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# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Homocysteine, Total, Plasma (HCYSP)
Test Code: HCYSPSO
Synonyms/Keywords
Methionine Load
Useful For
Elevated levels of plasma homocysteine (Hcyst) have been reported to be associated with high risk of cardiovascular diseases. The assay can assist in diagnosis and treatment of patients suspected of having hyperhomocysteinemia and homocystinuria. ​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Fasting Preferred 12 Hours; Not Required ​EDTA Plasma ​Lavender Top Tube (LTT) ​Plasma Preparation Tube (PPT), Citrate, Sodium Flouride, Heparin ​0.4 mL ​0.15 mL
Collection Processing Instructions

Per Mayo

1. Immediately place specimen on wet ice.

2. Spin down and separate plasma from cells within 4 hours of draw. A refrigerated centrifuge is not required if 4-hour time restraint is met.

3. Alternatively, if blood is not immediately placed on ice, plasma must be removed from cells within 1 hour of draw. A refrigerated centrifuge is not required if 1-hour time restraint is met.

Specimen Stability Information
Specimen Type Temperature Time
​Plasma EDTA ​ ​Refrigerate (preferred) ​2 weeks
​Frozen ​8 months
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinical Laboratories ​Monday through Saturday ​2 days ​Tandem Mass Spectometry
Reference Lab
Reference Range Information
Performing Location Reference Range
​Mayo Clinical Laboratories ​<=13 mcmol/L
Interpretation

Homocysteine concentrations >13 mcmol/ L are considered abnormal in patients evaluated for suspected nutritional deficiencies (B12, folate) and inborn errors of metabolism. Measurement of methylmalonic acid (MMA) distinguishes between B12 (cobalamin) and folate deficiencies, as MMA is only elevated in B12 deficiency. Response to dietary treatment can be evaluated by monitoring plasma homocysteine concentrations over time.

Homocysteine concentrations< or =10 mcmol/L are desirable when utilized for cardiovascular risk.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83090 ​1 ​Homocysteine, Total, Plasma
Synonyms/Keywords
Methionine Load
Ordering Applications
Ordering Application Description
​Clinical Order Manager ​​Homocysteine, Total, Plasma (HCYSP)
​Cerner ​Homocysteine, Total, Plasma (HCYSP)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Fasting Preferred 12 Hours; Not Required ​EDTA Plasma ​Lavender Top Tube (LTT) ​Plasma Preparation Tube (PPT), Citrate, Sodium Flouride, Heparin ​0.4 mL ​0.15 mL
Collection Processing Instructions

Per Mayo

1. Immediately place specimen on wet ice.

2. Spin down and separate plasma from cells within 4 hours of draw. A refrigerated centrifuge is not required if 4-hour time restraint is met.

3. Alternatively, if blood is not immediately placed on ice, plasma must be removed from cells within 1 hour of draw. A refrigerated centrifuge is not required if 1-hour time restraint is met.

Specimen Stability Information
Specimen Type Temperature Time
​Plasma EDTA ​ ​Refrigerate (preferred) ​2 weeks
​Frozen ​8 months
Useful For
Elevated levels of plasma homocysteine (Hcyst) have been reported to be associated with high risk of cardiovascular diseases. The assay can assist in diagnosis and treatment of patients suspected of having hyperhomocysteinemia and homocystinuria. ​
Reference Range Information
Performing Location Reference Range
​Mayo Clinical Laboratories ​<=13 mcmol/L
Interpretation

Homocysteine concentrations >13 mcmol/ L are considered abnormal in patients evaluated for suspected nutritional deficiencies (B12, folate) and inborn errors of metabolism. Measurement of methylmalonic acid (MMA) distinguishes between B12 (cobalamin) and folate deficiencies, as MMA is only elevated in B12 deficiency. Response to dietary treatment can be evaluated by monitoring plasma homocysteine concentrations over time.

Homocysteine concentrations< or =10 mcmol/L are desirable when utilized for cardiovascular risk.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinical Laboratories ​Monday through Saturday ​2 days ​Tandem Mass Spectometry
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83090 ​1 ​Homocysteine, Total, Plasma
For most current information refer to the Marshfield Laboratory online reference manual.