Ask Our Doctors

Ask Our Doctors



If you are unsure as to which private blood test you need, or if you need a test at all, then use our contact page to ask one of our Doctors a question. We have put some examples below for you. There is currently no charge for this service.

Dear Blue Horizon Medicals,

I am taking T3 and the cells are not taking it up. I think it is either an imbalance of minerals or something to do with % saturation of the iron. Can you help.

LC, Bodmin.


Dear LC,

Assuming elevated T3, suggested tests if not already undertaken for thyroid hormone resistance:

  • Free T4
  • Reverse T3 can be tested to see if elevation of total T3 is due to non thyroidal disease, rather than failed uptake of T3 by cells
  • Pituitary studies as problems with thyroid resistance can overlap with pituitary resistance
  • Adrenal studies (cortisol/DHEA)
  • If available - DNA test for Thyroid Hormone Receptor beta gene (TR beta) (looking for mutation)
  • Iron studies (serum iron, transferrin saturation, TIBC, ferritin), Full blood count
  • Iodine levels
  • Selenium levels (selenium is required to convert T4 to active T3)

​In health, Duty Doctor, Blue Horizon Medicals.


Dear Blue Horizon Medicals,

Following on from my conversation with your office I wanted to check what the required time is that I would need to wait before having a private blood test to look for listeria.


I consumed undercooked turkey two days ago and am concerned that there may be risks to the baby as I am pregnant.


Please can you advise how soon I would have to wait to have the test to give an accurate reading, how effective the test is at identifying listeria risk to the baby, and confirm the name of the test so that if I was to go ahead I would be having it done at the right time without leaving it for long.

Many thanks for your help.


CM, Torquay


Dear CM,


The likelihood of your having Listerosis without symptoms of at least mild food poisoning is low, so the indication for private blood testing is not compelling unless you were unwell after eating the turkey.


The most reliable way to detect the organism is with blood cultures but this would usually only be carried out if you are unwell at the time of presentation.


Serial measurements of antibodies to Listeria in the blood will demonstrate whether or not it is likely that you have had a recent or previous infection. Rising levels of antibody between samples taken now and in 4 weeks time will indicate that recent infection would be likely. A similar level of antibody in both samples 4 weeks apart would suggest past infection, at some time - but it should be borne in mind that up to 53% of the population will carry antibodies to Listeria without any knowledge of previous infection from it. (2-6% of the population carry Listeria harmlessly in their gut). Two negative samples of course would suggest no previous exposure.


So, a rising antibody level between 2 samples would mean recent infection was likely, but a constant positive or negative result would mean recent infection is highly unlikely.

​In health, Duty Doctor, Blue Horizon Medicals.

Dear Blue Horizon Medicals,


I travelled to America over 12 months ago and began to feel poorly while I was there.
My symptoms were very sudden were I started with a fever and feeling hot, I had strong yellow smelly urine and body aches. I was in bed for most of my break I panicked about getting worse while in America however I managed to get myself home.
However my symptoms progressed to extreme bone pain my muscles seemed to waste away, I then began to have a series of stomach problems like burning around my abdomen I had lots of problems with my bowel activity, my kidneys felt affected and my eyes went yellow frequently. I felt very very poorly and did feel I was going to die. I spent a lot of time resting and in bed and only did a small amount of work
I have gradually got myself feeling much better although I am not fully back to feeling normal. I have been tested for celiac and had a lot of private blood tests - my doctor has said nothing is significant showing in the tests and they have not given me any answers or support. I am now getting stronger however since the onset of my illness I now find myself incredibly sensitive to most grain foods and I am extremely intolerant to alcohol. If I eat grains or drink alcohol it makes my symptoms flare up. Also there are other foods that seem to flare me limes and certain other foods make me feel like I have a hangover? During my illness my skin deteriorated and went very old looking like paper this is now improving. I also had bad days were I was losing sensation in my face and I basically looked like I was walking dead. I now am getting myself feeling better with a fresh food diet no preservatives or junk food or alcohol.
I have in the past drank probably too much even though I will admit it never has agreed with me. I also put my body through a lot of stress working and I did a lot of athletics for many years. Before the illness struck me I did have a lot of stress so it could have been caused by stress. However I just want to get myself feeling totally well again the problem is I cannot find what is causing these flare ups I now have and my diet is so restrictive. I think it may be autoimmune but my blood ANA test shows negative, It does state however weak Ro, La and Jo-1 antibodies this was in March however my doctor marked my results as normal? I have asked for my blood test results of all my other tests as I have had lots and not sure what they have and have not tested for? Can you advise me on what blood test urine test you think may be helpful for me to get tested so it could find some kind of diagnosis?


