Understanding Microalbumin (urine Albumin-Creatinine Ratio – uACR) on the OAp™ Organic Acids Profile
Albumin is one of the main proteins found in the blood. It maintains oncotic pressure and provides nutrition to renal tubulars (kidneys). Albumin is not normally found in the urine. Urinary albumin is also called microalbumin.
Microalbumin, as with all markers on the OAp, is normalized to creatinine and thus represents a ratio. Measuring 24-hr urine is the gold-standard method for detecting microalbuminuria, but measuring the urine albumin-to-creatinine ratio (uACR) in spot urine samples is also acceptable. First morning voids are more reliable than random spot urine samples to assess microalbuminuria. Albuminuria has been defined as a urine albumin-to-creatinine ratio (uACR) of 30 mg/mg or higher.1
Elevated Microalbumin
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Microalbuminuria does have some benign causes. Temporary dysfunction of the filtration barrier can occur under certain conditions leading to temporary increases in microalbumin:
- Fever and/or dehydration
- Urinary Tract Infections (UTI)
- After vigorous exercise: check frequency/intensity
- In smokers: air pollution implicated
- Higher muscle mass
- Sample contamination: emphasize careful clean-catch specimen
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Due to its close association with adverse health conditions, microalbuminuria should be further evaluated for more serious and chronic conditions.2 The National Kidney Foundation states that kidney disease usually does not show any symptoms until the later stages of the disease – so it is important to have a uACR test (or OAp) at least once a year if you have any of these risk factors:
- Diabetes
- Hypertension (high blood pressure)
- Cardiovascular disease (history of heart attack or stroke)
- Heart failure
- Family history of kidney disease, kidney failure, or dialysis
- Increased body weight (especially if your body mass index or BMI is over 30)
- Smoking or other use of tobacco products
- Over the age of 60
Additional Markers to Review:
Since microalbuminuria can be associated with impaired glucose processing, other markers on the OAp report that may give further insight to metabolic function include, Glucose, Lactic acid, D-Lactic acid, Beta-hydroxybutyric acid, and Glyceric acid. Observational studies have identified elevated circulating branched-chain amino acids, phenylalanine, tyrosine and glutamic acid early in metabolic dysfunctions and glucose processing.
Urine Microalbumin on OAp™
The majority of clients looking at urine organic acids will have a microalbumin result of less than detection limit. Less than detection limit (<dl) is the most common result.
Further questions and testing may be needed in patients who have a microalbumin level above 30.
Literature:
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In a cohort study of US adults (n=23,697), high-normal UACR was associated with a significantly increased risk of all-cause mortality. The association was more pronounced in adults with poor cardiovascular health status. The findings highlight the importance of risk management for early kidney dysfunction. Participants with poor cardiovascular health status and high-normal UACR had the highest risk of all-cause mortality.3
- Several studies have shown that achieving a higher Cardiovascular Health Score (CVH) score based on American Heart Association’s Life’s Essential 8 correlated with a lower risk of premature cardiovascular disease (CVD), CVD mortality, and all-cause mortality. The Essential 8 include, diet, exercise, nicotine exposure, sleep, BMI, blood lipids, glucose and pressure.4
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In a post hoc analysis (n=10,171), an elevated UACR was associated with a higher risk of major adverse cardiovascular events (MACEs) and total mortality in patients with type 2 diabetes mellitus (T2DM), even when it falls within the normal range.5
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Vascular aging involves endothelial dysfunction, increased arterial diameter, wall thickness, and stiffness. Endothelial dysfunction is likely to be involved in the initiation and development of microalbuminuria. This is initially reversible but becomes fixed with increasing vascular structural changes.6
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Microalbuminuria is a marker for generalized vascular dysfunction. Increased risk for cardiovascular morbidity and mortality begins with albumin excretion rates that are well within normal limits.7
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Screening for early diabetic kidney disease is best done with annual spot urine albumin/creatinine ratio testing, and diagnosis is confirmed by repeated elevation in urinary microalbumin excretion.8
About the OAp™ - Organic Acids Profile
The OAp provides powerful insights into nutrient status as well as energy metabolism, mitochondrial function, fat metabolism, toxic exposure, neurotransmitter balance, microbial metabolites, and more. Findings from the OAp can inform personalized recommendations for improving metabolic health. Elevate patient care and order the OAp - Organic Acids Profile today!
Author Betsy Redmond, Ph.D., MMSc, RDN
Dr. Redmond has 30 years experience in nutrition with a focus on functional laboratory assessment, research and application. She is a registered dietitian-nutritionist, with a Masters' degree in clinical nutrition from Emory University and a PhD in nutrition from the University of Georgia. Dr. Redmond is the past president of Dietitians in Integrative and Functional Medicine and the recipient of the Excellence in Practice award...
The opinions expressed in this presentation are the author's own. Information is provided for informational purposes only and is not meant to be a substitute for personal advice provided by a doctor or other qualified health care professional. Patients should not use the information contained herein for diagnosing a health or fitness problem or disease. Patients should always consult with a doctor or other health care professional for medical advice or information about diagnosis and treatment.
References
- Wang L, Xu X, Zhang M, Hu C, Zhang X, Li C, Nie S, Huang Z, Zhao Z, Hou FF, Zhou M. Prevalence of Chronic Kidney Disease in China: Results From the Sixth China Chronic Disease and Risk Factor Surveillance. JAMA Intern Med. 2023 Apr 1;183(4):298-310.2. Seegmiller JC, Bachmann LM. Urine Albumin Measurements in Clinical Diagnostics. Clin Chem. 2024 Feb 7;70(2):382-391.3. Mahemuti N, Zou J, Liu C, Xiao Z, Liang F, Yang X. Urinary Albumin-to-Creatinine Ratio in Normal Range, Cardiovascular Health, and All-Cause Mortality. JAMA Netw Open. 2023 Dec 1;6(12):e2348333. 4. Sun J, Li Y, Zhao M, Yu X, Zhang C, Magnussen CG, Xi B. Association of the American Heart Association's new "Life's Essential 8" with all-cause and cardiovascular disease-specific mortality: prospective cohort study. BMC Med. 2023 Mar 29;21(1):116.5. Zeng C, Liu M, Zhang Y, Deng S, Xin Y, Hu X. Association of Urine Albumin to Creatinine Ratio With Cardiovascular Outcomes in Patients With Type 2 Diabetes Mellitus. J Clin Endocrinol Metab. 2024 Mar 15;109(4):1080-1093.6. Abdelhafiz, A.H., S. Ahmed, and M. El Nahas, Microalbuminuria: marker or maker of cardiovascular disease. Nephron Exp Nephrol, 2011. 119 Suppl 1: p. e6-10. 7. Karalliedde J, Viberti G. Microalbuminuria and cardiovascular risk. Am J Hypertens. 2004 Oct;17(10):986-93.8. McGrath, K. and R. Edi, Diabetic Kidney Disease: Diagnosis, Treatment, and Prevention. Am Fam Physician, 2019. 99(12): p. 751-759.