Dr Charles Forsyth

General Medical Practitioner


In addition to conventional medical investigations, I use Biolab Medical Unit and a few other laboratories for less well known investigations.  Biolab has a superb range of nutritional and nutritionally related tests, thanks to Dr John McLaren-Howard’s pioneering work.  Below are some of the more common tests that I use, together with some explanation.  I am not keen on doing routine investigations on my patients - I far rather tailor tests to their individual needs, determined by careful history taking and examination - this is also more cost effective. 


Minerals, Trace Elements

These elements are essential to our health: Calcium, Magnesium, Phosphorus, Potassium, Sodium, Sulphur, Iron, Zinc, Copper, Manganese, Chromium, Selenium, Cobalt, Chlorine, Silicon, Iodine, Molybdenum, Vanadium, and possibly Boron, Strontium.  Mineral / trace element deficiencies are extremely common.  Most of these can be measured in a variety of samples, including: whole blood, plasma, red cells, white cells, urine, sweat, stool and hair.

The following are the tests I most frequently use for each element:

Magnesium: Red cell, plasma, hair, magnesium retention test

Zinc: Plasma, blood metallothionein (Acumen), hair, zinc challenge test

Copper: Plasma, Functional Superoxide Dismutase (Acumen), hair, copper response test, ceruloplasmin

Iron: Ferritin, Plasma, TIBC

Chromium: Plasma, HbA1, hair

Manganese: Plasma, hair

Selenium: Plasma, red cell, hair

Molybdenum: Plasma, Urinary sulphites, hair

Potassium: Serum, red cell

Sodium: Serum

Calcium: Serum + corrected calcium, hair, 24 hour urine

Iodine: urinary iodine, urinary iodine:creatinine ratio

Blood Minerals

The tests I use most commonly are:

  1. Plasma Mineral Profile with RBC Magnesium (Biolab: Ca, Cr, Cu, Fe, Mg, Mn, Se, Zn + RBC Mg) + Plasma Molybdenum.

  2. Serum Ferritin (available on NHS)

  3. Serum Iron + TIBC (available on NHS)

  4. Urinary Sulphite (Biolab)

  5. Urinary Iodine and Iodine : creatinine ratio (Biolab).

Hair Element Analysis

Hair analysis can be very useful in assessing nutritional and toxic levels of certain elements, and  has certain very definite pros and cons.

  1. Because the hair sample taken represents the last two month’s hair growth, the analysis provides an average level of each element over that period - there are few other tests that can give this kind of overview.  Other tests (blood, sweat, urine, etc.) mostly provide a result that reflects the situation now - both views are relevant. 

  2. The interpretation of a hair analysis requires knowledge and experience, particularly since elevated levels may not be what they seem.  This is particularly true for zinc: an elevated level almost always indicates a zinc deficiency, a level within reference range cannot be relied upon (may be a false negative), while a low level definitely indicates deficiency.  This is mainly because zinc is so essential for hair growth that deficiency slows down the growth rate and results in a greater zinc concentration in the hair.  Likewise high hair calcium usually indicates calcium deficiency, due to increased parathormone (PTH) secretion in response to nutritional inadequacy, increasing soft tissue calcium levels.  Hair iron levels do not correlate with body iron status at all, so is useless as an indication for iron deficiency. 

  3. Hair can be useful in assessing levels of the nutritional elements: calcium, chromium, cobalt, copper, magnesium, manganese, molybdenum, selenium, strontium, sulphur, vanadium, zinc and a few others.

  4. Hair may also be useful in assessing a wide range of toxic elements, see: Toxicology Investigations.

  5. Hair treatments, including colourings, perming, shampoos, conditioners, can alter hair element levels. 

For detailed instructions on taking hair for analysis, I have an information sheet ‘Collecting Hair for Hair Element Analysis’.  There are a variety of laboratories I use, depending on which elements I am wishing to know about:

Biolab: Calcium, magnesium, phosphorus, sodium, potassium, iron, copper, zinc, chromium, manganese, selenium, cobalt (12 = Ca, Mg, P, K, Na, Fe, Cu, Zn, Cr, Mn, Se, Co)

Micro Trace Minerals (MTM): Calcium, magnesium, phosphorus, sodium, potassium, iron, copper, zinc, chromium, manganese, selenium, cobalt + boron, germanium, iodine, lithium, molybdenum, strontium, vanadium (19: Ca, Mg, P, K, Na, Fe, Cu, Zn, Cr, Mn, Se, Co  +  B, Ge, I, Li, Mo, Sr, V)

Doctor’s Data: Calcium, magnesium, phosphorus, sodium, potassium, iron, copper, zinc, chromium, manganese, selenium, cobalt + boron, germanium, iodine, lithium, molybdenum, rubidium, sulphur, strontium, vanadium (21 = Ca, Mg, P, K, Na, Fe, Cu, Zn, Cr, Mn, Se, Co + B, Ge, I, Li, Mo, Rb, S, Sr, V)

