Author | Luan Jianwei
Unit | Department of Clinical Laboratory, Donggang Hospital of Traditional Chinese Medicine, Liaoning Province
Preface
Uric acid is a heterocyclic compound containing carbon, nitrogen, oxygen, hydrogen, under normal circumstances, the uric acid in the body is about 1200mg, about 600mg is newly generated every day, and 600mg is excreted at the same time, which is in a balanced state. However, if the body produces too much too late to excrete or the uric acid excretion mechanism degenerates, the uric acid retention in the body is too much, when the blood uric acid concentration is too large, resulting in human body fluids becoming acidic, affecting the normal function of human cells, long-term disregard will cause gout. In addition, excessive fatigue or insufficient rest can also lead to relatively slow metabolism and lead to the onset of gout.
With the improvement of people's living standards and lifestyle changes, the prevalence of hyperuricemia (HUA) is increasing. According to the data data, the prevalence of hyperuricemia in Chinese adults is 8.4%, and excessive or excretion of blood uric acid is too much, so that the supersaturated urate concentration in the blood is deposited in the kidneys [1], and all the uric acid in the blood is filtered from the glomeruli, so when the renal function is reduced, it is often accompanied by an increase in serum uric acid.
Case after
Remember that it was the morning of January 17, 2021, the Nephrology Department sent a set of biochemical tests, as usual, we numbered, centrifuged and machine tested the specimen, and when the instrument detected the results, I found that the patient's kidney function results were abnormal, but the uric acid result was 59.6 μmol/L. This is different from our impression that when the kidney function is reduced, it is often accompanied by an increase in serum uric acid, which is really puzzling. If this patient is really so low in uric acid there must be something special about it. In order to be responsible for the patient, and for the accuracy of the results, I must find out the reason.
So I gradually searched for the cause according to the department's abnormal result handling procedures: the specimen was qualified without hemolysis, chylomicron, jaundice, etc., and the possibility of blood collection on the infusion side was ruled out, and the indoor quality control results of the biochemical instrument were good and the reagents and dilutions were sufficient. Refer to the WS/T420-2013 document to develop a performance verification scheme to verify the precision (in-batch precision and inter-batch precision), accuracy, linear range and reference interval [2].
After many times of review, the results are still like this, and there is no special change in the detection curve, which is relatively normal.
Case studies
The director often tells us that we should communicate with the clinician as soon as possible when encountering special circumstances. So, I dialed the phone of the nephrologist, and after preliminary communication, the patient was stage III of nephropathy, the state was acceptable, this time it was a routine hospital admission, and there were no other emergencies.
After hanging up the phone, I thought carefully for a while, I remember reading an article written by the test god before, if the patient's body contains special immunoglobulins, special immunoglobulins will react with uric acid detection reagents, which will cause abnormalities in uric acid test results, and the reaction curve will also change abnormally. In this case, there was no obvious abnormality in the patient's uric acid detection curve, indicating that the abnormal result of this time can exclude the possibility of special substance interference.
I have also seen some materials before, diuretics, calcineurin inhibitors, antituberculosis drugs, chemotherapy drugs, etc. can increase the concentration of uric acid in the patient's blood, so will there be drugs to reduce the concentration of uric acid in the patient's blood? The patient has kidney disease itself, will it be a drug effect?
Thinking of this, I checked several commonly used drugs in our country that can reduce uric acid, including: benzbromarone, febuxtron, allopurinol and so on. The efficacy of benzbromarone is to promote tubular excretion of uric acid, so it is generally not recommended for patients with poor renal function. The effect of drugs such as non-bustax and allopurinol is to inhibit the formation of uric acid, in which non-bustaxal treatment of uric kidney disease can not only reduce the patient's blood uric acid, but also play a role in protecting the kidneys [3].
Thinking of this, I dialed the doctor's phone again, and after communication, I learned that the patient was a patient with three stages of kidney disease and needed to take a variety of drugs for treatment for a long time, including the uric acid-lowering drug nonbutex.
At this moment, I suddenly became enlightened, it may be due to the influence of uric acid-lowering drugs, so that the uric acid content in the patient's body is reduced, so that the results of the test are also correspondingly reduced. After listening to my analysis, the doctor agreed with me, and the test results were approved by the clinician.
On August 19, 2021, Corey colleagues found a similar case of abnormal renal function results and relatively low uric acid results, because of her previous experience, I instructed her to check according to the process of formulating abnormal results in the department, and at the same time to communicate with clinicians in time to see if patients take similar uric acid-lowering drugs. Later, after feedback, patients did have long-term use of drugs such as febustach.
Case summary
Long-term use of uric acid-lowering drugs can gradually reduce the uric acid content in the patient's body, so that the results of the test will be correspondingly reduced. The views expressed in this article may be more limited, the accuracy of uric acid result detection is affected by many factors and drugs, it may not only be a drug, a special substance, there may be a variety of factors together, which requires us to continue to find and summarize in our daily work, here to give you a brick and jade.
Expert reviews
Guo Xianhong, chief technician of the Department of Clinical Laboratory of Donggang City Hospital of Traditional Chinese Medicine in Liaoning Province
Being a qualified tester is not an easy task, and we must continue to work hard. First of all, we must communicate with clinicians in a timely manner, and we also need to continue to learn and think in our daily work, and do our own work with love and a responsible attitude towards patients.
bibliography
He Bangyou,Cheng Xiaoxia. Professor Cheng Xiaoxia's experience in the treatment of uric acid kidney disease[J].Chinese Journal of Nephrology of Integrated Traditional And Western Medicine,2020, v.21(07):67-68.
Xu Changbin, Li Yi, Hu Jiuhe, et al. Performance verification of CFA protein kit in Beckman AU680[J].Health Vision, 2020(6):1.
He Zhihong, Yi Jianwei, Yuan Feng, et al. Observation of the clinical efficacy of febuxex in the treatment of uric acid kidney disease[J]. 2021(2016-9):1260-1262.
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Note: This article is an original contribution and does not represent the new media views of laboratory medicine. When reprinting, please indicate the source and the name and unit of the original author.
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Editor: Shaoqing Xu Reviewer: Chen Xueli