Policy/Principle: | Clinical Significance: | Certification: | Specimen: | Materials: | Reagents: | Standardization: | Procedure: | Limitations: | Results Derivation: | Expected Results | Quality Control | Maintenance: | References:
The CoaguChek XS System Protime/INR test is CMS “Waived” status, obviating Equivalent QC and Calibration Verification as stated in CLIA regulations. This test is performed as a definitive function to monitor warfarinized patients’ Protime/INR. Results of the test could trigger therapeutic interaction without reflex laboratory analysis.
The CoaguChek XS System test strip contains human recombinant thromboplastin, stabilizers, preservatives and additives. When whole blood is applied to the test strip, the CoaguChek XS meter provides an electrochemical measurement of prothrombin time following activation of blood coagulation with human recombinant thromboplastin. Specimen integrity will be critical. Therefore, formal certification in capillary puncture is required.
The prothrombin time (PT) identifies bleeding disorders dependent on liver production (with vitamin K) of certain clotting factors. Prolonged results are most commonly seen with anticoagulant (Coumadin) therapy and liver failure. Heparin therapy and DIC are other causes of a prolonged prothrombin time.
The INR (International Normalized Ratio) is the ratio of the patients’ Protime to the method-specific population Protime mean offset (via ISI; i.e., International Sensitivity Index) to match, theoretically, the thromboplastin activity of the WHO’S IRP (World Health Organization’s International Reference Preparation). It is a Protime reporting format which should provide a standardized scale for monitoring warfarinized patients and allow effective transferability of Protime results between disparate laboratories and methods.
1. Orientation, authorization and competency of staff and licensed practitioners performing POCT are provided by the director’s (named on the CLIA certificate) designee as indicated in the “Point of Care (POCT) Program” procedure.
2. Protime testing will be performed by specifically certified staff.
A. Certification requires completion of the CoaguChek XS Whole Blood Protime Testing in-service.
B. Operators must be certified in capillary puncture.
C. If the individual seeking certification is unable to demonstrate acceptable capillary puncture technique he/she must be retrained and successfully retested for authorization to perform Protime/INR testing.
D. If the individual seeking certification is unable to demonstrate acceptable performance of quality control, he/she must be retrained and successfully re-tested for authorization to perform Protime/INR testing.
E. Re-certification is required annually:
a. Re-certification for an individual may be required more often if deemed necessary. When an instructor observes improper technique, he/she may decertify the operator immediately. Arrangements for re-certification of that individual must be made through their immediate supervisor.
b. Re-certification requires an operator to successfully complete the CoaguChek XS Whole Blood Protime/INR Testing Self-Instructional Competency documentation packet.
F. Certification Records:
a. The certification record of operators and instructors will be maintained in the Retail Pharmacy site performing the testing.
b. The certification record of Medical Associates operators and instructors will be maintained in the Laboratory at Medical Associates
1. Specimen Requirements: Capillary whole blood is typically the specimen of choice, however, venous whole blood obtained by syringe may also be used. Capillary whole blood may be used by applying sample directly to the test strip.
Notes: It is absolutely essential that the capillary puncture for coagulation testing produce a free-flowing, hanging drop of blood. Anything short of this will simply not generate reliable results! If the puncture does not produce a free flowing, hanging drop of blood, THE TEST MUST NOT BE RUN. Sample integrity problems can often be prevented if a warm washcloth is used to enhance capillary bed circulation in the patient’s hand for just a minute or two prior to the procedure.
2. Specimen Collection:
A. Assemble the necessary equipment:
a. Lancet device
b. Cotton ball or gauze pad
c. Alcohol wipe
d. Fresh, non-sterile gloves; changed for each patient encounter.
B. Capillary Puncture using a lancet device:
a. If using the Capillary Blood Collection System, prepare capillary collection device by firmly inserting the capillary tube into the capillary bulb. Set aside until needed.
b. For fingersticks, when possible, patients will wash their hands in warm soapy water, rinse, and dry completely.
c. For fingersticks, place the patient’s hand in a dependent position. If the patient’s fingers are cold, wrap a warm washcloth around the fingers for several minutes prior to performing the puncture.
Cleanse the puncture site with an alcohol pad just prior to the procedure; allow the site to air dry. The area is then “milked” very gently to encourage capillary flow.
d. Twist off the protective disc from the lancet device.
e. Position the lancet on the puncture site. On fingers and toes, for a “normal” puncture depth, place the oval opening “across” the long axis of the digit. For a “deeper” puncture, position the oval opening “with” the long axis of the digit.
f. While applying a small amount of pressure on the lancet device against the puncture site, press the trigger.
g. Gently milk the area to produce a large hanging drop of blood. Do not “squeeze” the tissue around the puncture site.
h. The first drop of blood is used for testing on the CoaguChek XS System. DO NOT wipe the first drop of blood.
i. When testing is complete, discard the lancet device. Lancets are not to be reused, even on the same patient.
j. Rotate puncture sites on each patient to minimize soreness.
