Dr Charles Forsyth

General Medical Practitioner



In mainstream medicine in the UK we usually don’t have to think twice about doing an investigation to confirm or refute a suspected diagnosis if it is at all important.  The reality is of course that all investigations come at a cost - some are inexpensive but some can be very expensive - and the choice of whether to do a test or not depends on quite a number of factors, which may include:

  1. Are they necessary - will they make a difference to any of the following?

  2. Are they to detect or exclude potentially life threatening disease (eg. cancers, unstable vascular, pulmonary, gastrointestinal, neurological disease, etc)?

  3. Will they help clarify diagnoses and their underlying mechanisms and potential causes?

  4. Will they help the selection and prioritisation of treatments/interventions - and thus potentially speed up the rate of recovery?  For example, will they help reduce difficulties in deciding what and what not to do and reduce some of the guess work?

  5. Will they help in monitoring progress and effectiveness of treatment?

  6. Will they help if progress is (or has been) much less than expected, despite apparently appropriate treatments?

  7. Will they help clarify prognosis and expectations, eg. likely speed of recovery?

  8. Cost - how much can they or should they be afforded?

It is well accepted that around 80% of diagnosis is derived from taking a good clinical history.  Investigations should never replace a thorough clinical history followed by appropriate physical examination.  Treatment (or management) should always be determined by a good understanding of what is going on in the patient.  It should be obvious that the more accurate one’s understanding of the whole picture, and especially the underlying mechanisms and causes, the more likely one is to select the most appropriate interventions and the quicker progress is likely to be.

Many of the patients that I see have already been reasonably thoroughly investigated along conventional lines, and when this is the case, will usually not need further conventional tests, unless it is important to recheck previously abnormal results.

The majority of the investigations that I use are aimed at trying to identify and prioritise the underlying mechanisms and fundamental causes of why a patient has their health problems.  If one can accurately achieve and address these, the patient usually starts improving - in fact if they don’t it usually means that one has either not identified all the most important factors or one is not addressing them adequately.  Please see my information sheet Ecological Medicine for more discussion on this topic.

If one’s budget is quite limited one can often get away with doing a small number of investigations and work on the basis of suspected diagnoses and suspected priorities.  Because we are just so unbelievably complicated and each individual is absolutely and totally unique, we can never know all the factors involved - so medicine is still an art as well as a science, however much we investigate, and for this reason I regard the whole of medicine to be experimental, when it comes to treating an individual - there is always a substantial degree of educated guess work involved.  But my aim is always to try and reduce the latter as much as possible.


I use a wide range of laboratories for medical investigations. 

For investigations available in mainstream medical laboratories I mainly use large London based medical laboratories such as The Doctor’s Laboratory and The London Clinic as they provide very high standards and competitive prices.  Most of these tests are therefore available on the NHS - your GP or specialist may be happy to arrange these for you on the NHS, but is also dependent on whether your local hospital laboratory is willing to do them.

However the majority of the investigations I use are very specialised and are only carried out at certain very specific laboratories and are definitely not available on the NHS.  Most of these tests are well validated with research published in peer-reviewed medical scientific journals, but some are not.

Quality assurance is essential in clinical laboratories for the provision of precise, reliable and accurate analytical results.  All the laboratories that I use have very high standards of quality control and all participate in quality control schemes, nationally and often internationally.  However many are not able to obtain CPA (Clinical Pathology Authority) certification because they carry out one or more investigations that are not done by any other laboratories (so they are unable to share and compare samples and analytical results). 

One of the laboratories that I use extensively is Acumen, the director is Dr John McLaren-Howard, who was head biochemist at Biolab from it’s founding in 1984 until 2007 when he founded Acumen.  Acumen is at the very cutting edge of medical research with most of their investigations, the majority of which are therefore not available anywhere else in the world at present.  Acumen states in their position paper “national or international quality control schemes are not available for many of the tests offered. The responsibility for establishing and monitoring accuracy and reproducibility remains with us and we take this very seriously.  In addition to in-house control procedures and the use of commercially available standard reference materials, we exchange samples with other laboratories and constantly explore ways of improving our results”.  Both Dr John McLaren-Howard and others who work or have worked at Biolab have produced a great many research publications; some of John’s latest include those on the ATP Profile (mitochondrial function test) that he developed.  For the vast majority of Acumen’s tests there is extensive independent research and publications concerning the basic science involved and the techniques that are used.

It must be emphasised that the vast majority of mainstream GPs and specialists will have no knowledge or understanding of many the investigations that I do, so will be at a loss when it comes to interpretation and making sense of their significance, and will not be able to find out anything about them in the usual places they might look for information, eg. PubMed.  But please remember that I am always happy to discuss any aspect of your management and the work that I do with your medical carers.


In addition to regular mainstream investigations, some of those that I commonly use can be loosely divided into a variety of areas, including:

What I regard as Fundamental Mechanisms:

  1. Nutritional - Vitamins, minerals, fatty acids, amino acids, etc.  See Nutritional Investigations.

  2. Toxicological - Endogenous and exogenous.  See Toxicological Investigations.

  3. Microbiological - Systemic and local infections, dysbiosis and gut flora (intestinal microbiome), etc.  See my information sheets: Microbiological Investigations, Infections Contributing to Chronic Disease, Fungal and Bacterial Dysbiosis.

