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Hematocrit, automated (Complete View)

Item Value
Test name Hematocrit, automated
Test Update Information
Approval req'd? No
Available Stat? Yes
Utilization Guidelines
Test code HCT, HCTM, CBC, CBCD, ORHT, LBGH
Test group Hct
Performed by Parnassus & Mt. Zion Hematology
Sendout?
In House Availability Test available 24 hours per day 7 days per week
Method Calculation from MCV and RBC Count (Automated) or Centrifugation (Manual) or Conductance (iStat)
Patient Preparation
Collection Instructions
Container type Lavender top
Amount to Collect 1 mL blood
Sample type EDTA whole blood
Preferred volume 1 mL blood
Min. Volume 250 uL (microtainer sample) See notes.
UCSF Rejection Criteria
Processing notes
Ref Lab Rejection Criteria
Units %
Normal range
0-7 days 45-67%
8-14 days 42-66%
2-4 weeks 39-63%
1-2 months 31-55%
2-3 months 28-42%
3-6 months 29-41%
6-24 months 33-39%
2-5 years 34-40%
5-12 years 35-45%
Male 12-15 years 37-49%
Male 15-18 years 38-49%
Male > 18 years 41-53%
Female > 12 years 36-46%
Critical value
Synonyms Hct; Crit; PCV; Packed cell volume
Stability
Turn around times STAT 1 hour, Routine 4 hours
Reflex?
Additional information Also part of CBC & CBC w/differential

Reference ranges are also dependent upon the intensity of chronic exposure to high altitudes or to tobacco smoke, as well as to the duration of pregnancy. A manual assay will be performed whenever accurate results cannot be obtained on an automated instrument because of some intrinsic abnormality of the specimen, such as the presence of cold agglutinins.

For technical reasons related to plasma trapping between the centrifuged RBCS, manual results are usually 1-2% higher than results by automated methods.

Conductance (e.g. iStat) method may yield spurious results in patients with high volume crystalloid infusion (particularly patients on bypass pump) or other plasma protein derangements. Conductance values may not compare well with calculated Hct results.

Capillary tubes for spun hematocrits require only 100 µL vs 250 µL for a microtainer, but they are leak-prone, fragile, hazardous to handle, less informative than a CBC and-because they are imprecise-should be run in duplicate, diminishing any benefit of requiring less blood volume. We discourage their use but will accept them for processing. Two capillaries should be submitted in a labeled tube to minimize breakage during transport, and should be accompanied by a requisition on which "SPUN HCT" is written next to the box checked for a CBC
CPT coding
Medical Necessity? Yes. Click here for more information
LOINC code
LDT or Mod FDA?
Include for internal use?
Last Updated 11/30/2012 12:49:07 PM
Entry Number 437
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