That unprofessional, rule guideline, and/or law-breaking nurse was lying to you based on her own beliefs about what drugs people should be taking an how much autonomy patients should have in their treatment. If you are in the United States, it may be worthwhile to look into Hippa and other such things.
The only test I can think of that requires equipment or expertise they may not have at an free-standing urgent care clinic, off the top of my head, would be something like arterial blood gases, or perhaps not. Then there is certain radiology work like a lot of the tracer and other tests that the nuclear medicine specialists do as many of them require an MRI, Pet, Cat scanner or the use of a gamma ray camera, Geiger counter so on and so forth, as well as special carts and containers and other machinery and so forth for handling and using the isotopes . . . Then anything requiring karyotypes and looking for alleles in DNA is, in my experience, generally done at one centralised lab in a given clinic and hospital chain or sent to an outside laboratory and can take days to weeks . . . but a free testosterone level and other tests of the same sort, and other such tests are very straightforward and require tools they are going to have anyways.
Naturally, all of this is not to say that urgent care doctors and nurses are any different from the ones elsewhere in their organisations, in fact it was one very sweet urgent care clinic doctor from Croatia who steered me to a general practitioner who was sensible about narcotics for chronic pain when my old one retired.
A nurse long ago in the United States who thought she knew better than the general practitioner and all the other doctors, pharmacists, and others she worked with on my chronic pain case did something very similar about my Dilaudid script out in the waiting room and when I heard of others having this same thing happening, we called up the doctor and that nurse was sacked not long after that. Come on lady, if you want to be a doctor or a cop, go to school like everyone else . . .
I also got hassled about being on so much ER, IR, and SC/IV morphine by another urgent care doctor when I went in to get enough of the MS Contin for 36 hours until I could see my general practitioner on Monday to not only keep the pain down but keep me from having a heart attack because my Friday appointment was impossible to make because of a nationwide aeroplane travel clusterfuck, and said that I shouldn't be taking any narcotics and hadn't done anything else (an outright lie -- I told him where to look in my file to see all the things I have done and continue to do,, why the cause of the pain is inoperable, and had always had an integrated and multi-faceted chronic pain management programme, including seeing the general practitioner, six specialists, and regularly have a joint appointment with my general practitioner and the manager of the hospital dispensary who is also a professor of pharmacology -- one of these folks is an AODA specialist with whom all the narcotics contract people have appointments every 18-24 months or so -- always a clean bill of health in my case -- and the psychologist consulted before I went on narcotics round the clock who wrote that I was quite sane to such an extent that I would be a good risk for using Chronic Opioid Agonist Therapy for it and the urgent care quack just went "harrumph" and gave me my script) -- that arsehole was a one-man crime and ethics violation wave and I think spent some time in the pokey for diverting US CSA 1970 Schedule II and III controlled substances (stimulants and anabolic steroids for the most part, as well as narcotics like oxycodone, injectable pethidine and so on) and an astronomical quantity of Schedule IV ones, especially benzodiazepines . . . he was also busted for insulting the size of male patients' dicks and playing with patients' clits without asking them first and therefore was defrocked or whatever they call having their medical license and DEA number revoked. I think the guy literally prescribed Desoxyn (racaemic methamphetamine hydrochloride) for sinus infections and who knows what else, and he would write for stimulants and benzos and then buy them from the patients and barter other drugs to get the speed, and allegedly he would write for narcotics -- it just took a blowjob to get the script. He also requisitioned a lot of pharmaceutical C-Jam from the dispensary to what end we can only guess. He also stuck the end of a reflex mallet up a patient's arsehole . . . There was also a case when someone I know had an appointment with him and the doctor was passed out at his desk with phials of propofol, pentabarbitone, midazolam, and nalbuphine and a couple of syringes with hypodermic needles and other injection equipment like alcohol swabs, a tourniquet and so forth sitting on the desk -- this was apparently his lunch as his breakfast was probably Desoxyn or Phen-Fen . . .
Folks who are thinking of doing this should probably say that they are betwixt general practitioners and other doctors and they used to get that blood work done every 2, 3, 4, 6, 8, 12 months or whatever and you are overdue for it, and leave it at that. I know of injecting unsupervised drugs users who do not live near a needle exchange with a doctor on staff or other similar set up to help injectors who get tetanus shots every two to five years rather than 10+ or never who say that there is a newborn, immunocompromised, or immunosuppressed person in their family, or they will be travelling to Afghanistan, Madagascar or other places with poliomyelitis outbreaks and they should probably get their vaccinations up to date, as the tetanus vaccine is often a combined tetanus, poliomyelitis, and diphtheria vaccine.
If they have a laboratory where they do blood work there is no reason of which I can think that they would not be able to do a metabolic & endocrine panel . . . because of beta thalassaemia minor, labile metabolism partially having something to do with thyroid and a family history of thyroid trouble, as well as taking naproxen (which can cause gastrointestinal bleeding as well as bleeding elsewhere), and the elevated risk of osteomalacia, osteoporosis and so forth from long-term opioids, as well as catabolic steroids like dexamethasone and proton pump inhibitors like omeprazole, I get a complete blood count, kidney and liver function tests, troponin and myoglobin levels and other indicators of striated, smooth, and cardiac muscle damage, and comprehensive metabolic & endocrine panel, free testosterone, and related tests every three months and in the US I often went to the urgent care clinic a couple of blocks from my house in the evening to have the blood drawn. I would need to go in the evening to get in the 12 hour fast because I mainly had checkups, physicals, narcotics appointments and the like in the early morning, and they would have at least provisional results on some of it like A1C, cholesterol, haemoglobin, ferritin, red and white cell and platelet count, Vitamin D level, blood glucose, and at least some of the hormone levels within maybe 7 to 20 minutes so I would wait and see what they got . . . even the more involved immunoglobulin assays and the drugs tests that I get annually would have at least partial results in that same time frame, or perhaps closer to 30 to 45 minutes, and when they do the drugs test, it is testing for everything to make sure there have not been any changes in the metabolism of the drugs or any toxic byproducts piling up, and therefore go straight to the GC/MS and other tests and do both urine and blood samples