Genova: Calcium, magnesium, phosphorus, sodium, potassium, iron, copper, zinc, chromium, manganese, selenium, cobalt + lithium, molybdenum, strontium, sulphur, vanadium (16 = Ca, Mg, P, K, Na, Fe, Cu, Zn, Cr, Mn, Se, Co + Li, Mo, Sr, S, V)

Mineral Lab: Calcium, magnesium, phosphorus, sodium, potassium, iron, copper, zinc, chromium, manganese, selenium, cobalt + boron, germanium, iodine, lithium, molybdenum, rubidium, sulphur, strontium, vanadium (21 = Ca, Mg, P, K, Na, Fe, Cu, Zn, Cr, Mn, Se, Co + B, Ge, I, Li, Mo, Rb, S, Sr, V)

Urinary Mineral Analysis

Urinary mineral measurements may be useful in assessing mineral status.  A 24 hour urine collection is usually most reliable.  Minerals can be measured individually or as a profile.  Most profiles available measure a selection of toxic and nutritional elements, these are the ones I mainly use:

Biolab: Toxic Element Screen (includes 7 nutritional metals): Chromium, cobalt, copper, manganese, molybdenum, selenium, zinc.

Doctor’s DataUrine Toxic & Essential Metals (includes 17 nutritional metals): Boron, Calcium, Chromium, Cobalt, Copper, Iron, Magnesium, Manganese, Molybdenum, Phosphorus, Potassium, Selenium, Sodium, Strontium, Sulfur, Vanadium, Zinc.

Micro Trace Elements (MTM):

24-Element Basic Profile (includes 10 nutritional metals): Calcium, Chromium, Cobalt, Copper, Germanium, Iron, Lithium, Magnesium, Manganese, Molybdenum, Selenium, Strontium, Vanadium, Zinc.

35-Element Nutrient & Toxic Profile (includes 14 nutritional metals): Calcium, Chromium, Cobalt, Copper, Germanium, Iron, Lithium, Magnesium, Manganese, Molybdenum, Selenium, Strontium, Vanadium, Zinc.

Sweat Mineral Analysis

Unfortunately this test has been discontinued.  Biolab was the only laboratory offering sweat analysis, where the test was developed by Dr John McLaren Howard in the early 1980’s.  In mainstream medicine the measurement of sweat sodium is used as a test for cystic fibrosis.  Nutritional minerals measured were: zinc, magnesium, chromium, manganese, copper and sodium.  Chromium, manganese and copper levels correlate well with plasma levels, while zinc and magnesium levels correlate well with intracellular levels.  A few toxic metals are also measured: nickel, mercury, lead, cadmium, aluminium.  You had to attend the laboratory for this test.  Method: a previously cleaned and weighed absorbent patch (7 cm x 3 cm) is taped to the patient’s back for 1 hour. The increase in the weight of the patch indicates the quantity of sweat collected. The trace elements are extracted from the patches with a mild acid solution.  If someone does not sweat easily it can be difficult to collect enough sweat for the test.


Biolab can determine blood levels of vitamins A, C, D, E, B1, B2, B3, B6, Biotin and the carotenoids alpha-carotene, beta-carotene, lutein, lycopene.  We also have functional blood tests for these B vitamins, vitamin B12 and vitamin K.  Functional tests measure the efficiency of a metabolic pathway that is dependent on the specific nutrient being tested - it usually more accurately reflects the actual requirement for the nutrient than measuring the blood level.  All these tests are done on a blood sample.

  1. Vitamin Profile (Biolab): Vitamins A (retinol), C, E (alpha and gamma tocopherol), alpha & beta carotenes, vitamins B1, B2, B6.  NB: does not include vitamins B3, B5, Biotin, B12, Folic acid, D or K.

  1. Vitamin A and Carotenoids:

  2. Vitamin A - retinol (Biolab).

  3. Carotenoids - plasma levels: Alpha & beta carotene (part of the vitamin profile above).

  4. Lycopene (Biolab)

  5. Lutein (Biolab)

  6. Beta-cryptoxanthin (Biolab)

  1. B Vitamins:

  2. Vitamins B1, B2, B6 functional tests (Biolab).

  3. Vitamin B3 functional test (Acumen or Biolab): functional test measuring RBC NAD activation.

  4. Biotin (Biolab) - a less well known but very essential B vitamin.  This is a functional test measuring pyruvate carboxylase activation in white blood cells.

  5. Plasma Vitamin B12 and Plasma & Red Cell Folic Acid (available on NHS, or Biolab).

  6. Active Vitamin B12 (Biolab) - holotranscobalamin - the metabolically active form of serum B12.

  7. Plasma Methylmalonic Acid (MMA; Biolab) - increases with increasing B12 deficiency.

  8. Urinary Methylmalonic Acid (MMA; as part of an Organic Acid Test, eg. Great Plains Lab) - increases with increasing B12 deficiency.

  9. Vitamin B5 - pantothenic acid (ELN, Holland via Biolab).

  10. Vitamin D:

  11. Vitamin D (25-hydroxy) Profile - vitamins D3 & D2 - (Biolab, or on NHS).

  12. 1, 25-dihydroxy Vitamin D (‘Active’ Vitamin D; The Doctor’s Laboratory, or on NHS).

