Type: Z

Test 398

SuperUser Account — Tue, 16 Sep 2008 21:45:07 GMT

Test: Zinc, Plasma or Serum
Number: 001800
CPT: 84630
Synonyms: Zn, Serum
Specimen: Plasma (preferred) or serum
Volume: 2 mL
Minimum Volume: 0.6 mL
Container: Royal blue-top (EDTA or heparin) tube or red-top tube.
Collection: Separate serum from cells within 45 minutes of collection and transfer to a plastic transport tube. Plasma may be separated immediately and transfer to a plastic transport tube for shipment to the laboratory.
Storage Instructions: Maintain specimen at room temperature.
Causes for Rejection: Gel-barrier tube; unspun red-top tube
Reference Interval: Environmental exposure: 70-150 μg/dL
Use: Monitor exposure to zinc; evaluate suspected nutritional inadequacy, especially in enteral or parental nutrition, critically ill or burn patients; cases of diabetes or delayed wound healing; growth retardation; follow therapy, for example when higher intravenous zinc doses are used to balance excessive ongoing GI losses in long-term total parenteral nutrition; follow oral zinc therapy in Wilson disease; confirm acrodermatitis enteropathica and follow therapy
Limitations: Levels may be low in fever, sepsis, estrogen therapy, stress, or myocardial infarction, reflecting mobilization from serum to the liver by interleukin. Levels are usually low in uremia with normal tissue levels. Levels may be high in familial hyperzincemia without toxicity or high zinc stores.
Methodology: Atomic absorption spectrometry (AAS); inductively-coupled plasma-mass spectrometry (ICP-MS)
Additional Information: Chronic oral zinc supplementation interferes with copper absorption and may precipitate copper deficiency. Albumin is the primary zinc binding protein: zinc levels should be interpreted with awareness of serum albumin level.
References:

Alfrey AC, “Essential Trace Elements,” The Kidney: Physiology and Pathophysiology, 2nd ed, Seldin DW and Giebisch G, eds, New York, NY: Raven Press, Ltd, 1992, 2993-3003.

Ruz M, Cavan KR, Bettger WJ, et al, “Development of a Dietary Model for the Study of Mild Zinc Deficiency in Humans and Evaluation of Some Biochemical and Functional Indices of Zinc Status,” Am J Clin Nutr, 1991, 53(5):1295-303.

Test 574

SuperUser Account — Tue, 16 Sep 2008 21:48:51 GMT

Test: Zinc, Urine
Number: 003434
CPT: 82570; 84630
Synonyms: Zn, Urine
Test Includes: Creatinine, urine; zinc, urine; zinc:creatinine ratio; zinc, urine (24-hour)
Special Instructions: If 24-hour urine is submitted, then request form must state 24-hour collection volume. Do not use preservative. Preservatives used for routine analysis may contain mercuric oxide (ie, Stabilur), which interferes with all metal testing. If both urinalysis and metal testing are ordered, please submit a separate urine specimen (containing no additive) for the metal testing.
Specimen: Urine (24-hour or random)
Volume: 5 mL
Minimum Volume: 1.7 mL
Container: Plastic urine container, no preservative
Collection: Optional protocol: Instruct the patient to void at 8 AM and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning). Screw the lid on securely.
Storage Instructions: Maintain specimen at room temperature.
Reference Interval: Environmental exposure: 100-900 μg/g creatinine,¹ 150-1200 μg/24 hours
Use: Evaluate zinc exposure; evaluate low serum zinc levels; evaluate compliance in oral zinc therapy of Wilson disease.² Low urine zinc levels in the presence of depressed serum zinc tends to confirm zinc deficiency.
Limitations: Zinc deficiency is usually accompanied by decreased urine zinc excretion. Zinc deficiency, however, may be in part due to excess urine losses, especially in cirrhosis, hemolytic anemias, sickle cell disease, alcoholism, diabetes, or chronic renal diseases.
Methodology: Inductively-coupled plasma-mass spectrometry (ICP-MS)
Additional Information: Zinc poisoning through inhalation of zinc oxide fumes or dust often produces symptoms of respiratory tract irritation, chest pain and cough, fatigue, headache, nausea, fever, and muscle pain.³ Zinc is utilized as an alloying agent in brass and other metals, as well as in metal plating. Zinc chloride is often produced in the chemical smoke generators that are employed in industry. Zinc chloride is also used in soldering fluxes and wood preservatives.
Footnotes:

Lauwerys RR and Hoet P, Industrial Chemical Exposure: Guidelines for Biological Monitoring, 2nd ed, Boca Raton, FL: Lewis Publishers, 1993, 293.
Milanino R, Marrella M, Moretti U, et al, “Oral Zinc Sulphate as Primary Therapeutic Intervention in A Child With Wilson Disease,” Eur J Pediatr, 1989, 148(7):654-5.
Baselt RC and Cravey RH, Disposition of Toxic Drugs and Chemicals in Man, 4th ed, Chemical Toxicology Institute, 1995

Test 1103

SuperUser Account — Tue, 16 Sep 2008 22:06:29 GMT

Test: Zonisamide (Zonegran®), Serum
Number: 007915
CPT: 82542
Synonyms: Zonegran®
Special Instructions: Refrigerate at 2°C to 8°C if specimen is not tested immediately.
Specimen: Serum or plasma
Volume: 1.2 mL
Minimum Volume: 0.4 mL (Note: This volume does not allow for repeat testing.)
Container: Red-top tube or lavender-top (EDTA) tube
Collection: Serum should be separated from cells within 45 minutes of collection and transferred to a plastic transport tube. Plasma may be separated immediately and transferred to a plastic transport tube for shipment to the laboratory. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.