FJ, Salisbury


Dear FJ,


Sometimes the answer is not in the blood. It would be helpful to know what you have been tested for to date to as you won't want to incur unecessary further expense. If you can let us know I can fill any gaps, if indeed there any. I presume your Vitamin B12, folate and D levels have been checked?

 Weakly positive autoantibody results are usually of no significance. It sounds as if you initially were infected by something - possibly a virus, as you describe 'whole body' symptoms. Viral infections can be quite devastating, affecting many systems, followed by a slow recovery, as you have described. Unfortunately, very often nothing will show up on blood tests.

 However - you are improving which is of course good news. It may just be a matter of more time before you recover to your old self.

​In health, Duty Doctor, Blue Horizon Medicals.

Dear Blue Horizon Medicals,

I have been diagnosed as having an overactive thyroid for a year now and have had thyroid function tests every three months. The test I wanted was an endocrine test associated with the thyroid and a vitamin test as i am aware that a lack of vitamins or calcium can affect the thyroid. Which tests would you suggest?

GG, Reading

Dear GG,

Most cases of thyroid disorder have no detectable cause - thyroid tissue just fails to make enough thyroxine. Iodine (which is found in thyroxine) is sometimes deficient but this is a rare finding.

 If you know you have thyroid disease, treatment is needed - most doctors believe looking for a cause is not especially helpful.

 A general blood test will show up many underlying deficiencies if present - if you have not already had a full 'work up' from your usual doctor (I would think that is unlikely if you have been diagnosed with a thyroid problem) the comprehensive plus V test may fit your requirements.

​In health, Duty Doctor, Blue Horizon Medicals.

Dear Blue Horizon Medicals,

Thanks for getting back to me, I am not on any medication for thyroid as my tests at the doctors were normal, I have all of the symptoms of thyroid and have had them for more than 4 years I had the test done again as I have been on a strict diet for 3 months and my gym instructor advised me to get it checked as I am gaining weight I have gained 3 stone in 4 years and have been following a diet all that time ,and decided to do controlled programme so I could see what happened, under supervision from an instructor, I don't really know what test I should have, all I know is I have all the symptoms of thyroid, i.e. sleeping in the day ,low blood pressure, low heart rate, irregular heavy periods joint pain in arms and legs and now oedema in lower legs, so this is the thing that keeps coming up, I don't really know if anything else has the same symptoms and my doctor says it’s just old age, I am 52 ,do you have any suggestions at what test would be useful to get done?

LP, Guildford

Dear LP,

Thyroid function testing can be misleading - sometimes symptoms will develop before the blood reveals any clues. A low thyroxine level, with physical symptoms, would suggest that the thyroid gland is underactive. The trend is important, so a repeat test would be useful in 6-8 weeks’ time. Thyroid antibody testing is often recommended too as having these antibodies will increase your risk of having a thyroid problem.

​In health, Duty Doctor, Blue Horizon Medicals.

Dear Blue Horizon Medicals,

I have been eating very healthy for the last 6 weeks and following a comprehensive exercise routine.

In the past I have had rapid fat loss within a couple of weeks following this protocol but this time I’m yet to lose 1lb. Do you offer a blood test that maybe helpful in addressing my situation.


SA, Caterham


Dear SA,


I suspect that private blood testing is unlikely to reveal an underlying reason for this situation. If you are keen to eliminate an underlying medical reason, testing should look for problems that may reduce the metabolic rate (or rate of consumption of energy) or conditions that might lead to water retention.

Age is a consideration as we tend to gain weight more easily with passing years. Levels of activity are also important, as you are probably aware.

Baseline testing would include blood count, kidney function, liver function, thyroid function and glucose. You could go more 'in depth' but I would suggest running these tests first.

​In health, Duty Doctor, Blue Horizon Medicals.