Pathology Directorate / F Examination Process
F2 Examination procedures
Printed on : 02/08/2010 Page 1 of 4
Blood Sciences
Section : Point of Care
HEMOCUE HAEMOGLOBIN 201 DM
Site/Area of application / Point of Care
Index code / BSF2POC003 v 2
Superseded documents / BSF2POC003 v 1
Implementation date of this version / 30th July 2010
Approver of content of SOP / Uche Okeahialam Author: Rob Coleman
Reason for change / Current SOP template
Keywords for search on EQMS / Poct, HEMOCUE HAEMOGLOBIN Hb .
This document is controlled using the Pathology EQMS software.
Controlled printed copies can be identified by the authorisation signature present in the space below. Upon request further authorised copies can be obtained through the department’s quality system.
Uncontrolled copies may be printed for an individuals use but should not be used after 1 week from the date of printing.
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1. CLinical relevance/purpose of procedure
It has been agreed that this procedure will be used to measure blood Hb levels in certain agreed areas of the Trust. These areas are Maternity Theatres (LGI, and SJUH), Chapel Allerton Theatres, and Moynihan Theatres (D floor, Clarendon Wing). It has also been agreed to allow this procedure to be used in the Cardio- Respiratory Laboratories (Chancellor Wing, SJUH)
2. principle of procedure
The reaction in the microcuvette is a modified azidemethaemoglobin reaction. The erythrocyte membranes are disintegrated by sodium deoxycholate, releasing the haemoglobin. Sodium nitrite converts the haemolglobin iron from the ferrous to the ferric state to form methaemoglobin, which then combines with azide to form azidemethaemoglobin.
The reaction is followed photometrically to an end point condition were the analyser uses a two wavelength measuring method, 570nm and 880nm, for turbidity compensation.
3. personnel / training requirements
Only staff who have official documented training can use the Hemocue analyser. Access to the analyser requires a personal password. This password must not be shared.
4. specimen requirements
Sample types: - Finger prick fresh blood, EDTA (preferred) or heparinised whole blood-Venous, arterial, or capillary samples.
Minimum volume: - 500µL
Samples are known to be stable for: - 7 days at room temperature or 4°C
5. equipment
HemoCue Haemoglobin 201 Data Management Analyser for blood haemoglobin determinations (g/L) complete with operating instructions, a rechargeable battery and UK adaptor/charging system. Catalogue No. 12.11.44
6. health and safety/risk assessment
Provided that Departmental Safety Procedure, protocols, manufacturer's instructions, and good laboratory practice are followed throughout this procedure, the following risk assessment applies:-
Preparation: Low Risk
Instrumental: Low Risk
Chemical: Low Risk.
Sample: High risk. Samples must be treated as contaminated waste and disposed of
accordingly. Used cuvettes are disposed of in yellow sharps bins, and disposed of as clinical waste, in accordance with the clinical waste disposal policy of the ward.
See the COSHH assessment BICOSHH153
7. reagents
HemoCue Haemoglobin 201+ Microcuvettes
Storage conditions and location: - Room temperature adjacent to instrument.
Available in packs of 200 (4 tubs of 50). Catalogue No. 11.17.16.
All reagents are immobilized within the microcuvette.
Sodium Deoxycholate 40%w/v
Sodium Azide 20%w/v
Sodium Nitrite 22%w/v
Non-reactive ingredients
HemoTrol Control Material Low – range 80 ± 4.0g/L
Available in 2 x 1ml vials per box. Catalogue No. 022.001.002
HemoTrol Control Material Normal – range 120 ± 6.0g/L
Available in 2 x 1ml vials per box. Catalogue No. 022.002.002
See the COSHH assessment in the COSHH file.
8. Calibration
The equipment is factory calibrated.
9. quality control
Hemotrol dropper QC Low and Normal Quality Control Solutions. Cat no Catalogue No. 022.001.002. Eurotrol B.V., Keplerlan 20, 6716 BS Ede, the Netherlands
Internal quality control is analysed once daily by the clinical staff.
Quality control material is stored in a fridge within each clinical unit.
There are 2 levels of QC, each of which must be tested within a set 24 hours period. There
is a 2 hour count down before the QC’s will expire. Ideally the QC’s need to be tested
between 7:00 AM and 9:00 AM
Stability once made up/opened: 30 days
If the QCs are not tested after 24 hours, patient tests will be blocked until the QC’s have been tested.
