Continuing on the lactate concentration measurements...
My mentor, Dr. Mitchell, Andrew, and I ran triple controlled solution tests to the Lactate Plus meter accuracy. While the results were within 10% difference, our measurements from last testing were odd and became a difficulty for us to figure out why the results went wrong. We followed the instructions and tested Andrew's right hand fingers again for the resting period. I was another subject to test my lactate concentration, too. However, we attained measurements within a wide range of 1.3mmol to 2.5mmol and 0.9mmol to 3.2mmol of lactate concentration, which were disappointing and frustrating. To check the body conditions and if it's just that lactate is challenging to measure, we used glucose meter to take samples for Andrew and I. The outcomes had about 5% difference, suggesting that the glucose meter was accurate and the body conditions were stable. Consequently, we started researching on other methodologies of lactate concentration testing. Lactate Pro was considered the most popular due to its reliability and affordability, but it was only available outside of the US. Some other analyzer were expensive such as Analox GL5 that costs up to 10,000 dollars. With the budget restriction, we were experiencing a hard time to decide if we should just accept the big fluctuation of the Lactate Plus meter or to purchase other equipment.
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Dr. Mitchell, my mentor, introduced his graduate student Andrew Clifford to be our first subject for lactate threshold measuring experiment.
Main Component: Our protocol is to follow what is considered the best time interval (4 min) for each speed pace, and the pace depends on the subject's fitness. 1. Measure lactate concentration of the subject when standing. Warm up at about 4 mph for 6 min. 2. Run on the treadmill at 5 mph for 4 min. 3. Get 30 seconds of rest while measuring lactate concentration of the subject. 4. Increase the intensity of pace by 1 mph, which is now 6 mph for 4 min. 5. Repeat step 3 and 4 until the subject has six data points. 6. Graph the data points and use a smooth, curve line to determine the lactate threshold. Difficulties: We faced the inconsistency problem again today, with the subject having 2.0, 1.0, 4.6, 4.7, 1.8, 1.0, 1.9, 1.1 mmol of lactate while standing. The discrepancy is hard to avoid, so we tried to minimize the exposure of test trips to air, reduce the time for each trial, and checking the cleanness of the poking sites. Due to the lack of time and insufficient test strips, we did not start official treadmill testing. We hope to catch up to our plan next time. I started collecting my own lactate concentration data samples to be further examined for exercise use and also to solve the accuracy issue.
This time, I used alcohol swab to thoroughly clean the poking site to prevent inaccuracy. The data collection began with my index finger as the poking site, and I was measuring the lactate concentration by myself while writing down the data. Thus, it was difficult for me to clean my hands, poke my own finger, get enough blood drop to fill the well on the strip, and to record the data at first, but with more practices and trials, I became familiar to conducting the measurement by myself only. I tested my index finger with seven trials of similar area and obtained the results of 1.6, 1.1, 1.1, 0.4, 0.5, 1.1, and 0.7. My mentor and I thought that the discrepancy was still to large to be accurate, so we called the technical support of the lactate plus meter company to seek for help. The technician suggested that we should not test the same finger over time, instead, different fingers would reveal the actual lactate concentration. Also, check the lactate plus meter with control solution every time before we run the experiment. Therefore, we tried three other trials of my middle finger, ring finger, and my pinky. The data are relatively close and accurate: 1.0, 0.8, 0.8. WHY USE DIFFERENT FINGERS? I did not ask the technician the reasons to use different fingers for lactate concentration measurement (partially because she did not really know how to explain), but I was curious about the cause. One of the reasons that came to my mind was that capillaries on fingers were damaged when I poked my finger for the first time, and the exposure to air and hypothetically contaminated site would affect the test strip measurement. TIPS for measuring lactate concentration: Test the lactate plus meter with control solution before collecting data. Use different fingers for measurement. Clean the sites thoroughly with alcohol swab and soap, dry with paper towel. Stay warm. My fist internship officially started today at The Sage Colleges in Troy.
My mentor, Dr. Mitchell, first introduced the goal of the project--investigating the correlation of VO2max and lactate threshold, and we began to collect lactate concentration samples. Equipment: The equipment we used included lactate plus meter, lactate test strips, two control solutions, lancet holder and lancets. Steps: We followed the manual instruction to collect data samples, but we did not prepare alcohol swab that was supposed to be used to clean the site. 1. Remove the protective cover and place a lancet into the lancet holder. Remember to change the lancet every time the subject is changed. 2. Adjust the depth setting and wash the poking site thoroughly with soap. 3. Dry the poking site with paper towel, stay warm, and massage the finger with it pointing downward to stimulate the blood flow. 4. Turn on the lactate plus meter and place a lactate test strip into the meter, be ready to get sample tested. 5. Run a test with the control solution to examine the accuracy of the lactate plus meter. 6. Use the lancet device to poke at a site of the finger, wipe the first drop of blood out since it may be contaminated, and gently massage the finger to get a second drop of blood. 7. Put the strip well close to the site and let the blood fill the well. 8. The meter will start beeping, meaning that it is processing, and wait for 13 seconds for the result. Accuracy and Problems: We wanted to double-check the accuracy, so we tested the same finger again and again, expecting a similar measurement of lactate concentration. However, the outcomes were not close at all with a wide range from 3.5, 2.1, 2.9, 2.3 to 1.7. We changed the finger sites from left hand index finger and ring finger to right hand index finger and ring finger as well, so we considered that as another variable affecting the data. Insufficient cleaning of not using alcohol swab might be another factor, so did the chilly cold lab temperature (57 degrees F) Conclusion: To resolve the accuracy issue, we decided to use the same finger of the same hand every time, get warmed up completely, and to clean the fingers with alcohol swab. |
AuthorClass of 2019 at Emma Willard School. Archives
May 2018
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