procedure for inr testing using the coaguchek xs …

BHR HOSPITALS – POCT

PROCEDURE FOR INR TESTING USING THE COAGUCHEK XS

PLUS SYSTEM

Q Pulse record: Pathology 893 Revision: 2 of 12

Approved / Authorised by: S Sadan

Paper copy number, when printed:

1.0 PURPOSE / CLINICAL RELEVANCE

The CoaguChek XS system from Roche Diagnostics is a point-of-

care anticoagulation monitoring device that measures a patients

INR clotting time. Performing PT/INR testing at the point of care

rather than at an outside lab allows healthcare professionals to

make dosage adjustments and talk with patients immediately, to

help protect them from potentially serious complications which

offers several benefits over laboratory testing. The coaguchek XS

system uses fresh capillary or non-anticoagulated venous blood.

Staff should be aware that the INR must only be used for

monitoring vitamin K antagonist (VKA) therapy. The INR is not

suitable test for the monitoring of other anticoagulants or the

diagnosis of bleeding disorders.

The aim of this document is to describe the procedure for using

the CoaguChek XS Plus INR meter, including any limitations of

such procedures. This document should be read in conjunction

with the CoaguChek XS Plus Operator’s Manual supplied with the

instrument together with relevant BHRUT Policies.

2.0 RESPONSIBILITY

2.1 Divisional Director, Clinical Support

Has responsibility for ensuring POC investigation procedures, outside the laboratory,

have clearly defined procedural guidance and that the Trust provides/supports the

training required for staff to undertake POCT safely.

2.2 Clinical Leads

The responsibility for patient results obtained by POCT processes lies with the

appropriate Clinical Lead for the ward or department. Any therapeutic decision based

on a POCT result is also the responsibility of the Clinical Lead. The Clinical Lead

must decide for which patient groups the POCT process is appropriate and provide

guidelines for interpretation of results and further patient management. These

guidelines should include when it is necessary to compare a result with a laboratory

processed sample. It should also detail the back up service available in the event of

failure of POCT devices or processes.

2.3 Heads of Nursing and Matrons

Heads of Nursing/Midwifery and Matrons have a responsibility to ensure correct

procedures are followed at all times.



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2.4 Ward or Departmental Managers

The Manager must ensure that all users within the department understand the concept

of POCT and have been trained and assessed as competent to use the POCT device or

process correctly, safely and in accordance with the manufacturer’s recommendations

and Trust policy.

2.5 All Users

Individual users are responsible for the correct use of these machines as specified

within this document and associated BHRUT Polices/procedures. All members of

staff are responsible for their own safety and for ensuring their POC training is

updated and that their competence is maintained.

This standard operating procedure is relevant to all healthcare staff throughout BHR

University (NHS) Trust who are required to perform a POCT INR using the Roche

Coaguchek XS Plus system.

2.6 Pathology

The Haematology/POCT department(s) will be responsible for ensuring this

document is correct and fit for purpose and for monitoring EQA returns and advising

on issues of poor performance.

3.0 REFERENCES

No. Title: Pathology Q-Pulse

Document No. :

Trust Ref:

1 Clinical Pathology Accreditation (UK) Ltd.

Standards for the Medical Laboratory v2.1, Mar

2009

628

2 POCT QA & Audit Framework 2101

3 Additional Standards for POCT facilities v1.0, Apr

2010

2164

4 Point of Care Testing Policy. 2107 2010/DG/15 v2

5 The Retention and Storage of Pathological Records

and Specimens (4th

Ed., 2009) Royal College of

Pathologists Guidelines

141

6 Infection Prevention & Control Policy 2010/IC/04 v1.1

7 Policy & Guidelines for Safe Handling & disposal

of Sharps

See Intranet

8 Policy for Single Use, Single Patient Use and

Limited Use Medical devices

2009/PC/36

v1.0

9 Incident and Serious Untoward Incident (SUI)

Reporting Policy

2009/CG/45

Individuals who have not been trained and who have not completed their

competency in the use of this device are not authorized to use this procedure!



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10 Policy and Procedure for the Safe Use of Medical

Devices

2009/MD/57 v2

11 Patient Identification Policy 2009/PC/37 v2

12 Risk Management strategy & policy 2009/CG/43 v3

13 Disposal Policy for Clinical & Non-Clinical

Equipment & Furniture

2003/68/BHR/D

is.Equip.