Trough: Immediately prior to next dose. Steady-state levels are reached within 5-15 days in patients on zonisamide monotherapy.

Storage Instructions: Refrigerate at 2°C to 8°C if specimen is not tested immediately.
Causes for Rejection: Use of gel-barrier tube; hemolysis; nonseparated serum or plasma specimen
Use: Monitor drug levels for optimal therapy
Limitations: Zonisamide is contraindicated in patients who have demonstrated hypersensitivity to sulfonamides or zonisamide. Consideration should be given to discontinuing zonisamide in patients who develop an otherwise unexplained rash. If the drug is discontinued, patients should be observed frequently.
Methodology: Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Additional Information: Zonisamide is an antiepileptic drug belonging to the sulfonamide class and is chemically unrelated to other antiepileptic drugs. While the exact mechanism of action is unknown, anticonvulsant activity may be mediated by action at sodium and calcium channels. This action may result in stabilizing neuronal membranes and suppressing neuronal hypersynchronizations.¹ Preliminary studies on smaller population groups has indicated possible other uses for zonisamide in intractable neuropathic pain syndromes² and refractory migraine headaches.³

Zonisamide is excreted primarily in urine as the parent drug and glucuronide of the metabolite 2-sulfamoylacetyl phenol. Metabolism of zonisamide is mediated by the P450 isozyme CYP3A4 and to a lesser extent by CYP2D6.⁴ The drug was rapidly absorbed orally following 200-400 mg doses in volunteers. Peak plasma concentrations were 2-5 μg/mL and occurred in 2-6 hours. Food does not effect the overall bioavailability, but delays time to maximum concentration until 4-6 hours. Zonisamide extensively binds to erythrocytes, resulting in an eightfold higher concentration in red blood cells than in plasma. The pharmacokinetics of zonisamide are dose proportional in the range of 200-400 mg.¹ Time to steady state is from 5-15 days with an elimination half-life of 63-69 hours in volunteers receiving no other medication.⁴ The half-life however, is reduced by the co-medicated P450 inducers phenytoin and carbamazepine. The half-life of zonisamide is reduced to a mean of 27.1 hours when the former is co-administered and to a mean of 36.4 hours with co-administration of the latter.⁵

Footnotes:

Duncan L, et al, 2005 Mosby´s Drug Consult, 15th ed, Elsevier Health Sciences, 2005.
Hasegawa H, “Utilization of Zonisamide in Patients With Chronic Pain or Epilepsy Refractory to Other Treatments: A Retrospective, Open Label, Uncontrolled Study in a VA Hospital,” Curr Med Res Opin, 2004, 20(5):577-80.
Drake ME Jr, Greathouse NI, Renner JB, et al, “Open-Label Zonisamide for Refractory Migraine,” Clin Neuropharmacol, 2004, 27(6):278-80.
Leppik IE, “Three New Drugs for Epilepsy: Levetiracetam, Oxcarbazepine, and Zonisamide,” J Child Neurol, 2002, 17:S53-7.
Ojemann LM, Shastri RA, Wilenski AJ, et al, “Comparative Pharmacokinetics of Zonisamide (CI-912) in Epileptic Patients on Carbamazepine or Phenytoin Monotherapy,” Ther Drug Monit, 1986, 8(3):293-6

References:

Asconape JJ, “Some Common Issues in the Use of Antiepileptic Drugs,” Semin Neurol, 2002, 22(1):27-39.

Johannessen SI, Battino D, Berry DJ, et al, “Therapeutic Drug Monitoring of the Newer Antiepileptic Drugs,” Ther Drug Monit, 2003, 25(3):347-63.

Miura H, “Developmental and Therapeutic Pharmacology of Antiepileptic Drugs,” Epilepsia, 2000, 41(Suppl 9):2-6.

Test 1733

SuperUser Account — Tue, 16 Sep 2008 22:37:10 GMT

Test: Zucchini
Number: 060001
CPT: 86003
Specimen: Serum
Volume: 0.2 mL
Container: Red-stopper tube or gel-barrier tube
Storage Instructions: Refrigerate
Methodology: Quantitative allergen-specific IgE test

Test 4430

SuperUser Account — Wed, 17 Sep 2008 02:51:49 GMT

Test: ZAP-70 in B-CLL
Number: 489000
CPT: 88184; 88185 (x2); 88187
Special Instructions: Testing referred to US Labs, Brentwood, Tenn (403040)
Collect specimen Monday through Thursday only. Specimen must be received at US Labs in Brentwood, Tenn, within 48 hours of collection. Please state date and time of collection on the test request form.
Specimen: Peripheral blood (preferred) or bone marrow
Volume: Peripheral blood: 7 mL whole blood in green-top (heparin) tube or 1 lavender-top (EDTA) tube, store and ship ambient.
Bone marrow: 2 - 3 mL of marrow in green-top (heparin) tube. Ship ambient.
Container: Green-top (heparin) tube or lavender-top (EDTA) tube
Storage Instructions: Store and ship according to specimen type received
Methodology: Flow cytometry