I recommend you find a copy of the MDR regulation (2017/748) and the IVD Regulation (2017/746), I have quoted the definitions below. Its best for you to decide whether your products are a medical device or not; or an In-vitro diagnostic or not. Once you decide that, you can work out the class of the product and whether you need a UDI.
From MDR
(1) 'medical device' means any instrument, apparatus, appliance, software, implant, reagent, material or other article intended by the manufacturer to be used, alone or in combination, for human beings for one or more of the following specific medical purposes:
– diagnosis, prevention, monitoring, prediction, prognosis, treatment or alleviation of disease,
– diagnosis, monitoring, treatment, alleviation of, or compensation for, an injury or disability,
– investigation, replacement or modification of the anatomy or of a physiological or pathological process or state,
– providing information by means of in vitro examination of specimens derived from the human body, including organ, blood and tissue donations,
and which does not achieve its principal intended action by pharmacological, immunological or metabolic means, in or on the human body, but which may be assisted in its function by such means.
The following products shall also be deemed to be medical devices:
– devices for the control or support of conception;
– products specifically intended for the cleaning, disinfection or sterilisation of devices as referred to in Article 1(4) and of those referred to in the first subparagraph of this point.
(2) 'accessory for a medical device' means an article which, whilst not being itself a medical device, is intended by its manufacturer to be used together with one or several particular medical device(s) to specifically enable the medical device(s) to be used in accordance with its/their intended purpose(s) or to specifically and directly assist the medical functionality of the medical device(s) in terms of its/their intended purpose(s);
From IVDR
(2) 'in vitro diagnostic medical device' means any medical device which is a reagent, reagent product, calibrator, control material, kit, instrument, apparatus, piece of equipment, software or system, whether used alone or in combination, intended by the manufacturer to be used in vitro for the examination of specimens, including blood and tissue donations, derived from the human body, solely or principally for the purpose of providing information on one or more of the following:
(a) concerning a physiological or pathological process or state;
(b) concerning congenital physical or mental impairments;
(c) concerning the predisposition to a medical condition or a disease;
(d) to determine the safety and compatibility with potential recipients;
(e) to predict treatment response or reactions;
(f) to define or monitoring therapeutic measures.
Specimen receptacles shall also be deemed to be in vitro diagnostic medical devices