Admin team get in touch to book a visit

  • Available dates will be suggested
  • Suitable date confirmed by phone/email
  • Travel reimbursement will be explained – Our research has a specific amount allocated for travel reimbursement. However, we regret we cannot reimburse other daily expenses.
  • Accommodation will be arranged where applicable
  • Complimentary sandwich lunch is offered at the visit

Visit packs sent out 2 weeks prior to visit

  • Appointment Letter
  • Flora kit (for stool sampling)
  • Urine kit
  • Questionnaires
  • Transport Information /map
  • Accommodation information (if applicable)

Confirmation call one week before visit

Travel to St Thomas' Hospital


For directions please visit you may also find London Journey Planner helpful:

Parking is very limited at St Thomas’ Hospital, so whenever possible we would encourage you to use public transport. Car park charges are displayed at the entrance and is a pay on foot facility so please make sure you have the correct change. Please note the hospital is within the congestion charge zone so you would need to factor this in to your travel claim.

Disabled Parking

Disabled Parking only

There is limited disabled parking bays at St Thomas’ Hospital. To be eligible for free disabled parking you will need to show your appointment letter to Main Reception with your blue badge in order to be issued with a free exit ticket to use at exit barrier.


Transport for london

Blue badge holders can also apply for exemption from the congestion charge – please visit transport for London’s website for further information

Preparing for your Twin Visit

  • Bring completed paperwork
  • Bring urine and stool flora samples (if applicable)
  • Bring lunch (if you do not want complimentary sandwich lunch)
  • Wear loose comfortable clothes and a top with sleeves that can be rolled up easily
  • Wear flat comfortable shoes that can be taken on and off easily
  • Please note you will be asked to remove any metal fastenings, jewellery or body piercings before having the bone density scan.

At the visit

Currently you may be offered some or all of the following tests that will take place both before and after lunch:

  • Sample collection such as hair, saliva and stool samples
  • Blood test (includes cholesterol and diabetes check) and DNA for analysis
  • Blood Pressure
  • Height and Weight
  • Lung Function Test
  • Grip Strength Test
  • Sensory Test
  • 2D photos looking at facial structures and ageing
  • Cardiac assessment (eligibility criteria apply)
  • Computer tasks assessing memory and cognition
  • Strength and balance test (non-strenuous)
  • Bone density DXA scan (can reveal future risks of fractures)
  • Skin assessment such as mole count
  • Taster Status Test
  • Biopsy such as a skin sample (eligibility criteria apply)

For a more detailed explanation of some of these tests and why we do them, please click here


Lunch Break (45 minutes) followed by further tests

Complimentary lunch includes sandwiches, fruit, biscuits, tea & coffee, soft beverages and a chance to meet other twins, followed by further tests.

Lunch Together

Your Feedback

After your visit you will be asked for your feedback so that we can continue to improve the twin visit experience.

Your data & samples

  • Your biological samples are sent to the lab for processing, logging and storage
  • The lab team performs DNA extraction using manual and automated procedures from whole blood and saliva
  • Your clinical & questionnaire data is entered into the secure database
  • The research team will use the data and sample analysis to explore current research questions

For a more detailed explanation of some of these tests and why we do them, please click here

Receiving your RESULTS

  • You will receive clinically useful results for you and your GP between 6 to 8 weeks after your visit
  • Cardiac assessment results (if applicable) will be sent separately
  • Some non-clinical results will be provided on the day
  • An example of a results letter can be seen by >CLICKING HERE.



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Why do you need my NHS number?

In order to request additional information about your health through linkage to medical records and other NHS trusted government research services supported by the Department of Health such as NHS Digital which provides cancer and cause of death information. The process involves us providing securely confidential details such as names, dates of birth and NHS numbers in order to receive the data. The data includes GP and hospital records of health measures, medications, diagnoses and visits. The extra data is extremely important for our research analyses.

Why have I been asked to send my blood for DNA by post?

For those of you who cannot visit St Thomas’ Hospital, we are trying to make it easier for you to donate blood so that we can use your DNA in
our studies. Due to the large number of studies that we are involved in, it is often necessary for us to replenish our DNA stocks

Why have I been asked to send other samples e.g. saliva, hair root, or stool samples?

DNA can also be extracted from other bodily tissues such as saliva, hair root and stool, analysis of which can offer different and valuable insights
into how our bodies work. We are also trying to make it as convenient as possible for you to participate in these important studies from home.

Do I need to come in for another visit if I have already been for a visit?

Yes. We have new studies all the time, and we are very interested in changes in your life-style and health as you get older. Research visits are
repeated approximately every four years.

Can I participate in a study or fill in a questionnaire even if my twin declines?

Yes. Although we would rather have both of you participating and understand that your circumstances may change, single responses or single visits are still useful to our research.

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