Dr Charles Forsyth

General Medical Practitioner

 
 

The selection of tests for assessing toxins and their interpretation has to be made with considerable caution - everything is not necessarily what it seems.  Toxins are usually concentrated in different tissues to varying extents - they are not distributed evenly through the system - the level of a toxin in one tissue may be hugely different from another.  Fat soluble toxins concentrate in fatty tissues: brain and other nervous tissue, cell membranes and adipose tissue.  Lead concentrates particularly in bone, cadmium in kidney, etc.  Blood levels may be best for acute, relatively high dose exposure, but are usually not so appropriate when exposure is chronic and low level, because of the toxin being deposited in other tissues.  It is common for excretory pathways not to function efficiently, indeed this may be contributing to the toxicity, but it will result in excretory levels (eg. urine, sweat, hair, faeces) of toxins being misleadingly low.  For example in one study it has been found that there is an inverse relationship between the severity of autism and the hair mercury level - the poorer the mercury excretion, the worse the autism. In these situations provocation testing may be more useful - giving one or more substances that will displace or mobilise the toxin from where it is residing, eg. measuring urinary mercury before and after giving zinc, selenium and vitamin C, or a chelating agent such as DMSA.


The investigations described below are in addition to normal conventional investigations for liver & kidney function, haematology, thyroid & adrenal function, etc.


Nutritional status should always be assessed - toxins are toxic because they interfere with our biochemistry.   We are much more susceptible to absorbing and retaining toxins and to their toxic effects if our biochemistry is already compromised by nutritional deficiencies. 



Toxic Elements

Most toxic elements can be assessed in a variety of samples including blood (whole, serum or red cell), urine, sweat, hair, stool or other tissues.



Toxic Elements in Urine or Blood (Biolab)

Measures: Aluminium, Antimony, Arsenic, Barium, Beryllium, Bismuth, Cadmium, Chromium, Cobalt, Copper, Gallium, Germanium, Indium, Iridium, Iron, Lead, Lithium, Manganese, Mercury, Molybdenum, Nickel, Palladium, Platinum, Rhodium, Selenium, Silver, Strontium, Tantalum, Tellurium, Thallium, Thorium, Tin, Titanium, Tungsten, Uranium, Vanadium, Zinc, Zirconium.



Toxic Elements in Faeces (Doctor’s Data)

Mercury, Antimony, Arsenic, Beryllium, Bismuth, Cadmium, Copper, Lead, Nickel, Platinum, Thallium, Tungsten, Uranium



Toxic Metals in Sweat (Biolab)

As part of the Sweat Mineral Analysis: Aluminium, Cadmium, Lead, Mercury, Nickel.



Toxic Elements in Hair

All the following laboratories include a broad nutritional element profile - see: Nutritional Investigations.


  1. Biolab: Aluminium, Arsenic, Cadmium, Lead, Mercury, Nickel.


  2. Genova:

  3. Aluminium, Antimony, Arsenic, Barium, Bismuth, Cadmium, Gadolinium, Lead, Mercury, Nickel, Rhodium, Rubidium, Thallium, Tin, Uranium.

  4. Hair Toxic Element Profile: + Gallium, Germanium, Palladium, Platinum, Tellurium, Thorium, Tungsten.


  5. Mineral Lab: Aluminium, Antimony, Arsenic, Barium, Beryllium, Bismuth, Cadmium, Lead, Mercury, Nickel, Platinum, Thallium, Tin, Titanium, Uranium, Zirconium.


  6. Doctor's Data:

  7. Aluminium, Antimony, Arsenic, Barium, Beryllium, Bismuth, Cadmium, Lead, Mercury, Nickel, Platinum, Thallium, Thorium, Tin, Titanium, Uranium, Zirconium.

  8. Hair Toxic Element Profile: + Caesium, Gadolinium, Gold, Palladium, Tellurium, Tungsten.



Pesticides (Acumen)

This is a screen to determine the levels of a wide range of pesticides, herbicides, fungicides, including organophosphates, halogenated compounds (eg. Lindane), carbamates, pyrethroids, PCBs, PBBs and related compounds.  Serum levels are the most appropriate for acute exposures and for those compounds that are least fat soluble.  Fat cell levels are best for past exposure to fat soluble compounds.



Volatile Organic Compounds - in Blood (Biolab, Acumen), in Fat Cells (Acumen)

Aromatic Compounds: Benzene, Toluene, Ethylbenzene, Xylene, Styrene, Trimethylbenzene, Dichloromethane, Chloroform, Trichloroethane, Trichloroethylene, Tetrachloroethylene, Dichlorobenzene, Bromodichloromethane, Carbon Tetrachloride.

Aliphatic compounds: N-Pentane, Cyclopentane, Methylpentane, Methylpentane, N-Hexane, N-Heptane.



Glutathione S-Transferase (GST) (Acumen)

GST is a family of enzymes that detoxify by conjugating reduced glutathione to a wide variety of potentially toxic substances.  This test is very useful as an initial screening to identify whether xenobiotics may be contributing to disease.