14 COSHH Policy 2009/CG/41 v3

15 Management of Waste Policy 2009/CG/11

16 Roche CoaguChek XS Plus User manual 895

17 Performance comparability study of the Roche

CoaguChek INR meter against the laboratory

CA7000 method

1210

4.0 DEFINITIONS

Acronym Definition

BHRUT Barking, Havering and Redbridge University Hospital (NHS) Trust

POC(T) Point of Care (Testing)- At or near the site of the patient, the use of Medical

Devices outside of the traditional laboratory setting for the testing of patient

samples

User Any person who handles a POCT instrument to produce patient results, carry out

maintenance or performs QA checks. This includes Clinicians, Nursing Staff,

Healthcare Scientists and Service Engineers.

SOP Standard Operating Procedure. This is the gold standard protocol that specifies

how, when and by whom the instrument can and should be used.

QA Quality Assurance is the sum of the processes or systems that ensure the

instrument is fit for purpose and the results produced are correct and reliable for

the safety of the patient and users

IQC Internal Quality Control. This is a means of determining that the POCT instrument

is technically performing correctly at that specific time.

EQA External Quality Assurance. This is a means of determining how a particular

POCT instrument is performing in comparison to other instruments elsewhere

NEQAS National External Quality Assessment Scheme. This is an EQAS provider within

the UK.

RA Risk Assessment. This is a process for identifying the potential risks associated

with the operation of an instrument and the effectiveness of controls to mitigate

these.

INR International Normalised Ratio

PT Protrombin time

VKA Vitamin K antagonist

COSHH Care of Substances Hazardous to Health. This is a special form of risk assessment

applied to hazardous chemicals and substances that may be present or required for

use with the instrument.



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5.0 DOCUMENTATION

No. Title: Pathology Ref: Trust Ref:

18 POCT Training Framework & Competency

Assessment for Roche Coaguchek XS Plus

3401

19 Non-audit non-compliance note/clearance form 983

20 POCT Device User Training & Competency Policy 2119

6.0 ACTIONS AND METHODS

6.1 Health and Safety / COSHH / Risk Assessment

All samples should be considered potentially infectious and care should always be

taken when handling human specimens and other material prepared from human

origin. Even if these samples are tested for infectious agents and found non-reactive,

no method can offer complete assurance that HIV, Hepatitis B Virus or other

infectious agents are absent.

Personal protective equipment should be worn in accordance with recognized safety

procedures when handling samples, control material, equipment and other kit

components as specified within this document and Trust Policy & Procedure6, 7,

8,10,12,15.

Waste must be disposed of in accordance with Trust Policy & Procedure15

POCT users must be able to demonstrate that QA standards are being met and all

risks associated with the use of the device are minimized. A local Risk Assessment

for use of this device should be performed and held on file by the respective clinical

area in accordance with Trust Policy & Procedure10, 12

.

This procedure does not use any hazardous chemical components/reagents and is

therefore exempt from COSHH14

.

6.2 Principle of examination

The CoaguChek XS Plus performs an electrochemical measurement of prothrombin

time (PT) using a recombinant human thromboplastin reagent and a peptide

substrate, which measures thrombin. Application of sample leads to activation of

coagulation by the thromboplastin and results in thrombin generation. Thrombin

cleaves the substrate into a residual peptide and electrochemically active

phenylenediamine thereby generating an electrochemical signal. The time elapsed

from addition of sample to signal generation is used to calculate the INR value.

6.2 Personnel to do the task / level of training required

Use of this device is ONLY permitted by staff who have completed the

Coaguchek XS Plus training framework & hold a valid competency

assessment1,2,3,4,8,18

. YOU MUST NOT USE THIS DEVICE UNLESS YOU

ARE COMPETENT TO DO SO. UNAUTHORISED USE MAY RESULT IN

ACTION BEING TAKEN AGAINST YOU!



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6.4 Specimen requirements and means of identification

Patient identification must conform to Trust Policy11

.

An 8 µL sample of whole blood is required. A single drop (about the size of a

ladybird) of whole capillary blood obtained from a finger using a suitable lancet

device is sufficient. Alternatively, whole venous non-anticoagulated blood may be

applied directly to the test strip from a syringe.

