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

NITU
8586
NMDCS
61516
urea nitrogen: too insensitive for calculating nitrogen balance studies in surgical clinical nutrition. J
Parenter Enteral Nutr 1991;15:189-193
Nitrogen, Total, Urine
Clinical Information: Nitrogen is a key component of proteins. During protein catabolism
(proteolysis), nitrogen is excreted in the urine and feces. Protein catabolism may be increased after
stress (eg, physical trauma, surgery, infections, burns). "Nitrogen balance" is the difference between the
amount of nitrogen ingested and the amount excreted. A patient who is in negative nitrogen balance is
using muscle protein to meet the metabolic requirements of the body and is, therefore, in a catabolic
state.
Useful For: Assessing nutritional status (protein malnutrition), evaluating protein catabolism, and
determining nitrogen balance, when used in conjunction with 24-hour fecal nitrogen measurement
Interpretation: Twenty-four hour urinary nitrogen excretion levels within the normal range are
indicative of adequate nutrition. Slightly abnormal excretion rates may be a result of moderate stress or
complications such as infection or trauma. Significantly abnormal excretion rates may be associated
with severe stress due to multiple trauma, head injury, sepsis, or extensive burns. The goal with therapy
for a depleted person is a positive nitrogen balance of 4 g nitrogen/24 hours to 6 g nitrogen/24 hours.
Reference Values:
or =16 years: 4-20 g/24 hours
Clinical References: 1. Phinney SD: The assessment of protein nutrition in the hospitalized
patient. Clin Lab Med 1981;1:767-774 2. Veldee MS: Nutritional assessment, therapy, and monitoring.
In Tietz Textbook of Clinical Chemistry. 3rd edition. Edited by CA Burtis, ER Ashwood. Philadelphia,
WB Saunders Company, 1999, pp 1385-1386 3. Konstantinides FN, Kostantinides NN, Li JC, et al:
Urinary urea nitrogen: too insensitive for calculating nitrogen balance studies in surgical clinical
nutrition. J Parenter Enteral Nutr 1991;15:189-193
NMDA-Receptor Antibody by CBA, Serum
Clinical Information: Patients with NMDA-receptor antibody (targeting the GluN1 [NR1] subunit
of this ionotropic glutamate receptor) have a fairly stereotyped neurological disorder, as described by
Dalmau and colleagues. This disorder often develops in several stages. Prodromal symptoms include
headache, fever, nausea, vomiting, diarrhea, or upper respiratory tract symptoms. Shortly afterwards,
patients develop psychiatric symptoms and many initially come to the attention of psychiatrists.
Anxiety, insomnia, fear, delusions, mania, and paranoia frequently occur; drug-induced psychosis may
be suspected. Other behavioral changes include social withdrawal and stereotyped behavior. Amnesia
and an unusual language disorder (noncortical aphasia) are common. The behavioral changes in children
may be less specific and include temper tantrums and hyperactivity. Neurological disorders including
seizures and dystonia are frequent, and may be the presenting symptom. After these initial symptoms, in
both adults and children, decreased responsiveness ensues. Movement disorders include
oro-lingual-facial dyskinesias, generalized chorea, oculogyric crisis, dystonia, and rigidity. Autonomic
manifestations include hyperthermia, tachycardia, hypersalivation, hypertension, bradycardia,
hypotension, urinary incontinence, and erectile dysfunction. Hypoventilation may necessitate extended
ventilatory support (often months). Dissociative responses similar to those caused by NMDA-receptor
antagonists (eg, phencyclidine or ketamine) have been observed (eg, resisting eye opening despite lack
of response to painful stimuli). The female:male ratio of patients is about 8:1. Overall, ovarian teratoma
is encountered in approximately 50% of affected women. The most useful screening tests include
magnetic resonance imaging (MRI) of pelvis, computed tomography (CT) scan, and pelvic and
transvaginal ultrasound. The detection of teratoma is dependent on age and ethnic background; the
younger the patient, the less likely that teratoma will be detected; black women are more likely to have
teratoma than other ethnic groups. Only 2% have a neoplasm other than ovarian teratoma. Neoplasms
documented in women include breast adenocarcinoma, ovarian neuroendocrine tumors, sex cord
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