Hem-col® as an alternative for standard laboratory testing in the follow up of patients after bariatric surgery

In MC Slotervaart, one of the main medical centres for bariatric surgery,
routine blood checks are performed to evaluate vitamin status and several other
parameters in the follow up of bariatric patients. For this, patients have to
visit a laboratory to have their blood drawn through venipuncture.
Approximately nine different tubes of blood is drawn, requiring around 40
millilitres of blood. For analysing the blood, only a few millilitres is used.
The remaining blood is wasted.
Hem-Col® is a new blood drawing system produced by Labonovum B.V. that makes it
possible for patients to draw blood themselves at home using a finger stick.
Capillary blood is collected in a tube containing a special fluid which allows
storage of the blood sample for a few days before analysing. Patients can send
this blood sample to the laboratory for the assessments and do not have to
visit the lab themselves anymore.

The main objective of this study is to compare Hem-Col® as a method to draw
blood and measure the parameters used in the routine follow-up laboratory
checks after bariatric surgery to the present standard method at the laboratory
at the MC Slotervaart.
The second objective of this study is to measure how patient friendly Hem-Col®
is and if the product is indeed easy to use for our population.

We will conduct a method comparison study for validation of the Hem-Col®
system. Standard follow up moments, including blood checks, after bariatric
surgery are at 6 and 12 months and after that it is repeated annually. Patients
included in this study will have their blood drawn at one of these moments
through both methods at the same time. Both methods will be conducted by the
researcher. After this, collected blood will be analysed and the result of both
methods will be compared. At this time, patients will also get instructions for
using the Hem-Col® system themselves at home. Also, an instruction manual will
be handed out. Two weeks later, patients will be asked to draw blood themselves
through this new method. They will be asked to fill in a questionnaire at this
moment to evaluate how patient friendly the system is.

The procedure required for this study is almost similar to the current
procedure. Patients will have their blood drawn through venepuncture just like
they are used to do. The procedure will be extended with a few minutes because
a second method for blood drawing, through the finger stick. No great burden or
risks are associated with the Hem-Col® method. Using a finger stick can be
painful in some cases, but this is only for a short time and can be neglected.
After two weeks patients will draw blood through the Hem-Col® system again and
will send this to the laboratory. They will be asked to fill in a
questionnaire, which will require just a few minutes of their time.