6.5 Method / Procedure

Prior to testing, the operator should ensure that batteries and the correct code chip

are inserted. By pressing the set button the user can modify settings for dates,

times, display units, alarm or beep tone and alter settings for INR target ranges.

The current date and time should be set and the correct coagulation units selected

(i.e., INR) before testing.

Refer to the Roche CoaguChek XS Plus User manual for full instructions.

Pre-testing Checks

Ensure that the number on the code chip matches the number on the label of the test

strip container. The CoaguChek XS Pus system will not proceed to measure unless

the PT XS test strips used have been calibrated on the monitor. The monitor will

store up to 60 lot numbers of test strips. Once the code chip has been inserted for a

particular batch of PT XS code strips the monitor will remember this mitigating the

need for the operator to change code chips each time different PT XS test strips are

used when changing over batches. The test strips must be within the manufacturer’s

expiry date for testing.

PT XS test strips can be kept at room temperature but must be used within 10

minutes following removal from container.

Internal quality control

Each PT XS test strip contains a built in control that runs in parallel with the test

sample. Once the drop of blood is applied to the test strip an hourglass symbol

appears on the display to indicate the test has begun. If the in built QC check is

successful a tick will appear in the QC box on the display. If the control fails, repeat

the test with another XS test strip. If the repeat also fails contact the manufacturer or

the haematology department for advice (see section 6.16 for contact details). Isolate

and do not use the device.

A liquid quality control is also available which should be run daily on each meter in

high use areas or weekly where the meter is used only frequently. If in doubt consult

the POCT Coordinator for advice. Record all IQC within the Quality Control Record

Book.



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To run the liquid quality control:

i. Load in the QC code chip, if this is the first time that this batch of control

has been used.

ii. Open the lid of the PT control vial and remove the rubber cap.

iii. Hold the pipette with the sealed pipette neck pointing upwards and cut off

the end with scissors.

iv. Transfer the entire contents of the pipette into the vial, making sure that the

pipette does not come into contact with the dried control plasma.

v. Close the container and swirl the vial using a circular motion to dissolve all

of the dried control plasma. Do not shake the vial or turn it on its side.

vi. The reconstituted control is ready for use one minute after the addition of

the diluent and must be used within 30 minutes of reconstitution.

vii. Switch on the monitor and press the QC TEST button.

viii. When the test strip icon is displayed, remove a test strip from the container.

Ensure that the number on the code chip matches the number on the

container. Close the container immediately.

ix. Insert the test strip with the “CoaguChek XS PT” lettering facing upward.

x. Select the appropriate QC code or select NEW CODE if you are using a new

batch of PT Control. If using a new lot of PT control you will need to insert

the QC code chip

xi. The hourglass icon shows that the test strip is warming up. When the

warming process is complete, a beep tone indicates that the monitor is ready

to test. At the same time a 120 second countdown begins. You must apply

the control solution to the test strip within this time.

xii. Using the pipette draw up the dissolved contents of the vial and apply a

hanging drop to the sample application area of the test strip.

xiii. Record the result displayed on the screen in the Quality Control Record

Book.

xiv. If the control is out of range, repeat the QC test. If the repeat is out of range,

perform the QC again using a fresh vial of PT Control.

xv. If the control is still out of range contact the manufacturer or the

haematology department for advice. Isolate and do not use the monitor.

Testing Procedure

i. Place the monitor on a level vibration-free surface or hold it so it is roughly

horizontal.

ii. Switch on the monitor and wait until the menu is displayed.



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iii. Touch the PATIENT TEST BUTTON on the screen. If QC BLOCK is

displayed instead of the patient test button, you must run an internal QC

before you can perform a test.

iv. Enter the patient’s hospital number or name using the alphanumeric keys.

v. When the test strip icon is displayed, remove a test strip from the container.

Ensure that the number on the code chip matches the number on the

container. Close the container immediately.

vi. Insert the test strip with the “CoaguChek XS PT” lettering facing upward.

vii. The hourglass icon shows that the test strip is warming up. When the

warming process is complete, a beep tone indicates that the monitor is ready

to test. At the same time a 120 second countdown begins. You must apply

the drop of blood to the test strip within this time.

viii. Lance the fingertip and apply the first drop of blood to the application area

of the test strip. Apply the blood within 15 seconds of lancing the fingertip.

ix. The result will be displayed on the screen within two minutes. Record this

result on the result record sheet, the patient’s notes and the patient’s yellow

record book, (if available).