  4. Genomic - genetics (and epigenetics) - eg. relating to detoxification pathways, methylation cycle, etc.  See Methylation Cycle Investigations.

Systems and Processes:

  1. Allergy, Sensitivity, Intolerance - Total IgE, Coeliac tests, RAST (IgE) and sometimes IgG allergy tests, etc.

  2. Antioxidant Enzymes - Superoxide dismutase, glutathione peroxidase, coenzyme Q10, paraoxonase, etc. See my information sheet: Antioxidants.

  3. Gastrointestinal - Tests for dysbiosis, parasites, leaky gut, malabsorption, pancreatic enzyme insufficiency, low stomach acid, mucosal inflammatory markers, secretory IgA (mucosal immunity), faecal occult blood and red cells, etc.  See Gastrointestinal Investigations and my information sheets about each subject.

  4. Metabolic - Homocysteine, histamine, mitochondrial, metallothionein, etc.  See my information sheets about each subject.

  5. Detoxification Pathways - Liver enzymes, glutathione-S-transferase studies, etc.  See my information sheet: Detoxification Program.

  6. Endocrine - Thyroid, adrenal, sex hormones, parathyroid, melatonin, etc.  See my information sheets: Hypothyroidism, Adrenal Dysfunction.

  7. Autoimmune - ESR, CRP, autoimmune profiles, etc. See my information sheet: Autoimmune Disease.

  8. Immune - FBP, immunoglobulins, Lymphocyte subsets, etc.


The majority of the tests I request can be done through Biolab - this is very convenient for most patients as everything can be done in one place and the staff at Biolab are very familiar with everything that needs to be done.

Most tests require a pathology request form completed and signed by me - which I either give to you at our consultation or can post to you. Some tests requiring kits I might order to be sent to you by email or phone.

Some tests require samples to be collected at home, eg. urine, stool, hair, saliva tests.  For any of these you will be provided with the appropriate lit and full instructions.

If it is difficult for you to get to Biolab for a blood test, it is possible to send the blood for most tests (but not all) by post.  If you wish to do this, you will need to:

  1. 1.Phone the relevant laboratory (their phone number will be on the request form) for the blood sampling kit to be sent to you.

  2. 2.Find a phlebotomist local to you to take the blood - this can be your GPs practice nurse/phlebotomist (if they are willing), your local NHS hospital phlebotomy department (they are usually happy to do this - all you have to do is walk in with the kit in the morning), or failing these, a private local hospital (BUPA, etc).

  3. 3.You will then have to post the samples by next day delivery to the laboratories, together with the request form I have completed and a cheque.  The samples must not to arrive at a weekend, and preferably not on a Friday.

Investigation Fees

Please be absolutely clear about the fees for the tests before you have them done! 

For tests arranged through Biolab, please phone Biolab and obtain an accurate total price for those that I have requested, and if you are happy with the cost, book a suitable appointment.  I usually list the prices of Acumen tests on their request form.  If you consider the total price of the tests to be more than you want to afford at present, please ring my office to arrange a telephone consultation to discuss the priorities to try and fit your budget.

Your NHS GP might well be happy to arrange for you to have conventional investigations that are available at NHS laboratories, so as to save you the cost of these.

Medical health insurance - there are now very very few health insurance companies that recognise me (and most of my colleagues) as a specialist.  If  yours does, and you wish to try and claim the cost of laboratory fees from them you MUST first check with them whether they will cover the cost of any of the specific investigations I am requesting.  If they will not cover the costs of tests requested by me, they might do so if the tests are requested by a mainstream specialist/consultant (and sometimes your GP) - but this is dependent on the doctor being happy to do so.

All investigation fees will need to be settled with the relevant laboratories at the time the samples are collected or sent off.  Biolab will accept payment by credit card, cheque or cash but samples for Acumen tests must be accompanied by a cheque at the time they are sent.

Investigation Results

Test results are always sent directly to the doctor who requested them, and when in paper format, usually in duplicate.

How long it takes to receive a test result is dependent on the specific test.  Some come through within days, some may take up to four weeks - the latter is particularly true of those that go to USA or European laboratories.  So I generally advise patients to make an appointment to see me to review their test results for about a month or more after the last sample has been taken or sent off.

I always give my patients a copy of their test results, together with annotations indicating whether they are normal, borderline, abnormal or very abnormal.

I always like to discuss the test results in detail with the patient so that they can hopefully understand what each test means, it’s significance and relevance and what we can usually do to improve the abnormal ones.  For the vast majority of the unconventional tests that I do, the more abnormal a test result, the more optimistic I am that correcting it will have a major impact on symptoms and health (eg. correcting almost any severe nutritional deficiency).  I usually provide a summary of the test results in my letter to the patient together with my suggested action plan.  Additionally I have information sheets that explain most of the investigations, their significance and relevance and management options.

Investigations / Laboratory Tests

   INVESTIGATIONS: Nutritional  Gastrointestinal  Toxins  Microbial   Others      New Tests