Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

MGCRU
60244
FMASC
90054
Magnesium/Creatinine Ratio, Random, Urine
Clinical Information: Magnesium, along with potassium, is a major intracellular cation. Magnesium
is a cofactor of many enzyme systems. All adenosine triphosphate (ATP)-dependent enzymatic reactions
require magnesium as a cofactor. Approximately 70% of magnesium ions are stored in bone. The
remainder is involved in intermediary metabolic processes; about 70% is present in free form, while the
other 30% is bound to proteins (especially albumin), citrates, phosphate, and other complex formers. The
serum magnesium level is kept constant within very narrow limits. Regulation takes place mainly via the
kidneys, primarily in the ascending loop of Henle. Conditions that interfere with glomerular filtration
result in retention of magnesium and, hence, elevation of serum concentrations. Hypermagnesemia is
found in acute and chronic renal failure, magnesium overload, and magnesium release from the
intracellular space. Mild-to-moderate hypermagnesemia may prolong atrioventricular conduction time.
Magnesium toxicity may result in central nervous system (CNS) depression, cardiac arrest, and
respiratory arrest. Numerous studies have shown a correlation between magnesium deficiency and
changes in calcium-, potassium-, and phosphate-homeostasis, which are associated with cardiac disorders
such as ventricular arrhythmias that cannot be treated by conventional therapy, increased sensitivity to
digoxin, coronary artery spasms, and sudden death. Additional concurrent symptoms include
neuromuscular and neuropsychiatric disorders. Conditions associated with hypomagnesemia include
chronic alcoholism, childhood malnutrition, lactation, malabsorption, acute pancreatitis, hypothyroidism,
chronic glomerulonephritis, aldosteronism, and prolonged intravenous feeding.
Useful For: Assessing the cause of abnormal serum magnesium concentrations Determining whether
the body is receiving adequate nutrition
Interpretation: With normal dietary intake of 200 to 500 mg of magnesium per day, urine excretion is
typically 30 to 210 mg/gm creatinine in children and adults. The remainder of the dietary intake passes
through the gastrointestinal tract and is excreted in the feces. Decreased renal function, such as in
dehydration, diabetic acidosis, or Addison's disease, results in reduced output of magnesium. Poor diet
(alcoholism), malabsorption, and hypoparathyroidism result in low urine magnesium due to low uptake
from the diet. Chronic glomerulonephritis, aldosteronism, and drug therapy (cyclosporine, thiazide
diuretics) enhance excretion, resulting in high output of magnesium.
Reference Values:
0-15 years: 110-210 mg/g creatinine
> or =16 years: 30-100 mg/g creatinine
Clinical References: 1. Fenton TR, Eliasziw M, Lyon AW, et al: Low 5-year stability of
within-patient ion excretion and urine pH in fasting-morning-urine specimens. Nutr Res 2009
May;29(5):320-326 2. Mircetic RN, Dodig S, Raos M, et al: Magnesium concentration in plasma,
leukocytes and urine of children with intermittent asthma. Clin Chim Acta 2001 Oct;312(1-2):197-203
Malaria Antibody Screen (P. falciparum, P. vivax, P. malariae, P.
ovale), IFA
Reference Values:
Reference Range: Pos = > 1:64 Neg 64 - In U.S. citizens (brief exposure) may reflect recent infection; in some areas of the world,
may be maximum titer demonstratable even in clinical cases.
In U.S. citizens with brief exposure to infection, a PLASMODIUM FALCIPARUM titer of =>1:64
may reflect recent infection. Speciation of the infecting malaria parasite is made by using four IFA slides
prepared with P. FALCIPARUM, P. VIVAX, P. MALARIAE and P. OVALE, respectively. Antibody
titers in U.S. citizens rarely persist more than six (6) months after chemotherapeutic cure. Titers in people
with prolonged exposure and in people native to malaria endemic areas may persist for years because of
relapses. Due to the increased volume of diagnostic specimens and to maximize the use of our malaria
slides, we now titrate specimens at dilutions of 1:16 and 1:64. We will report immunofluorescence results
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