Internal Quality Control (QC) material analysed results are stored within the analyser
and transferred back to management program after docking. Both QC levels must be tested.
Any results not complying with limits will be flagged, and action will be taken to find the cause,
and take corrective action.
External Quality Assessment participation:-
WEQAS
Two samples are distributed by Clinical Biochemistry at bimonthly intervals.
The samples are analysed on receipt and results entered on interactive WEQAS website.
10. computer / telepath codes
N/A
11. procedure or methodology
The HemoCue DM 201 is only operational by staff with active barcodes.
Press the [ON] button and pull out the cuvette holder.
The following message will appear “please pull out the cuvette holder”. Moving the cuvette holder into the open position initiates the optical self-check, once complete the main menu will appear.
Press the scan button on the screen and scan in operator barcode.
Press the cuvette symbol for a patient test.
Scan or type using [ 123 ] button the lot number of the cuvettes.
Enter PID (patient identification number) in full.
Verify cuvette batch number and PID – press [OK]
Completely fill the microcuvette with blood (approximately 10 µL), wipe away excess blood from the cuvette with a clean tissue.
Place the filled cuvette into the cuvette holder and push the tray into the measuring position.
After 15-60 seconds the haemoglobin value is displayed.
Press [OK] to accept the results and dispose of cuvette (sharp safe plastic container).
For unsatisfactory results select sample verification, the double cuvette symbol.
VERIFICATION
A duplicate test in an additional cuvette will be compared to the initial test result. The results are considered to pass if they fall within the mean limits of 3 g/L.
Press [OK] to accept the results.
Remove the old cuvette and place a newly filled cuvette in the cuvette holder and close.
If the sample passes verification then the mean will be displayed, press [OK].
When the duplicate results fall out side the range the following will appear on the screen ‘Difference too large’.
REPORTING RESULTS
Results are reported to one decimal place.
PROCEDURE FOR DEALING WITH ABNORMAL RESULTS
Results obtained from HemoCue meters used in POCT locations are entered in the patient's case notes. In case of suspicion of abnormal results were obtained then repeat the test immediately. If the index of suspicion remains high, send the sample to the laboratory without delay. Ring the laboratory in advance to alert them to the incoming urgent sample.
1. Disinfection procedures for equipment:- The equipment should only require a wipe over with a damp tissue to remove dust. If blood is dripped on the instrument surface it should be removed using a tissue soaked in Trigene.
2. All waste should be disposed of in a sharp’s bin, which is replaced when ¾ full.
3. High risk samples are treated in exactly the same way; all samples are treated as high risk.
12. uncertainty of measurement
limitations / pitfalls / notes on the examination
1. Measurement of haemoglobin should be made as soon as possible after the cuvette has been filled, and definitely within 5 min
2. The optical eye of the cuvette should not contain air bubbles as this causes false results.
3. Take care not to contaminate the outer surface of the cuvette with either grease from fingers or from blood.
4. Values above 235 g/L must be confirmed by a suitable laboratory method.
5. Sulphaemoglobin is not measured by this method, and neither carboxyhaemoglobin nor hyperlipaemia interfere with the measurement.
6. Cyanmethaemoglobin standards cannot be used with this method.
linearity/analytical range/uncertainty of measurement
The manufacturer states that the method is linear to 256 g/L. This is also the limit of the analytical range for this method.
INTERFERENCES
· Filled cuvettes should be visually inspected for air bubbles before they are placed into the photometer. Small air bubbles within the circular section of the cuvette will affect the results; air bubbles around the edge do not influence the result.
· Measurement of haemoglobin should be made as soon as the blood has been drawn into the cuvette.
· Fingerprints on the measurement circle of the cuvette will interfere with the measurement of the sample.
13. reference range / action limits
Expected values:
Adult Male 130 – 170 g/L (13.0-17.0 g/dL)
Adult Female 120-150 g/L (12.0-15.0 g/dL)
Infants, after neonatal period 110-140 g/L (11.0-14.0 g/dL)
14. referEnces
Kit inserts:- See insert from HemoCue cuvette package, which lists the relevant bibliography.
15. APPENDICES
N/A
INDEX CODE BSF2POC003 v2 / TITLE HEMOCUE HAEMOGLOBIN 201 DM / Page 1 of 4Copies without an Authorised stamp or document manager signature are no longer valid after 7 days of this date 02/08/2010