Sign in →

Test Code LAB118 Protein, Total, Blood

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Note: This test is also available as part of LAB17 Comprehensive Metabolic Panel (CMP) and LAB20 Hepatic Function Panel. See Common Panel Test Combinations to avoid duplicate requests if needed.

 

Patient Preparation: None

Collection Container/Tube:

Preferred: Mint green-top Lithium Heparin (MNTGRN LiHep) tube

Acceptable: Green samplette/microtainer, plain red-top tube, Gold SST gel tube, or Lavender-top (EDTA) tube

Submission Container/Tube: If specimen is coming from outside facility and collected in a microtainer, plain red-top tube, or lavender-top tube aliquot processed sample into a plastic vial for transport (labeling with specimen type).

Specimen Collection Volume: 1.0 mL (minimum 0.6 mL)

Special Instructions: Avoid prolonged venous stasis when collecting the speicmen. Send to lab promptly.

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 2 hours from receipt in performing lab

Reference Values

Reference Interval: 

Plasma  
<7 days: 4.5-7.0 g/dL
7 days - 1 year: 5.5-7.5 g/dL
≥ 1 year: 6.5-8.5 g/dL                                                  
Serum  
<7 days: 4.2-6.7 g/dL
7 days-1 year: 5.2-7.2 g/dL
>or= 1 year: 6.2-8.2 g/dL

Critical Value: <3.0 g/dL (all ages for plasma and serum)

Critical test results will be automatically called initially and every 168 hours thereafter.

 

Methodology

Colorimetric

Limitations

  • In very rare cases gammopathy, in particular type IgM (Waldenstrom's macroglobulinemia) may cause unreliable results.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge to separate. If specimen is collected in microtainer, plain red-top tube, or lavender-top tube aliquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).

Processed Volume: 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 24 hours
Plasma/Serum (processed) Refrigerated (preferred)   3 days
  Ambient  24 hours
  Frozen  6 months    

NOTE: If specimen is collected and received in a red-top (or SST gel) tube, re-order for "Protein Ser". This is required as serum reference intervals differ from plasma. 

Test Classification and CPT Code

84155

LOINC

2885-2

Last Reviewed

06/2025