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HelpTest Code LAB387 Cystine Quantitative, Urine Random
Clinical System Name
Cystine, U Rand Qnt
Synonyms
Cystine U
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 |
Availability
| STAT | Performed | TAT |
|---|---|---|
| N | M-F | 5 days |
Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Biochemical Genetics
Phone Number: 206-987-2216
CPT Codes
82131
Methodology
Method: Ion exchange chromatography with post column derivatization
Analytical Volume: 1.0 mL
Limitations:
Description
Quantitation of cystine by ion exchange chromatography
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