1. CoaguChek XS Monitor
2. Laboratory-approved Lancet device
CoaguChek XS PT Test Strip (Roche Diagnostics #04625315160)
1. Store strips at room temperature (2 - 30°C). Strips are stable until expiration date on the label.
2. A new test strip code chip is included with each test kit. Each code chip is specific to that lot of test strips. Use this code chip only with tests in that test kit. The numbers on the code chip must match the last three numbers on the test strip pouches in each kit. The code chip should not be exposed to moisture or devices that produce magnetic fields.
Each lot of test strips is calibrated to a reference lot that is traceable to the WHO International Reference Preparations using a code chip specific for the lot number.
1. Turn the meter off before inserting or removing Test Code Chip. Failure to do so may result in a CODE ERROR message.
2. Insert the code chip (with the code number facing up) into the chip slot until it snaps into place. The 3-number code on the test strip container must match the 3-number code on the code chip.
Note: Each box of test strips comes with a matching code chip. Every time a new box of test strips is opened, the code chip must be replaced.
3. Turn the meter on.
4. Take the test strip out of the container and insert the strip into the meter with the arrows pointing into the strip slot.
Note: The sample must be applied to the strip within 10 minutes of taking the strip from the container.
5. Apply a large hanging drop of blood directly onto the target area of the test strip, either from the side or the top. The monitor will beep as it detects the drop.
6. The result will appear in the display screen in about one minute.
1. The CoaguChek test measures Protime/INR results in persons on warfarin-type (Coumadin) therapy. It should not be used to screen patients for normal Protime nor should it be used to monitor persons on heparin therapy.
2. The presence of anti-phospholipid antibodies (APAs) such as Lupus antibodies (LA) can potentially lead to prolonged clotting times, i.e., elevated INR values. A comparison to an APA-insensitive laboratory method is recommended if the presence of APAs is known or suspected.
1. INR results will be displayed on the monitor screen. INR is calculated by the analyzer using a fixed normal population mean of 12.0 and reagent ISI of 1.0.
2. Results are documented on the patient’s chart.
3. The INR analytical range is 0.8 to 8.0. If the INR result is < 0.8 or > 8.0 the result must be confirmed by the laboratory analysis. Report the result with the comment “PT/INR should be re-ordered for Laboratory confirmation.”
4. In rare cases, patients with long clotting times (>8 INR) may receive an “ERROR 7” message on the meter display. If this error message appears again when the test is repeated, the result must be checked using another method.
5. If an up or down arrow is displayed the test result is outside the measuring range for that particular lot of test strips. When an Error Code is displayed, the test could not be measured.
6. If there is a questionable result, i.e. too high, critical or too low notify the patient’s physician immediately. Document on the CoaguChek log that the result was called to the physician along with initials of the person to whom the result was reported.
7. To retrieve the patient results:
A. Ensure instrument is turned on.
B. Wait for the flashing test strip icon to appear.
C. Press the Mem button. Use the Mem button to scroll through the monitors memory. Results are displayed with the date and time the test was performed.
1. Target INR Ranges (set by physician)
A. 2.0 - 3.0
B. Mechanical Valve: 2.5 - 3.5
≥ 5.0 for orally anticoagulated patients
The CoaguChek XS System has quality control functions integrated into the meter and test strips, so liquid controls are not required. The meter automatically runs a quality control test as part of every blood test. If the quality control fails, the meter displays an error message.
1. Turn the instrument off.
2. Using a lint-free tissue, lightly dampened with isopropyl alcohol, gently wipe off the exterior of the instrument. DO NOT use sprays of any sort.
3. Ensure that the blue test strip guide cover remains tightly closed while cleaning the housing. Make sure that no liquid enters the meter or accumulates near any opening.
4. Wipe away residual moisture and fluids after cleaning the housing.
5. Allow wiped areas to dry for at least 15 minutes before performing a test.
6. Hold the meter upright with the test strip guide facing down.
7. Using a cotton-tipped swab lightly dampened with alcohol; wipe off the test guide strip and the underside of the door. Ensure the swab is only damp, not wet.
8. Dry the test guide strip and underside of the door with a dry, cotton-tipped swab.
9. Let the inside of the test strip guide dry for at least 15 minutes before re-attaching the test strip guide cover and start testing again.
10. Maintenance is documented on the CoaguChek XS log sheet.
1. CoaguChek XS System User’s Manual; Roche Diagnostics, 2006.
2. CoaguChek Test Strip package insert. Roche Diagnostics; Indianapolis, IN. 2007.
3. Urgent Medical Device Correction. Roche Diagnostics Corporation. Indianapolis, IN. 7/22/09
i. May 2008 M. Muir, L. McGovern
ii. August 2009 L. McGovern (Revised: XIII., XIV.3.)
iii. October 2009 L. McGovern, S. Raymond (Revised: III.1. added)
Representative: Mercy Family Pharmacy
January 2011 L. McGovern (Revised: IX.2.)
May 2012 S. Jaeger (no changes)