After Testing

Remove the test strip from the monitor and dispose used test strip and lancet in a

clinical waste container.

Important notes

Always …

• Close the container immediately after having removed a test strip.

• Operate the meter at an ambient temperature between 59°F and 90°F (15°C

and 32°C).

• Place the meter on a level, stable surface (table) or hold it so it is roughly

horizontal.

• Follow the information on correct handling of test strips in the package insert.

• Keep the test strip guide and housing clean.

Never …

• Store the meter at extreme temperatures (greater than 104°F or 40°C).

• Store the meter in damp or humid conditions without protection.

• Remove or insert the code chip while the meter is performing a test.

• Use the code chip from a pack other than the one in use.

• Touch or remove the test strip during a test.

• Wait more than 15 seconds after lancing the fingertip before applying the

blood.

• Add more blood after the test has begun.

• Perform a test with a drop of blood from a previous puncture.



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6.6 Equipment and special supplies

The CoaguChek XS Plus system comprising:

• A CoaguChek XS Plus monitor.

• A power supply unit or 4 x 1.5V AA batteries or rechargeable battery pack

• Test strips (CoaguChek XS PT test strips) stored at 4-32°C, store in original

container with cap closed. Must not be used after expiry date. Once removed

from the container use within 10 minutes.

• A batch specific Code chip – test strip used to calibrate the meter to the lot

number of the test strips (a new code strip comes with each box of test strips)

• Internal quality Control (CoaguChek XS PT control solution) – reconstituted

freshly as required (Store a 2-8°C prior to use)

• Lancets (Accu-Chek Safe-T-Pro Plus, Roche Diagnostics)

• Quality control record book (supplied by Roche)

• Patient result record sheet.

All consumables are ordered from Roche Diagnostics directly.

6.7 Reagents, standard or calibrants and internal control materials

PT XS test strips (Ref: 04625315160)

Control material

6.8 Calibration

The code chip, supplied with each box of test

strips, provides the monitor with lot-specific

calibration data and expiry date. Whenever a new

box of test strips is opened the code chip should be

placed in the code chip slot. Although the code-

chip may be removed, e.g., when a QC code chip is

inserted, it is best to leave the code chip in the

monitor.

The code chip should be inserted when the

meter is off

6.9 Internal quality control procedures & criteria against which examination

processes (measurement & observation are judged)

The CoaguChek XS Plus System has a number of built-in quality-control functions.



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• A check of the electronic components and functions every time the meter is

turned on.

• A check of the test strip temperature while a test is in progress.

• A check of the expiration date and lot information on the test strip carried out by

the code chip.

• A two-level, on-board quality control test and patient result determination within

a single test chamber.

External Quality Assessment (EQA)

EQA is mandatory and involves analysis of samples issued by external agencies.

The results of which are collated and compared to results from similar test sites and

reported back to users. This allows for an independent, but retrospective, evaluation

of performance.

The EQA scheme for the CoaguChek XS Plus is run by UK NEQAS for blood

coagulation ([email protected]).

It is the responsibility of each department to register with UK NEQAS.

The EQA samples must be processed as per the written instructions supplied by UK

NEQAS.

A copy of all EQA results should be made available to haematology and filed for

reference in accordance with the Royal College of Pathologists Guidelines5.

In the event of failure (results out of consensus), the relevant department together

with haematology and the POCT co-ordinator shall perform a full review including

root cause analysis to identify the reason(s) for the failure. This will include

identifying if the problem lies with an instrument fault, poorly defined procedures

or with users of the instrument failing to adhere to protocols.

Three consecutive failures in NEQAS survey will eventually lead to the site

being identified as a persistent poor performer. This will result in statutory

regulatory bodies initiating dialogue with the users to try to identify why this

problem is occurring. Ultimately, this may lead to a recommendation by the

statutory body that the service must cease being provided due to unsafe

practices.

Internal quality control (IQC)

It is good practice to run an IQC test as part of a daily routine equipment check if

the monitor is in daily use, or weekly as a minimum if the monitor is used less

frequently.