Serum GST: is liver-derived and an increased level reflects increased exposure to hepatotoxic chemicals that are, at least partially, detoxified by glutathione conjugation in the liver.  This includes many drugs, pesticides and volatile organic solvents, eg. dry cleaning fluids. Affinity chromatography can reveal abnormal enzyme bands which reflect alterations in the way enzyme sub-units are assembled.    Much less frequently, it may reflect attempts to detoxify excessive tissue-breakdown products.  Occasionally, a genetic variant of the enzyme may be detected.


Red cell GST is unrelated to liver GST.  In the red cell, the enzyme is concerned with the detoxification of metals.  An abnormal enzyme band in the affinity chromatography pattern of the red cell GST reflects exposure to a specific toxic metal.  When a discrete enzyme band is present in the affinity chromatography of the red cell GST the protein fraction is eluted and atomic emission analysis is used to try to identify the causative metal.  This is one of my favourite screening tests for toxic metals, along with Metallothionein (below).



Metallothionein (Acumen). 

Metallothionein is a blood transport protein for zinc, copper and toxic metals.  This is one of my favourite screening tests for toxic metals, along with red cell Glutathione S-Transferase.

The test measures the total amount of metallothionein and the percentage and identity of metals bound to it.



Urinary Porphyrins

This is a useful screening test when environmental toxins are suspected.  Urinary porphyrins are oxidized intermediate metabolites of haem synthesis and alterations in them may be associated with genetic disorders, metabolic disturbances/diseases, poor nutritional status, oxidative stress, and exposure to certain toxic chemicals or metals.  Specific urinary porphyrin patterns may be associated with mercury, arsenic, lead, aluminium and some toxic chemicals, eg. hexachlorobenzene (HCB), polyvinylchloride (PVC), polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), dioxins, some pesticides.

Several laboratories offer urinary porphyrin profiling:

  1. Metametrix  www.metametrix.com/content/DirectoryOfServices/0060PorphyrinsProfile

  2. Doctor’s Data  www.doctorsdata.com/test_info.asp?id=125

  3. Laboratoire Philippe Auguste  www.labbio.net/index.php?page=porphyrines_en



DNA Adducts (Acumen)

A wide range of substances are able to stick (‘adduct’) to DNA, change it’s structure and shape, and interfere with replication, transcription and DNA repair mechanisms.  DNA adducts may thus either activate or block the expression of genes.  This can have a huge range of metabolic effects, depending on which gene an adduct is on or near and which enzyme/protein the gene codes for.  If an oncogene (cancer predisposing gene) is activated or an anti-tumour gene is blocked, there will be increased predisposition to cancer - this is one of the main ways carcinogens may cancer.


This ground breaking investigation detects, identifies and measures the quantity of substances adducted to DNA.  For more details, see: New Investigations



Mitochondrial Tests

  1. ATP Profile - usually indicates whether there is toxic blocking; to identify the toxins responsible, Translocator Protein Studies are required (below).

  2. Mitochondrial Translocator Protein / Mitochondrial Membrane Studies (Acumen)

  3. Mitochondrial Respiration Studies (Acumen)

  4. Cardiolipin Profile (Acumen)


Toxins may interfere with mitochondrial function in a number of different ways:

  1. Block oxidative phosphorylation

  2. Block translocator protein (which moves ATP & ADP across the mitochondrial membrane)

  3. Adduct to mitochondrial DNA

  4. Block the enzyme that makes cardiolipin (a vital membrane lipid exclusive to mitochondria)

  5. Uncouple oxidative phosphorylation from the electron transport chain


For more details, see: New Investigations



Lymphocyte Sensitivity Tests


Acumen

Acumen offer a small range of lymphocyte sensitivity tests for metals (including mercury, nickel, lead, cadmium, silver and gold), pesticides, volatile organic compounds (eg. formaldehyde, benzene, styrene, etc.), silicones, latex and a range of other xenobiotics.  Lymphocytes are separated from a blood sample and incubated with heat-activated microscopic glass beads.  The adhering lymphocytes are then visualised by video-phase contrast microscopy.  Microcapillary electrodes are used to measure the resting potential of a series of lymphocytes and minute quantities of the test substance are directly applied to the cell membrane.  The change in resting potential is recorded for a sufficient number of cells to give a reliable indication of the degree of sensitivity.  For each test substance, we report a numerical value derived from the average change in resting potential.  Values below 100 are considered to be normal.  Values up to 1000 are seen in a marked sensitivity.


Melisa

Melisa (Memory Lymphocyte Immunostimulation Assay) detects Type-IV allergy to metals, chemicals, environmental toxins, drugs, Candida, moulds, gluten and Lyme disease.  See Melisa.



Toxic Effects Test (Acumen)

I consider this test to be a major breakthrough as it is the first clinically available test that actually measures to what extent a potentially toxic substance is currently inhibiting cellular function in a given patient.  The test first measures the metabolic activity of mixed white blood cells and then the percentage inhibition of this by the substance(s) being tested.  This test was introduced in early 2011 and is proving to be of considerable benefit for: 1) measuring this important marker of how toxic a substance is in the individual patient, 2) prioritising treatment for those substances that have the greatest toxicity where multiple toxins are involved, and 3) monitoring the effectiveness of detoxification. But it should be noted that it does not replace other tests that identify specific binding sites for toxic substances, eg. DNA Adducts, Mitochondrial Translocator studies, etc.

 

Toxicology Investigations

   INVESTIGATIONS:    Nutritional     Gastrointestinal     Toxins     Others      New Tests