UCSF Clinical Laboratories Test Directory

Ordering

Available Stat

Yes (always run STAT)

Performing Lab

Parnassus Chemistry

Mission Bay Chemistry
Hyde Chemistry
Stanyan Chemistry

Performed

Test available 24 hours per day 7 days per week

Methodology

Glutamate Dehydrogenase

Reported

1 hour

Additional Information

Fasting sample recommended.

NOTE: Ammonia cannot be 'added-on' to a previously tested sample

Specimens should be sampled from free flowing blood without the use of tourniquets or heel/finger sticks. False positive elevations of ammonia can be caused by many factors including use of capillary samples or by delay between sampling and centrifugation (Clinical Biochemistry 40:531-535, 2007).

Eltrombopag can cause absorbance errors in this ammonia assay at concentrations >100 ug/mL.

Synonyms

NH3
ICE

Collection

Sample Type

Heparinized plasma

Label Abbreviation

NH3

Collect

Light Green top (on ice)

Amount to Collect

2 mL blood

Preferred Volume

1 mL plasma

Minimum Volume

0.7 mL plasma

Remarks

Fasting sample recommended. Pre-chill tube. Deliver to lab immediately on ice.

Specimens should be sampled from free flowing blood without the use of tourniquets or heel/finger sticks.

NOTE: Ammonia cannot be 'added-on' to a previously tested sample

Use plasma collected by standard venipuncture techniques. As erythrocytes contain ammonia levels approximately three times that of plasma, hemolyzed samples may result in significant interference.

Acceptable anticoagulants are lithium heparin (with or without gel barrier), sodium heparin, and EDTA. Do not use ammonium heparin.

NOTE: Rapid separation of plasma from blood cells is critical for obtaining reliable results. The standard recommendation is no more than 15 minutes from sample collection to the start of centrifugation. Timing is especially critical for patients with liver disease. Delays exceeding 15 minutes have been shown to increase ammonia concentration even at 0°C. Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

Stability (from collection to initiation)

Sample should be transported to the lab on ice immediately after draw and the plasma separation from cells should be completed within less than 15 minutes of the blood draw. Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

If the plasma cannot be analyzed immediately, it is stable on ice or in the refrigerator for 2 hours and 3 hours at -20°C.

Unacceptable Conditions

If sample is NOT delivered on ice or processed rapidly enough then immediately transport sample to the testing section for analysis. Inform them the specimen was NOT received on ice or NOT processed rapidly enough and a note should be attached to the result that gets reported.

Processing

Test Code

NH3

Performing Lab

Parnassus Chemistry

Mission Bay Chemistry
Hyde Chemistry
Stanyan Chemistry

Specimen Preparation

Centrifuge the cold sample as quickly as possible and separate the plasma from blood cells according to the specimen collection tube manufacturer's instructions. Ensure centrifugation is adequate to remove platelets.

NOTE: Rapid separation of plasma from blood cells is critical for obtaining reliable results. The standard recommendation is no more than 15 minutes from sample collection to the start of centrifugation. Timing is especially critical for patients with liver disease. Delays exceeding 15 minutes have been shown to increase ammonia concentration even at 0°C.

Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

If the test is ordered routine or at Mt. Zion, collect the specimen and centrifuge within 15 minutes. Aliquot and freeze the plasma at -20°C immediately and send to Moffitt/Long via STAT courier.

Preferred Volume

1 mL plasma

Minimum Volume

0.7 mL plasma

Unacceptable Conditions

If sample is NOT delivered on ice or processed rapidly enough then immediately transport sample to the testing section for analysis. Inform them the specimen was NOT received on ice or NOT processed rapidly enough and a note should be attached to the result that gets reported.

Stability (from collection to initiation)

Sample should be transported to the lab on ice immediately after draw and the plasma separation from cells should be completed within less than 15 minutes of the blood draw. Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

If the plasma cannot be analyzed immediately, it is stable on ice or in the refrigerator for 2 hours and 3 hours at -20°C.

Result Interpretation

Units

µmol/L

Reference Interval

Age	µmol/L
0-14 days	21-95
15 days - 6 years	16-68
>6 years	18-72

UCSF Clinical Lab verified the adult reference range stated in the Abbott Ammonia package insert (July 2017) by running 20 male and 20 femal lab volunteers.

Pediatric reference ranges adapted from ARUP Laboratories (May 2019).

Newborn reference range adopted from Maranda et al., Clinical Biochemistry 40:531-535, 2007.