  1. Vitamin E:

  2. Plasma Alpha and Gamma Tocopherol (Biolab).

  3. Vitamin E Profile: as above together with Delta tocopherol (Biolab).

  1. Vitamin K:

  2. Plasma Vitamin K1 (Biolab)

  3. Plasma PIVKA-II (undercarboxylated prothrombin) (Biolab).

  4. Undercarboxylated osteocalcin (ucOC) (Genova Diagnostics)/

      - These last two tests are functional measures of vitamin K status.

Essential Fatty Acids

  1. Red Cell Omega-3 and Omega-6 series and other fatty acids (Biolab).

Antioxidant  Tests

Superoxide Dismutase (SOD)

This is a vital antioxidant enzyme, of which there are a number of different forms, each with different areas of function.  I mainly use Acumen’s test that measures total SOD function and the three most important forms independently:

  1. Zinc/copper cytoplasmic SOD1, which protects the cell cytoplasm and is dependent on adequate zinc and copper status.

  2. Manganese mitochondrial SOD2, which protects the inside of mitochondria and is dependent on adequate manganese status. 

  3. Zinc/copper extracellular SOD3, which protects collagen and nitric oxide pathways and so has a relaxing effect on vascular smooth muscle.

The test includes assessment of the genes responsible for each SOD type and can identify whether the gene is blocked or deleted.  If blocked, the DNA adducts test will usually reveal what substance is causing the block.

Low SOD is associated with many diseases where oxidative tissue damage is occurring, including cancer, atherosclerotic diseases (heart attacks, angina, strokes, peripheral vascular disease), inflammatory diseases, and chronic fatigue syndrome.

Glutathione Peroxidase (GSH-Px)

This is a vital intracellular antioxidant enzyme, it’s function is to protect lipids from peroxidation, particularly those in cellular membranes.  It requires selenium as a cofactor and “mops up” peroxides by reacting them with glutathione.

Coenzyme Q10

This is a vital antioxidant enzyme that has a number of other vital roles.  Our production of it declines with age and decreasing mitochondrial function.  It is depleted by statin drugs (up to 40% reduction), some beta blockers and other antihypertensive drugs. Here are some facts about coenzyme Q10:

  1. It is the main antioxidant inside mitochondria - protecting mitochondrial DNA from damage.

  2. It is essential for energy production (as ATP), being a cofactor in the mitochondrial electron transport chain.

  3. It is essential in the formation of the apoptosome and other adapter proteins, the loss of which results in the breakdown of mitochondria.

  4. Inhibits protein and lipid oxidation in cell membranes.

  5. It helps to minimize oxidative damage to DNA.

  6. It protects LDL cholesterol from oxidative damage, thus protecting against atherosclerosis.

  7. It is essential for vitamin E regeneration.

  8. It stimulates the production of the antioxidant enzyme superoxide dismutase (see above).


This tripeptide is composed of the amino acids cysteine, glutamic acid and glycine, and plays a

major role in many processes:

  1. It is the major intracellular antioxidant, protecting intracellular organelles in particular from the damaging effects of the many oxidative and nitrosative substances formed during normal metabolism and xenobiotic detoxification.

  2. It is the substrate for the intracellular antioxidant enzyme glutathione peroxidase (GSH-Px).

  3. It is the substrate for the detoxification enzyme Glutathione S-transferase (GST), detoxifying many dietary and endogenous compounds and a wide range of xenobiotics and carcinogens, including toxic metals and many pesticides, solvents, drugs and other chemicals.

  4. It maintains the antioxidants vitamins C and E in their reduced (active) forms.

  5. It is involved in the regulation of the nitric oxide cycle - nitric oxide is a major biological messenger molecule involved in a variety of biological processes including blood vessel homeostasis (especially vasodilation), neurotransmission and the immune response.

  6. It plays a major role in many other biological processes, including immune function, DNA synthesis and repair, protein synthesis, prostaglandin synthesis, amino acid transport and enzyme activation.

  7. It is recycled (reduced) by GSH reductase (which is a vitamin B2 dependent enzyme).

Antioxidant Profile

Serum & red cell copper, ceruloplasmin, vitamin E & beta-carotene, red cell glutathione peroxidase (GSH-Px), red cell fragility, superoxide dismutase and platelet aggregation.

Serum Antioxidant Activity (Total & Nutritional)

The actual antioxidant activity of the serum is measured, as 1) serum total antioxidant activity and 2) serum total nutritional antioxidant activity.  The radical-scavenging antioxidants in human serum represent a heterogeneous group of substances, some synthesised in the body and some derived exclusively from the diet. Serum proteins, for example, can scavenge free radicals if they have available tyrosine or cysteine groups. Uric acid, which is also present in the serum in substantial concentrations, is another major free radical-scavenger. Circulating albumin and uric acid together provide the major source of antioxidant activity in normal human plasma.


Nutritionally Related Investigations

   INVESTIGATIONS: Nutritional  Gut  Toxins  Microbial  Mitochondrial  DNA Adducts