> ## Content Index
> Fetch the complete content index at: https://www.pigpen.page/llms.txt
> Use this file to discover other available public pages before exploring further.

# Sapropterin trial, part 2: Baseline testing
- URL: https://www.pigpen.page/sapropterin-trial-part-2-baseline-testing/
- Published: 2023-06-30T10:38:44.000Z
- Updated: 2023-11-30T17:08:16.000Z
- Description: Maintaining this level of control would be a tough ask. But I discovered that, when I thought I had been strict on my diet in the past, I really hadn’t.
- Author: Pauline
- Tags: Low Protein, PKU, #Sapropterin, #Research, #Import 2024-07-21 13:17

Baseline testing is a necessary period of control before starting on sapropterin. It ensures that your blood phe levels have stabilised before starting the medication. Importantly, it gives a baseline against which any response can be easily seen. During baseline testing, my blood spots changed from monthly to weekly. And, I needed to show at least 6 results which were: 

- between 300umol/L and 600umol/L and,
- within 100umol/L of each other

This would give the baseline figure against which the blood phe levels while I was on sapropterin would be tested.

Part one of the Sapropterin Blog series:

[Sapropterin blood genetics test for PKU PhenylketonuriaA year after I went in for blood tests to determine if my PKU would respond, I finally took my first dose of sapropterin.![](https://pigpen.page/content/images/size/w256h256/2019/03/pigpen-logo.png)Pig PenPauline O’Connor![](https://pigpen.page/content/images/2023/05/Polly--head---shoulders.jpg)](https://www.pigpen.page/sapropterin-trial-part-1/)

Click for part one in the series.

### Lessons from Baseline testing

I was ready to start baseline testing in early December, the month of parties and food. While the testing could be delayed until the new year, I had already waited over 40 years for a treatment beyond restricted diet therapy. The desire to start immediately meant strict control over Christmas. Most years I would stick to the diet, but also have quite a few treats; like more potatoes, or extra sweets.

Not this year! Christmas and New Year’s became a time of searching out protein-free treats; including fruit jellies, PKU baking, and lots of exotic fruit. December and January were not easy, but I did learn more about my diet and attitude to it than I had in the past year. Most importantly, I learned that I had never done something quite like this before.

I knew that the control needed to reach the six blood phe levels required for baseline testing would be difficult. When I checked the list of my bloodspot results from the last 30 odd years, I discovered that I’d come close to managing that once in three decades. I knew that maintaining this level of control would be a tough ask. But what I didn’t know was that when I thought I had been strict on my diet in the past, I really hadn’t.

### Blood phe can be too low

The requirement to weigh all my food and record every exchange & supplement across a month gave me the best control I’d ever had. Usually, when I was being strict, I would not *quite* record every exchange. Instead, I’d convince myself that I would remember it. Or that a little extra at supper wouldn’t change things too much. Or I wouldn’t weigh portions and just eyeball the amount.

In the three years running up to the baseline testing, my average levels were 500umol/L. During testing, two days before Christmas, my level was 104umol/L. My lowest blood result ever.

In the first four weeks of baseline testing, my levels were between 300umol/L and 100umol/L. After an initial burst of planning, the organisation to get these levels was not terribly different from before the control period. The focus on my diet actually felt good, as I was doing it with purpose. Physically, I had more energy and my head felt clearer on these lower levels.

That is interesting, and something I want to explore in the future. However, those levels were too low for the baseline trial. Indeed, after my result of 104, the clinic called to check I was okay. It is possible for blood phe levels to be too low, as well as too high.

### Protein allowance increase without sapropterin

I have heard from others who had to increase exchanges during the baseline testing, and before starting on sapropterin. And, like them, I had wondered why. Now, I was experiencing it myself.

The level of control I was showing to get my levels down below 200 consistently, meant there wasn’t enough leeway to show a response to sapropterin when I eventually started the medication. I needed higher levels, so the clinic increased my exchange limit. My phe allowance increased by two exchanges, from 5g of protein every day to 7g. This was a wonder to me, as other people on low exchanges will know.

I was suddenly allowed more daily protein than I’d ever been on in the past. And I hadn’t even tried sapropterin yet. How did that happen? I think the increase in exchanges happened because, in the past, I hadn’t actually been recording my diet properly. This meant I was having those extra 2 exchanges in snacks and extra helpings, but I wasn’t recording them.

Now I had permission from the clinic, so I could have those two exchanges without guilt. As long as I recorded them carefully! The good news is that, whether I respond to sapropterin or not, I should be able to keep those extra two exchanges. As long as I don’t revert to my unintentional ‘no need to record them, she’ll be right’ attitude.

### Reducing hunger on PKU

I started taking (and recording!) the extra two exchanges and noticed a change in my hunger levels immediately. That was interesting, given I had probably been having those two exchanges in an unplanned manner already. I could now plan my food to incorporate those exchanges across the whole day.

Instead of using those two exchanges on unplanned afternoon snacks, or rationalising them as ‘just a little extra’, I spent a cold January having those two extra exchanges planned across the day. Breakfast, lunch, and dinner were now 2 phe each. And the final exchange was held back in case of an unforeseen office biscuit tin, or an oat milk latte with a friend. If I hadn’t used it by then end of the day, I had a small supper.

It might seem like a small change, but the increase in phe at breakfast meant I could last the entire morning without hunger pangs. The same happened in the afternoon, and I soon found I wasn’t having my elevenses and afternoon snacks. The increase in exchanges alone was worth the months of weekly bloodspots and weighing.

### 11 weeks of control before sapropterin

It took me 11 weeks to get a baseline level of six blood tests which were between 300 and 600umol/L, and which were within 100umol/L of each other. It was not easy. I skipped events, pub lunches, evenings out, visits to friend’s places… Basically, I didn’t go anywhere that I could not be sure of the exact content of protein in my food.

However, I finally reached the baseline requirements almost exactly a year after undergoing blood tests for genetic testing. It had taken patience, perseverance, the encouragement of others in the PKU community. But I could finally start on a sapropterin trial.

**Note:** the three years before baseline testing, I had been on 5 exchanges and I thought I had a strict control. Over those 3 years, my average blood phe level was 500umol/L. During the ‘strictly recorded and measured’ 7 exchange regime, my average blood level was 490umol/L. This, and the fact that I knew I was guilty of being a little loose sometimes, is what leads me to believe that I had been having the extra 2 phe previously, and was simply not recording them carefully.

### [Next: the sapropterin trial.](https://www.pigpen.page/sapropterin-trial-part-3-the-trial/)