Trockenblut

Trockenblut, usually called dried blood spot or DBS in the literature, is a collection method rather than a test. A small amount of capillary blood is placed on a defined filter card, dried, and sent to the laboratory.

The appeal is the logistics, because a dried card is stable at room temperature and can be sent by ordinary post, which removes the courier window that a liquid sample needs, and that window is the hardest part of Probenlogistik. It also makes collection outside the pharmacy possible, since a customer can complete the card at home.

The limits are equally clear, and there are three of them:

• The volume is small, which limits how many analyses one card supports.
• Not every analyte is validated for the method, so the panel is narrower than a liquid sample allows.
• Results come with method-specific reference ranges and are not interchangeable with values from a liquid sample.

The last of those matters most when a customer compares a new result against an older report. Card quality is part of the result as well. Spots that are too small, overlapping, applied in layers or dried in the wrong conditions get rejected, and the customer completing the card at home is the person least likely to know that.

For a pharmacy, Trockenblut is a third option next to the two obvious ones:

• A kapillare Blutentnahme at the counter suits a focused panel with a quick answer.
• A venöse Blutentnahme suits a broad panel with many analyses on it.
• Trockenblut suits follow-up measurements and customers who will not come back for an appointment.

Whether a given analysis is offered on Trockenblut at all is decided by the akkreditiertes Labor, since the method has to be inside its accreditation scope.