Critical Values

>150 µmol/L for patients less than 18 years of age

Additional Information

Fasting sample recommended.

NOTE: Ammonia cannot be 'added-on' to a previously tested sample

Specimens should be sampled from free flowing blood without the use of tourniquets or heel/finger sticks. False positive elevations of ammonia can be caused by many factors including use of capillary samples or by delay between sampling and centrifugation (Clinical Biochemistry 40:531-535, 2007).

Eltrombopag can cause absorbance errors in this ammonia assay at concentrations >100 ug/mL.

Administrative

CPT Codes

82140

LOINC Codes

22763-7

Complete View

Available Stat

Yes (always run STAT)

Test Code

NH3

Performing Lab

Parnassus Chemistry

Mission Bay Chemistry
Hyde Chemistry
Stanyan Chemistry

Performed

Test available 24 hours per day 7 days per week

Methodology

Glutamate Dehydrogenase

Remarks

Fasting sample recommended. Pre-chill tube. Deliver to lab immediately on ice.

Specimens should be sampled from free flowing blood without the use of tourniquets or heel/finger sticks.

NOTE: Ammonia cannot be 'added-on' to a previously tested sample

Use plasma collected by standard venipuncture techniques. As erythrocytes contain ammonia levels approximately three times that of plasma, hemolyzed samples may result in significant interference.

Acceptable anticoagulants are lithium heparin (with or without gel barrier), sodium heparin, and EDTA. Do not use ammonium heparin.

NOTE: Rapid separation of plasma from blood cells is critical for obtaining reliable results. The standard recommendation is no more than 15 minutes from sample collection to the start of centrifugation. Timing is especially critical for patients with liver disease. Delays exceeding 15 minutes have been shown to increase ammonia concentration even at 0°C. Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

Collect

Light Green top (on ice)

Amount to Collect

2 mL blood

Sample Type

Heparinized plasma

Preferred Volume

1 mL plasma

Minimum Volume

0.7 mL plasma

Unacceptable Conditions

If sample is NOT delivered on ice or processed rapidly enough then immediately transport sample to the testing section for analysis. Inform them the specimen was NOT received on ice or NOT processed rapidly enough and a note should be attached to the result that gets reported.

Specimen Preparation

Centrifuge the cold sample as quickly as possible and separate the plasma from blood cells according to the specimen collection tube manufacturer's instructions. Ensure centrifugation is adequate to remove platelets.

NOTE: Rapid separation of plasma from blood cells is critical for obtaining reliable results. The standard recommendation is no more than 15 minutes from sample collection to the start of centrifugation. Timing is especially critical for patients with liver disease. Delays exceeding 15 minutes have been shown to increase ammonia concentration even at 0°C.

Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

If the test is ordered routine or at Mt. Zion, collect the specimen and centrifuge within 15 minutes. Aliquot and freeze the plasma at -20°C immediately and send to Moffitt/Long via STAT courier.

Units

µmol/L

Reference Interval

Age	µmol/L
0-14 days	21-95
15 days - 6 years	16-68
>6 years	18-72

UCSF Clinical Lab verified the adult reference range stated in the Abbott Ammonia package insert (July 2017) by running 20 male and 20 femal lab volunteers.

Pediatric reference ranges adapted from ARUP Laboratories (May 2019).

Newborn reference range adopted from Maranda et al., Clinical Biochemistry 40:531-535, 2007.

Critical Values

>150 µmol/L for patients less than 18 years of age

Synonyms

NH3
ICE

Stability (from collection to initiation)

Sample should be transported to the lab on ice immediately after draw and the plasma separation from cells should be completed within less than 15 minutes of the blood draw. Once the plasma sample is obtained, it should be maintained on ice or refrigerated and analyzed immediately.

If the plasma cannot be analyzed immediately, it is stable on ice or in the refrigerator for 2 hours and 3 hours at -20°C.

Reported

1 hour

Additional Information

Fasting sample recommended.

NOTE: Ammonia cannot be 'added-on' to a previously tested sample

Specimens should be sampled from free flowing blood without the use of tourniquets or heel/finger sticks. False positive elevations of ammonia can be caused by many factors including use of capillary samples or by delay between sampling and centrifugation (Clinical Biochemistry 40:531-535, 2007).

Eltrombopag can cause absorbance errors in this ammonia assay at concentrations >100 ug/mL.

CPT Codes

82140

LOINC Codes

22763-7