CLINICAL UTILITY                The Chemstrip glucose pad is only specific for the detection of increased levels of glucose and will not detect increased levels of other reducing substances (galactose, fructose, lactose, and pentose).  A copper reduction test like the CLINITEST detects some hereditary disorders, which may be present in pediatric patients.

 

SPECIMEN                            12 ml fresh urine with no preservatives
Refrigerate urine if testing cannot be done immediately

 

INTERFERENCES                A number of substances found in urine, such as salicylates and penicillin, react positively with CLINITEST Reagent Tablets but are not present in most cases in sufficient quantity to interfere with the test.  Ascorbic acid, nalidixic acid, cephalosporins and probenecid in large quantities may cause false positive results. 

 

NORMAL RANGE                  Negative  (Blue color)

 

REPORTING LIMITS            Urine containing more than 2% sugar using the 5-drop method may cause a very rapid color change during the boiling and 15-second waiting period.  OBSERVE the solution closely during this time to detect “pass-through” color changes.  Should these occur, the color will pass rapidly through bright orange to a dark brown or greenish brown.  In this case, record the result as “greater than 2%” sugar. 
Low specific gravity urines containing glucose may give slightly elevated results.
High protein concentrations extend the boiling time, increase foaming and may make visual comparison difficult.
The presence of X-ray Contrast Media (Hypaque meglumine) in urine affects CLINITEST Reagent Tablets producing reduced glucose results (false-negatives).

 


 

COMPUTER CODES            N/A

 

 

QUALITY CONTROL            Pathology performs quality control check using Alta Positive and Negative Controls whenever a container is first opened to confirm the performance of the reagent tablets.  Do not report any patient results when quality control results do not match Quality Control criteria.  Repeat test and discard tablets that do not meet quality control standards.

 

CALIBRATION                       N/A

 

PROCEDURE                        1.   With dropper in upright position, place 5 drops of urine in a test tube.
2.   Rinse dropper with water and add 10 drops of water to test tube.
3.   Drop one Clinitest tablet into test tube.  Watch while complete boiling reaction takes place.  Do not shake test tube during boiling, or for the following 15 seconds after boiling has stopped.
4.   At the end of this 15-second waiting period, shake test tube gently to mix contents. Compare color of liquid to Color Chart provided on the package insert.  Ignore sediment that may form in the bottom of the test tube.  Ignore changes after the 15-second waiting period.
5.   Record the percent (%) result which appears on the color block that most closely matches the color of the liquid.

 

 

CALCULATIONS                   N/A

 

REPORTING                         Record the percent (%) results which appears on the color chart that most closely matches the color of the liquid  after 15-second waiting period.
NOTE:  CLINITEST is not specific for glucose and will react with sufficient quantities of any reducing substance in the urine.  Failure to observe the reaction at all times can lead to erroneously low results if the “pass-through” phenomenon is missed.

 

 

REAGENTS                           CLINITESTŪ Reagent Tablets (100 tablets Product No. 2126)

1.   Contains 1 part copper sulfate, 12 parts sodium hydroxide, 4 parts sodium carbonate, 15 parts citric acid, filler and binder.
2.   Prolonged stability in the UNOPENED container, either in the glass bottle or foil-wrapped, if stored at room temperature (59-86oF or 15-30oC).
3.   Once the bottle is opened, stability is STRONGLY dependent on protection from moisture.  Tablets should be used on a regular basis and not stored for extended periods of time after the bottle is opened.
4.   PROTECT CLINITEST TABLETS FROM LIGHT, HEAT AND MOISTURE.  Moisture causes CLINITEST tablets to turn a deeper shade of blue.  If tablets darken, or if test results seem questionable or inconsistent

 

 


with expected findings:  1) Confirm that product is within expiration date shown on label or foil; 2) Check performance with a positive control. If proper result is not obtained, discard and retest with fresh CLINITEST Reagent Tablets. 
NOTE:  Contains poison; causes severe burns
Warnings:  Contains sodium hydroxide (caustic soda).  Avoid contact with skin, eyes, mucous membranes and clothing.  CLINITEST tablets are highly sensitive to moisture from air or water.  Excessive moisture may cause a chemical reaction and a bottle explosion may occur. 



 

REFERENCES                      Product insert, CLINITESTŪ Reagent Tablets, Bayer Corporation,

                                                Elkhart, IN, 9/95.





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