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HelpTest Code LAB387 Cystine Quantitative, Urine Random
Clinical System Name
Cystine, U Rand Qnt
Description
Quantitation of cystine by ion exchange chromatography
Sample Requirements
Specimen: Urine
Container(s): Sterile Screw-Capped Container
Preferred Vol: 5.0 mL
Minimum Vol: 1.0 mL
Processing Instructions
Reject due to:
Spin:N
Aliquot:Y
Temp:-20 C
Storage location: -20 C BCG Box
SCHRMC/Off-site collection: Mix urine well and freeze a maximum10 mL aliquote. Ship frozen.
Stability
| Temperature | Time |
|---|---|
| Room temp | ≤ 24hr |
| Refrigerated | < 24 hrs |
| Frozen | 1 month |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Biochemical Genetics
Phone Number: 206-987-2216
Synonyms
Cystine U
Availability
| STAT | Performed | TAT |
|---|---|---|
| N | M-F | 5 days |
Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.
Methodology
Method: Ion exchange chromatography with post column derivatization
Analytical Volume: 1.0 mL
Limitations:
CPT Codes
82131
Requisition
Biochemical Genetics Requisition
On the requisition include clinical information needed for appropriate interpretation. (Age, gender, diet (e.g. TPN therapy), drug therapy and family history)
Reference Ranges
| Newborn | 2 mo-1 year | 1 year-12 year | 12 year-adult |
| 60-660 umol/g creatinine | 60-425 umol/g creatinine | 60-180 umol/g creatinine | 50-180 umol/g creatinine |
Unit change to umol/g creatinine (previously mg cys/g creatinine) effective 10/25/22.
To convert to mg cystine/ g creatinine, multiply the mcmol cys/g creatinine result by 0.2403 (see conversion breakdown below).
X mcmol cys * (1 mol)_____ * (240.3 g cys) * (1000 mg cys) = X * 0.2403 mg cys
g creatinine (10^6 mcmol) (1 mol) ( 1 g) g creatinine