Ordering Recommendation

Monitor cyanide exposure.

Quantitative Colorimetry
Sun, Tue, Fri
1-5 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Timing of specimen collection: Dependent on time of exposure - test upon presentation to hospital. 
Green (sodium or lithium heparin). Also acceptable: Lavender (EDTA) or pink (K2EDTA or K3EDTA). 
Specimen Preparation
Do not freeze. Transport 4 mL whole blood in original collection container. (Min: 3 mL) Also acceptable: Transfer specimen to an ARUP Standard Transport Tube. 
Storage/Transport Temperature
Room temperature. 
Unacceptable Conditions
Serum or plasma. Frozen or refrigerated specimens. Clotted or hemolyzed specimens. 
Ambient: 72 hours (if tightly capped); Refrigerated: Unacceptable; Frozen: Unacceptable 
Reference Interval
Effective February 19, 2013
Non-smokersLess than 20 µg/dL
SmokersLess than 40 µg/dL
Toxic LevelGreater than 100 µg/dL

Interpretive Data
Cyanide poisoning can cause hypoxia, dizziness, weakness and mental and motor impairment. Elevated cyanide concentrations rarely indicate toxicity for patients on nitroprusside therapy. Thiocyanate should be monitored in patients on nitroprusside therapy for potential toxicity.

No laboratory test is available to assess cyanide toxicity in patients on nitroprusside therapy. However, thiocyanate toxicity may occur with long-term nitroprusside use (longer than 7-14 days with normal renal function and 3-6 days with renal impairment at greater than 2 µg/kg/min infusion rates). Thiocyanate levels may be monitored on an every other day basis to assess potential thiocyanate toxicity and to indicate possible adjustments in dosage.  Refer to Thiocyanate, Serum or Plasma (ARUP test code 2011575).
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  • Amygdalin
  • Hydrocyanic acid
  • Laetrile