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HelpTest Code LAB753 Hemoglobin and Hematocrit
Performing Laboratory
St. Louis Children's Hospital Laboratory - Hematology
Specimen Requirements
Patient Preparation: None
Collection Container/Tube:
Preferred: Lavender-top (EDTA) tube
Acceptable: Lavender-top (EDTA) microtainer
Submission Container/Tube: If sending from outside facility, do not transfer specimen to different container. Keep specimen in original collection container to send.
Specimen Collection Volume:
| Vacutainer: | 2.0 mL (minimum 0.5 mL) whole blood |
| microtainer: | full tube (minimum 0.3 mL) whole blood |
Special Instructions: Immediately invert tube gently 8-10 times after collection to ensure proper mixing of blood and anticoagulant (this will avoid specimen clotting). Do not overfill tube.
Sample Rejection
Mislabled or unlabeled specimens
Clotted specimens
Logistics
Test Availability: Monday-Sunday
Cut-off time: None, performed as received
Turnaround Time: Same Day; 30 minutes from receipt in lab
Reference Values
Reference Interval:
| AGE: | HEMOGLOBIN | HEMATOCRIT |
| <3 days | 14.5-22.5 g/dL | 45.0-66.0% |
| 3 days-2 weeks: | 12.5-20.5 g/dL | 39.0-63.0% |
| 2 weeks-1 month: | 10.0-18.0 g/dL | 31.0-55.0% |
| 1 month-6 months: | 9.0-14.0 g/dL | 28.0-42.0% |
| 6 months-2 years: | 10.5-13.5 g/dL | 33.0-39.0% |
| 2-6 years: | 11.5-13.5 g/dL | 34.0-40.0% |
| 6-12 years: | 11.5-15.5 g/dL | 35.0-45.0% |
| FEMALE ≥ 12 years: | 11.9-15.5 g/dL | 35.6-45.5% |
| MALE ≥ 12 years: | 13.0-17.5 g/dL | 38.9-50.3% |
Critical Value:
| Hemoglobin | |
| <12 years: | <7.0 g/dL |
| 12-18 years: | <6.0 g/dL |
| ≥ 18 years: | <6.5 g/dL OR >or =20.0 g/dL |
No established critical values for Hematocrit results
Critical test results will be automatically called back initially and every 72 hours thereafter with the exception of outpatient and ED patients, those will be called everytime.
Methodology
Photometrics and cumulative pulse height detection
Limitations
- NA
Additional Information
FOR SLCH CORE LABORATORY USE ONLY
Lab Processing Instructions: DO NOT SPIN. give specimen directly to hematology bench
Processed Volume: minimum 0.5 mL whole blood in vacutainer tube or min 0.3 mL in microtainer
Analyte Stability:
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood (unprocessed) | Ambient | 24 hours |
| Refrigerated | 24 hours | |
| Frozen | not acceptable |
Test Classification and CPT Code
85018
LOINC
Hgb: 718-7
Hct: 4544-3
Last Reviewed
07/2025