Creatinine, Random Urine

Laboratory assay overview

Acylglycines are an important class of metabolites that are used in the diagnosis of several organic acidurias and mitochondrial fatty acid oxidation disorders. This test is intended for the diagnosis and monitoring of several organic acidemias and fatty acid disorders affecting multiple metabolic pathways. Disorders diagnosed by Acylglycines assay: Isovaleric acidemia 3-Methylcrotonyl-Co-A-carboxylase deficiency Short-chain acyl-CoA dehydrogenase(SCAD) deficiency Ethylmalonic Encephalopathy Propionic acidemia Glutaric aciduria type-1, 2 and 3 Medium-chain acyl-CoA dehydrogenase(MCAD) Beta-ketothiolase deficiency 17-Beta-hydroxysteroid dehydrogenase deficiency Isobutyryl-CoA dehydrogenase deficiency Short/branched-chain acyl-CoA dehydrogenase deficiency (SBCADD) The test will also allow physicians to determine dietary compliance or the effectiveness of dietary/cofactor therapy for their patients. It can also be used, alone or in conjunction with other tests, to confirm the findings of a positive expanded newborn screen.

Laboratory assay overview

Amino acid analysis is necessary for the diagnosis of a variety of inborn errors of metabolism. These include, but are not limited to, phenylketonuria, tyrosinemia, citrullinemia, non-ketotic hyperglycinemia, maple syrup urine disease, and homocystinuria. The assay is also key for the continued monitoring of treatment plans for these disorders and useful for assessing nutritional status of patients. Our methodology is highly accurate at very low levels as well as at elevated levels.

Laboratory assay overview

The intended use for this test is as a means of evaluating patients with a suspected inherited disorder of creatine metabolism. The cerebral creatine deficiency syndromes (CCDS), inborn errors of creatine metabolism, include the two creatine biosynthesis disorders (guanidinoacetate methyltransferase [GAMT] deficiency and L-arginine: glycine amidinotransferase [AGAT or GATM] deficiency), and the X-linked creatine transporter [SLC6A8] deficiency. Intellectual disability and seizures are common to all three CCDS. The majority of individuals with GAMT deficiency have a behavior disorder that can include autistic behaviors and self-mutilation; a significant proportion have pyramidal/ extrapyramidal findings. Onset is between the ages of three months and three years. The phenotype of SLC6A8 deficiency in affected males ranges from mild intellectual disability and speech delay to severe intellectual disability, seizures, and behavior disorder, with age at diagnosis ranging from 2 to 66 years. Females heterozygous for SLC6A8 deficiency may have learning and behavior problems.

Laboratory assay overview

This quantitative test may be useful for evaluation of individuals with clinically suspected cystinuria, including those with symptoms of kidney stones or cystine crystals detected in urinalysis [1]. Although 24-hour urine testing is generally preferred for diagnostic evaluation and monitoring of cystinuria [2], random or first-morning void urine collection may be helpful for diagnosis when 24-hour urine collection is not feasible (eg, for young children) [3]. Cystinuria, an autosomal recessive genetic disorder that can cause kidney stones, is characterized by excessive excretion of cystine and dibasic amino acids in the urine. Around 1% to 2% of all kidney stones, and 6% to 8% of kidney stones in children, are caused by cystinuria [1]. Approximately 83% of patients with cystinuria who develop a kidney stone will have a recurrence within 5 years [1]. Common complications of cystinuria include chronic kidney disease and hypertension [1]. This test does not differentiate between free and bound cystine in patients taking cystine-binding thiol drugs [1]. This test alone is not sufficient to predict risk of kidney stones in individuals with cystinuria [1]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Daga S, et al. Urology. 2021;149:70-75. 2. Williams JC Jr, et al. Urolithiasis. 2021;49(1):1-16. 3. Servais A, et al. Kidney Int. 2021;99(1):48-58.

Laboratory assay overview

Methylmalonic Acid (MMA) is useful to diagnose and monitor Vitamin B12 (cobalamin) deficiency, and to diagnose and monitor patients with methylmalonic acidemia.

Quest Diagnostics population reference ranges

Quest Diagnostics calculates these statistical intervals for this specific assay and demographic group, not as universal optimal targets.

Laboratory assay overview

This test is intended for the diagnosis and monitoring of inherited disorders affecting multiple metabolic pathways. Organic acidurias are inherited disorders resulting from a deficient enzyme or transport protein. Although most are autosomal recessive disorders, several are X-linked. The more than 60 described organic acidurias affect many metabolic pathways including amino acid metabolism, lipid metabolism, purine and pyrimidine metabolism, the urea cycle, the Krebs cycle and fatty acid oxidation. These disorders are characterized by a wide variety of symptoms such as lethargy, coma, hypotonia, seizures, ataxia, vomiting, failure to thrive, developmental delay, liver disease, neutropenia, thrombocytopenia, osteomalacia and osteoporosis. Severity of presentation is highly variable as is age of onset, and patients may not present with the most characteristic features. Laboratory results commonly indicate metabolic acidosis, increased anion gap, hyperammonemia, hypoglycemia, lactic acidemia, ketosis, or abnormal lipid patterns. Treatment may be based on dietary restrictions and/or supplementation with cofactors (e.g., riboflavin or cobalamin) or conjugating agents (e.g., carnitine or sodium benzoate); however, there is no effective therapy for some of the disorders. Elevation of one or more organic acids is diagnostic for an organic aciduria; however, elevations should be interpreted in context with clinical findings and/or additional test results. See additional information for a table of selected organic acidurias and associated organic acid elevations. Since many organic acidurias are episodic, the diagnostic efficacy is maximized when the patient is expressing symptoms at the time of specimen collection. The test will be capable of diagnosing over 30 inherited metabolic defects, and will also allow physicians to determine dietary compliance or the effectiveness of dietary/cofactor therapy for their patients. It can also be used, alone or in conjunction with other tests, to confirm the findings of a positive expanded newborn screen.

