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What do 24 hr urine pre-chelation (native elimination) and 24 hr urine post-chelation really mean?

What do pre-chelation and post-chelation really mean. The starting point is to go over what I have written in prior blogs. I always get pre-chelation urine within a few days prior to chelation and post-chelation starting about 1 hour (so missing the very first urination post chelation (hopefully the first urination is either towards the very end of chelation or right afterwards. I do these as 24 hr.. This applies to all heavy, metals, not just Gd) So to step through these points:

  1. Prechelation urine (also called unprovoked, I like the term native urine elimination) represents the amount of Gd that the body is spontaneously eliminating on its own. In part it represents the ability of the body and kidneys to eliminate Gd and in part it reflects how much of the heavy metal is loosely bound, and hence readily eliminable. The state of renal function strongly influences this. The durability of retention of the heavy metal also strongly influences this. In absolute terms: how transient vs how persistent is the heavy metal retention.

  2. Post-chelation urine simply reflects how much more Gd comes out of the body compared to native elimination. It is however the most important metric of determining how effective a chelator is at removing from the body Gd or any other heavy metal. If a heavy metal does not increase in amount post chelation, may mean that there is not much of that metal present in the body, but equally it may reflect that the chelator is not effective at removing the metal. It also does not describe if re-distribution is occurring. The stability constant is the best predictor if much re-distribution is likely to occur. Always the chelator with highest stability constant should be used, which is also able to pick up the heavy metal in vivo.

  3. Post-chelation urine. I measure following full dose Ca-DTPA, because Ca-DTPA removes the most heavy metal of all chelators, but also the most with minimal redisposition. EDTA may also remove a lot of Gd but redistributes a fair amount (I estimate 30%). DMSA also can remove a fair amount of Gd but redistributes even more (> 50%). In simple terms, redistribution means the chelator can pick up Gd in skin, immediately re-release it, so they Gd can now go to brain. This is always a bad thing.

  4. 24 hr urine. Why not spot urine or 6 hr? One chelation practitioner at one time said to me I prefer to use DMSA because you only have to do 6 hr urine... I use 24 hr urine to increase the accuracy of that measurement, since there almost certainly is diurnal variation in the amount of Gd eliminated. Even more critical is the timing. We start about 1 hr post chelation, after the first post-chelation urine. Standardization is crucial.

  5. The time intervals between chelation are important to determine the change in amount of Gd elimination. Generally we like an interval of 3 weeks. Comparing urine study of a shorter interval (eg: 1 week) compared to an interval of 4 weeks, the one week interval will artificially be lower than 4 weeks, because less time has been allowed for Gd to re-equilibrate from bone, back to skin. The longer the time between chelation sessions, the more Gd that will be eliminated, but this is a function of re-equilibration, not anything to do with the heavy metal or renal function (unless renal function has changed dramatically).

  6. A 3 month interval between chelations probably is the time point where relatively stable re-equilibration has occurred. One year though may be the best. Note it is critical not to misinterpret at one year after the last chelation, a pre- and post-chelation urine showing a relatively high amount of Gd, this does not reflect that chelation has failed to remove Gd or any other misinterpretation, it reflect that a fair amount of Gd has re-equilibrated from bone back to skin and other soft tissue organs. The Total body Gd content is lower. This is different from essentially all other heavy metals where continued incorporation/consumption.of heavy metal (eg: lead) is likely ongoing.

  7. A significant amount of total body Gd removal is appreciated when the post-chelation urine starts dropping into the low yellow range, and out of the red (eg: 5 mcg,when earlier was 20 mcg).

  8. If urine Gd remains at a high level 20 mcg/ 24 hr does not mean that chelation is failing to remove Gd, it means that Gd is re-equilibrating from bone back to skin and soft tissue. This is a very good thing. It is critical to reduce total body Gd content to achieve near cure, which means critical to remove Gd from bone

  9. Removal of Gd from tissues and bone is often not a pure linear process, and not uncommonly later chelation 24 hr urines may show a bump in value. This reflects a number of processes (some described above) but it appears removal from bone is not a steady stream, but more akin to icebergs of Gd breaking off. Amount of physical activity (more activity resulting in more bone turnover, hence more Gd in urine) and intercurrent infection can vary bone removal in both directions.

Read this blog a few times. This deals with the critical aspects of chelation and measurement that pertains to all heavy metals.

Richard Semelka, MD


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