This study is designed as a retrospective cohort study to evaluate the potential of diagnostic procedures in defining populations of patients self-reporting unexpected and uncontrollable episodes of body odor and/or halitosis. The cohort - generally healthy individuals who had underwent multiple diagnostic tests recommended by their physicians and had not been diagnosed with any known medical condition - expressed their interest in trying gastrointestinal and nutritional diagnostic tests offered by Biolab Medical Unit. Our retrospective analysis will determine if these tests were useful as potential screening tools for metabolic body odor and halitosis.

Many yet uncharacterized medical conditions including inborn and acquired errors of metabolism or skewed microbiome could be responsible for unpredictable and uncontrollable episodes of body odor and halitosis. These conditions have dramatic impact on the quality of life and socioeconomic outcomes of sufferers. Yet clinics and specialized malodor centers do not provide tests for diagnosing malodor other than trimethylaminuria (TMAU). Self-reported odor problems are often dismissed if are not organoleptically evaluated by trained odor judges that are not readily available during malodor flare-ups.

The aim of this study is to analyze effectiveness of existing gastrointestinal and nutritional tests for the assessment and investigation of self-reported malodors.

Diagnostic tests included:

• Gut Permeability Profile. PEG 400 is used as a probe and measured in urine passed for the following 6 hours at 11 different molecular weights to establish the quantity of each absorbed through the gut wall. Extraction and separation of PEG from urine is done by ion exchange chromatography and capillary GLC.
• Gut Fermentation Profile. Blood alcohols - ethanol, methanol, butanol, propanol and short chain fatty acids - are measured by gas-liquid chromatography.
• D-lactate test. D-lactate is measured by centrifugal analysis using the specific enzyme D-lactate dehydrogenase, which does not react with L-lactate
• The urine indicans (Obermeyer) test. Detection of indican in the urine depends upon its decomposition and subsequent oxidation of indoxyl to indigo blue and its absorption into a chloroform layer
• Breath test for small intestinal dysbiosis. Breath hydrogen and methane are measured by gas-liquid chromatography. The patient is given 10 gm of lactulose in 200 ml of water and alveolar air samples are collected every 20 minutes for 3 hours
• Functional B vitamins profile, by measuring the activation of a red cell enzyme that is dependent upon an adequate concentration of a particular vitamin for full activity. The assay relies on normal metabolism of the vitamin to its native form and the presence of other non-vitamin cofactors.

Inclusion Criteria:

• idiopathic malodor experienced over a period of several months or years
• willing and able to complete the study
• good general health

Exclusion Criteria:

• elect not to participate in the study

Individuals reporting idiopathic malodor production

de-identified individual participant data will be made partially available

All participants were followed up by email for at least one week after discussing their test results.

Adverse effects were defined as any events, expected or not, that affected participant well being, regardless of whether there was a causal relationship with the diagnostic testing and discussion of the results.

Serious adverse events were defined as those that prevented a participant from performing normal activities and required treatment.