The Neurotoxic Metabolite Test (NMT) was developed by Belgian scientist Professor Kenny de Meirleir and is produced and distributed by Protea biopharma. Currently (October 2009) it has not yet been approved as a clinical diagnostic test and is therefore considered for research purposes only. However, many physicians treating have shown much interest in the test and it is now available through some of these and other distributors such as ProHealth Inc.
The NMT aims to detect the presence of abnormal metabolites in the urine. These metabolites are related to the production of hydrogen sulfide (H2S). Low levels of H2S in the body are normal as this gas is used much like nitric oxide (NO) and carbon monoxide (CO) as a signaling molecule. It is involved in the the regulation of blood pressure, neurotransmission, muscle relaxation, and inflammation. It also controls blood flow to the brain ad modulates the hypothalamic-pituitary-adrenal (HPA) axis - the stress control system. However in higher concentrations H2S becomes a potent toxin. Certain bacteria in the gut produce H2S which is then absorbed into the body. Therefore the NMT is designed to detect raised H2S concentrations associated with the growth of these gut bacteria.
Professor de Meirleir found that high urinary H2S metabolites are associated with overgrowth of Streptococcus, Enterococcus, and Pretovella bacteria in the gut. These bacteria ferment the food we eat to produce H2S. An overgrowth of such gut bacteria is termed 'gut dysbiosis'. Furthermore, Professor de Meirleir found that a significant proportion of chronic fatigue syndrome (ME/CFS) patients have such dysbiosis and test positive with the NMT test. The test is therefore aimed primarily at ME/CFS patients, although presumably it may also be useful in related conditions such as fibromyalgia.
Abnormally high concentrations of H2S have many detrimental effects in the body. In animal studies they have been shown to produce a hibernation-like state with decreased core body temperature, sleep apnea, reduced heart and respiratory rates, and a marked metabolic drop; symptoms familiar to those with CFS/ME and fibromyalgia. H2S also acts as a mitochondrial poison by inhibiting many enzymes involved in the production of ATP (energy). It also interferes with oxygen transport in red blood cells and the use of oxygen by the mitochondria. Also important in ME/CFS is the fact that H2S inhibits immune cells such as natural killer (NK) cells and T-lymphocytes and disrupts the HPA-axis.
Professor de Meirlier points out that high H2S may also result from metabolic disorders so these must be ruled out but a positive result in ME/CFS patients is likely to be indicative of gut dysbiosis with the H2S-producing bacteria named previously. Appropriate treatment may help such patients and is likely to involve antibiotics (natural or pharmaceutical) along with probiotics to restore the beneficial gut microflora.
The test itself is carried out at home and simply involves collecting a sample of first morning urine and adding a small amount to a plastic vile containing a special chemical reactant. If high levels of H2S metabolites are present the solution will change colour within 3 minutes.