DO NOT USE THE METER IF THE IQC IS OUT OF RANGE



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6.10.1 Limitations of the examination, including interferences, cross reactions and

reportable intervals

All POCT devices have limitations and this should be remembered at all times. If

an unexpected result is obtained or a result is not consistent with the clinical picture

a repeat sample should be tested and/or a sample referred to the laboratory.

Users should note the following:

� The blood drop must be a minimum of 8 µL in volume

� Patients with haematocrit ranges between 25% and 55% can be tested using this

machine. Patients with haematocrit levels outside of this range should not be tested

using this monitor.

� The CoaguChek XS Plus is unaffected by bilirubin levels of up to 513 µmol/L, and

triglycerides levels of up to 5.7 mmol/L

� Antiphospholipid antibodies may falsely prolong coagulation times.

� The CoaguChek XS Plus must not be used in patients receiving anticoagulants

other than vitamin K antagonists (alone or in combination with VKA, e.g.

Unfractionated or LMH heparin, hirudin, fondaparinux, etc.)

� The CoaguChek XS Plus must not be used for samples with haemolysis greater

than 0.31 µmol/L

� Do not use the meter near strong electromagnetic fields which could interfere with

the proper operation of the device

Please refer to the strip package insert for full details of interfering substances. If

in doubt, send a sample to the laboratory.

6.11 Recording and calculation of results

6.12 Reporting reference limits

The monitor displays the result as an INR

6.13 Alert / critical values, where appropriate

Device measuring range INR 0.8 – 8.0

Warfarin has a narrow therapeutic window and its required intensity of action will

vary for different clinical indications and patients. Refer to departmental

policy/protocol for acceptable INR ranges.

All patients’ results must be recorded within the patient’s medical record,

notes and/or treatment/observation chart, together with the ID or name of the

operator and date/time to allow for full audit trail. It must also be stipulated

that this result was obtained by POCT and be distinguishable from results

obtained from the central laboratory3.



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Note:

Unexpected or new INR values greater than 6.0 should be referred to the central

laboratory for confirmation17

.

6.14 Responsibilities of personnel in authorising, reporting and monitoring reports

All users are responsible for the correct and appropriate use of the meter in

accordance with this standard operating procedure and all relevant BHRU Trust

Policies & Procedures.

6.15 Performance criteria

Cleaning/Disinfection Procedures for CoaguChek XS Plus

Failure to follow procedures for cleaning/disinfecting the meter may cause device

malfunction.

DO NOT USE ANY SPRAYS.

Cleaning/disinfecting the housing part of the meter:

1. Ensure that the measurement chamber cover (blue cover) remains tightly closed

whilst cleaning.

2. Do not allow liquid to accumulate near the opening and ensure that no liquid enters

the meter.

3. Use only a damp swab or cloth i.e. not a wet cloth

4. Wipe away residual moisture or fluid using a dry swab or cloth after cleaning

5. After drying the instrument, do not use it for at least 15 minutes to ensure the

housing are is completely dry.

Cleaning/disinfecting the measurement chamber:

1. The only suitable cleaning/disinfecting agents for this procedure are 99%

Isopropanol, 96% Ethanol. Alternatively, a mixture of 1-propanol/2-

propanol/ethanol/water as found in some cleansing alcohol prep tissues may be

used.

2. Using gloves, remove the measurement chamber cover (blue cover).

3. Hold the meter upright with the measurement chamber facing down.

4. Use only a DAMP swab or cloth, apply the cleaning agent for the minimum

recommended contact time (see cleaning agent label/insert).

5. Thoroughly wipe away all residual using a dry swab or cloth.

6. After drying the instrument, allow at least 15 minutes before re-attaching the test

strip guide cover, to ensure it is completely dry before re-commencing testing.

Troubleshooting and Error Messages

Depending on the circumstances, an error message may appear on the display of the

meter. As a first step, try the solution suggested for that error. Should the problem

persists, contact Roche Customer Service and inform the laboratory.



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6.16 Contact Information

Name: Contact details:

POCT Coordinator, Pathology department, King

George Hospital

Ext 8472

0208 970 8472

[email protected]

Haematology Laboratory, Queens Hospital Ext. 3645

Roche Diagnostics Ltd, Charles Avenue Burgess

Hill, West Sussex, RH15 9RY

01444 256000

Roche Customer Services (technical support) 0808 100 8010

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