Warfarin Dosing Service (Wairarapa patients only)

What is the Wellington SCL (Wairarapa region) Warfarin Dosing service?

This is a service provided to patients of doctors in the Wairarapa region who are taking Warfarin. Our aim is to manage your Warfarin therapy safely and effectively.

Our service will:

  • provide you with support and ongoing education about managing your Warfarin therapy
  • require you to complete a patient questionnaire each time you have the INR blood test
  • provide you with Warfarin dosage and next test date information
  • forward a report of your test results and dose instructions to your doctor
  • consult your own doctor if issues arise that may affect your Warfarin therapy

General Information about Warfarin medication

Your doctor has put you on the medication Warfarin that belongs to a group of drugs known as anticoagulants. Although they are sometimes referred to as “blood thinners” anticoagulants do not actually thin the blood – instead they lengthen the time it takes for a blood clot to form. This makes it harder for clots to develop in your blood vessels and keeps existing clots from becoming bigger. 

A blood (INR) test is performed to determine the dosage of Warfarin that is right for you.  Blood tests will be required frequently when you first start taking Warfarin – whilst your body is getting used to the medication, and then at regular intervals for the duration of treatment. This is necessary because many factors can change the way our body responds to Warfarin over time, including diet, illness or other medications.

If your INR test result changes, the dosage of Warfarin may need to be adjusted - without this adjustment the medication either might not be effective or could lead to serious complications. Your dose is charted by a Wellington SCL Pathologist on the assumption that you have taken the medication as ordered since your last test. 

Potential Serious Side Effects of Warfarin Medication

The most serious potential side effect of Warfarin is bleeding; either internal or external. To deal with this possibility, become familiar with these warning signs:

  • Prolonged bleeding from a minor cut
  • Excessive or unexplained bleeding from gums or nose
  • Red or rust coloured urine
  • Black stools or blood in the stools
  • Tiny, round reddish or purplish spots on your skin
  • Pain in the chest, abdomen, pelvis or lower back
  • Unexplained swelling
  • Dizziness or fainting
  • Severe or prolonged headaches

If any of these symptoms develop – notify your Doctor IMMEDIATELY. If you are bleeding contact your Doctor or go to the Emergency Department of your local hospital at once. DO NOT WAIT FOR YOUR REGULAR BLOOD TEST.

Other Medications

Both prescribed and over-the-counter medications may interfere with Warfarin metabolism and should be discussed with your doctor.  Vitamin K affects how your body reacts to Warfarin. Don’t significantly increase or decrease your consumption of foods rich in this vitamin such as broccoli, cabbage, kale, lettuce, spinach, and green tea. Some yoghurt is supplemented with Vitamin K and should be avoided.

Blood Tests – Key Patient Information

  • Keep your appointments for blood tests, you will need to go to one of the WSCL Wairarapa Collection Centres listed below
  • Check your test results and get your next appointment by phoning the lab on 0800 420 012 or if calling from a ell phone call (04) 245 0224 after 3pm if you had your blood test done before 1pm or the next day if you had your blood test done after 1pm
  • Let the laboratory know if you would like a text message with your results
  • If you forget to ring – continue to take the prescribed dose and phone next morning for your dose and next appointment
  • We will ring you only if there is a significant change required to your dose
  • Take the dose of Warfarin prescribed.  It is recommended that you take it in the early evening and at the same time each day
  • Keep a dated record of your Warfarin doses
  • Maintain an adequate supply of Warfarin tablets
  • Let the phlebotomist know of any missed doses when you have your blood collected
  • Let the phlebotomist know of any new medicines started within the last 3 days
  • You will need to complete a patient questionnaire each time you are tested including
    • accurate, up-to-date personal details, including a contact phone number 
    • the dose of Warfarin you are taking
  • Get advice on over-the-counter medications from your doctor or pharmacist and ensure you tell your doctor if you have taken any medication they have not prescribed for you
  • When you need a repeat prescription or have any questions contact your doctor
  • If you are having dental surgery or an operation consult your doctor or surgeon with regards to your Warfarin requirements
  • If you are going away for an extended period of time or  over the time when your next test is due, discuss this with your doctor prior to your departure

Waiararapa Collection Centres


167 High Street South

Phone: (06) 379 8683

Fax: (06) 379 8693

Mon - Fri:

8.00am - 2.00pm


3 Clifford Square (by appointment only)

Phone: (06) 308 9220

Fax: (06) 308 8039

Mon - Fri:

8.30am - 10.30am


186 East Street

Phone: (06) 304 9012

Fax: (06) 304-8135

Mon - Fri:

8.00am - 12midday


5-7 Oxford Street, (by appointment only)

Phone: (06) 306 9501

Fax: (06) 306 9500

Mon - Thur:

8.30am - 10.30am

And alternate Fridays


24 Lincoln Road

Phone: (06) 370 3305

Fax: (06) 377 0702

Mon - Fri:

7.30am - 4.30pm


9.00am - 12midday

Wairarapa Laboratory 
Te Ore Ore Road


Phone: (06) 946 9836

Fax: (06) 946 9806


Mon - Fri:

8.00am - 4.30pm

Warfarin Service Contact Information

For all enquiries regarding the management of your warfarin therapy or dose information, please call 0800 420 012 or if calling from a cell phone 04 245 0224. Office hours are Monday to Friday 9.00am to 5.00pm.