haematology users' handbook - University College London Hospitals

Routine Coagulation (page 1 of 2)
Autolab 1 st Floor, Whitfield St Laboratories, 60 Whitfield St London W1T 4EU Tel: 0203 447 8547 or x 78547
• Citrated samples must be adequately filled (a 9:1 blood:citrate sample ratio is required for all citrated samples). Tests cannot be performed on underfilled,
overfilled, haemolysed or clotted samples.
• Paediatric citrated tubes are issued from the Haemostasis Laboratory to the Neonatal Unit, Paediatric A&E and Phlebotomy Outpatient departments and
can be issued to other locations on request: contact x78549/78545 during routine hours.
• Include clinical details on the request form, e.g. “patient receiving Warfarin/Heparin therapy” or “post op”; to facilitate appropriate testing and
interpretation of results.
• Send the request form and sample to the laboratory as rapidly as possible; notify the laboratory regarding very urgent requests on ext 78547 (during
routine working hours) or Bleep 7060 (out of hours).
• Grossly lipaemic samples may require manual testing, potentially delaying results.
• Abnormal results that require further laboratory investigation and/or manual testing/confirmation may be delayed.
Test
Coagulation
screen
PT/INR, APTT,
TT, Fibrinogen
Specimen
type
4.5ml Sodium
Citrate
Key Factors
affecting tests
Heparin &
Warfarin.
Delayed receipt of
sample.
May not be
possible on
grossly lipaemic
samples.
Note Reference Range Out of hours
service
Heparin & warfarin
therapy affects results
and determines
appropriate testing
please indicate that the
patient is on heparin
and/or warfarin on the
request form.
PT: 10-12 secs
APTT: 25-37 secs
TT: 15.5-18.5 secs
Fib: 1.5 – 4.0 g/L
Service for
clinically urgent
requests
Time Limit
for
requesting
additional
tests from
time of
venesection
5 hours Urgent:
1hr
Turnaround time
from receipt of
sample
Nonurgent:
4 hrs
HAEM-PD-UserHbook V8 Haematology and Blood Transfusion User Handbook Page 18 of 38
Authors: Karen Orfinada (Senior Biomedical Scientist)
Sally McDonald (Senior Biomedical Scientist) Authorised by: Dave Barnett Review Date: August 2015