Laboratory assay overview

This test is intended for the diagnosis and monitoring of inherited disorders affecting multiple metabolic pathways. Organic acidurias are inherited disorders resulting from a deficient enzyme or transport protein. Although most are autosomal recessive disorders, several are X-linked. The more than 60 described organic acidurias affect many metabolic pathways including amino acid metabolism, lipid metabolism, purine and pyrimidine metabolism, the urea cycle, the Krebs cycle and fatty acid oxidation. These disorders are characterized by a wide variety of symptoms such as lethargy, coma, hypotonia, seizures, ataxia, vomiting, failure to thrive, developmental delay, liver disease, neutropenia, thrombocytopenia, osteomalacia and osteoporosis. Severity of presentation is highly variable as is age of onset, and patients may not present with the most characteristic features. Laboratory results commonly indicate metabolic acidosis, increased anion gap, hyperammonemia, hypoglycemia, lactic acidemia, ketosis, or abnormal lipid patterns. Treatment may be based on dietary restrictions and/or supplementation with cofactors (e.g., riboflavin or cobalamin) or conjugating agents (e.g., carnitine or sodium benzoate); however, there is no effective therapy for some of the disorders. Elevation of one or more organic acids is diagnostic for an organic aciduria; however, elevations should be interpreted in context with clinical findings and/or additional test results. See additional information for a table of selected organic acidurias and associated organic acid elevations. Since many organic acidurias are episodic, the diagnostic efficacy is maximized when the patient is expressing symptoms at the time of specimen collection. The test will be capable of diagnosing over 30 inherited metabolic defects, and will also allow physicians to determine dietary compliance or the effectiveness of dietary/cofactor therapy for their patients. It can also be used, alone or in conjunction with other tests, to confirm the findings of a positive expanded newborn screen.

Laboratory assay overview

Hypophosphatasia (HPP) is a rare metabolic bone disease characterized by defective mineralization of bones and teeth through decreased activity of tissue non-specific alkaline phosphatase (TNSALP). Pathogenic variants in the ALPL gene on chromosome 1 lead to HPP, which can be inherited in an autosomal recessive or autosomal dominant fashion depending on the nature of the variant; the dominant form of the disease typically exhibits a mild phenotype. HPP has a range of severity, with the most severe forms presenting in infancy or even prenatally and the mildest forms presenting in adulthood. However, it should be noted that a prenatal benign form of HPP also exists. Depending on the age of onset and/or severity, HPP can be classified as either Perinatal, Infantile, Juvenile, Adult, or as Odontohypophosphatasia. In the most severe perinatal form of the disease, skeletal deformities are present at birth and can also be detected on prenatal ultrasound. The impaired bone mineralization results in skeletal abnormalities including shortening and bowing of the limbs, a narrow chest leading to hypoplastic lungs. Stillbirths are common with this severe phenotype. Most individuals with perinatal HPP did not survive. Infantile HPP presents within the first six months of life with rickets and increased bone fractures. Growth is affected and patients can experience hypercalcemia and nephrocalcinosis. Childhood HPP presents after six months of age; radiographic features are consistent with rickets and premature loss of teeth with intact roots is a characteristic finding. In adults, HPP often presents with recurrent fractures, stress fractures, slow-healing fractures, and bone and joint pain. In the mildest form of the disease, odontohypophosphatasia dental abnormalities are found in the absence of any skeletal manifestations. The severe form of the disease has an incidence of approximately 1:300,000 based on a French study; the prevalence of the milder autosomal dominant form of the disease was predicted to be as high as 1:6370 from the same study. HPP can be diagnosed by decreased activity of serum alkaline phosphatase and increased excretion of the TNSALP substrate phosphoethanolamine (PEA) in urine. Molecular analysis of the ALPL gene can also be used to establish a diagnosis of HPP. There is strong genotype-phenotype correlation. The recombinant enzyme replacement therapy (ERT) was approved by the FDA in 2015 and has been used as first-line therapy in several forms of HPP. PEA urinalysis is used to support a diagnosis of HPP, especially in patients with low alkaline phosphatase, and to monitor ERT. Several studies showed that elevated urine PEA is a specific biomarker for HPP. However, other bone diseases, some endocrine disorders and hypertension can also cause elevated urine PEA.

Quest Diagnostics population reference ranges

Quest Diagnostics calculates these statistical intervals for this specific assay and demographic group, not as universal optimal targets.