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Urinary Neurotransmitter Testing: Spot vs 24 hour collections

Identifying and managing neurotransmitter imbalances is facilitated by a noninvasive urinary test. Labrix/Doctor’s Data neurotransmitter (NT) testing utilizes HPLC Triple Quadrupole MS/MS technology which is proving to be the most sensitive and accurate methodology for measuring urinary neurotransmitters. Testing can be run from either a spot collection or a 24 hour collection.


Spot collections have been validated for both first and second morning voids. Collecting the first void of the day provides a medium that can be tested before the impact of stress or foods. This is great news for practitioners testing children and adults who have difficulty continuing to fast until the second void of the day. Additionally, patients experiencing stressful morning schedules due to family matters, commuting, or strenuous exercise may want to consider choosing a first AM void, avoiding potential impact to the catecholamine levels in a second morning void.


Within the field of integrative medicine, the second morning void of urine had been the standard collection method for testing urinary neurotransmitters. The second void has its challenges, however, as patients should refrain from medications, food, exercise, caffeine, nicotine, large quantities of water, and stress before collection of this sample, which can be a challenge for some patients, especially children.


Doctor’s Data has completed in-house studies of spot collections and 24-hour urine collections. It was determined that for most neurotransmitters, the first morning void correlated best with the 24-hour collection. For the NT’s that are directly influenced by diet and daily stressors, one must decide whether it makes sense to identify the trough levels (first morning) or their average over the course of the day. Epinephrine and norepinephrine are especially reflective of stress, and tend to show a higher average in a 24-hour collection than is seen in a first morning collection. This may also be true of serotonin, 5-HIAA and dopamine which can be affected by ingestion of certain foods.


When doing a 24-hour urine collection, ALL urine during a 24-hour period must be collected and accounted for. The total volume is multiplied by the measured concentration. Reference ranges have been determined based on performing a complete 24-hour collection. If the collection is not done correctly, or the volume of urine is not measured correctly, then the results are not valid.


Like many standardized clinical laboratories, Doctor’s Data uses urine creatinine to calculate the excreted components in random urine samples. The primary reason for using creatinine for these purposes is that its excretion rate is consistent in patients with normal kidney function, and is an excellent indicator of hydration status of the patient. As such, creatinine is widely used to help standardize the reporting of the measured concentrations of excreted components in urine, and for many analytes has been a suitable and more convenient alternative to collecting a 24-hour urine sample. However, creatinine does have known limitations, including compromised kidney function, where excretion rates are not constant and/or restricted. In such cases, a 24-hour collection is highly recommended. 


To summarize:

Spot 1st or 2nd void:

Pros:

  • Morning baseline collection

  • One sample

  • Less influence from environmental stressors and foods

Cons:

  • Doesn't capture the variability of NTs and metabolites due to daily rhythms or the influence of stress and foods


24 hour urinary NT collection:

Pros:

  • Allows for the pooling of NTs (average excretion over a day)

  • Will be reflective of environmental influences of foods and stressors

  • The only viable option for patients with kidney disease

Cons:

  • Compliance. Collection of multiple samples over a 24 hour period is likely to result in at least one missed sample, which will skew results


While a first or second morning void is typically adequate for neurotransmitter assessment, in complex cases, it may be helpful to study an individual at a baseline level (first morning) as well as a 24-hour assessment which may better reflect the period of sustained elevation that occurs over the course of the day. 

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