Reticulocytes, Hct, ESR, Hgb Flashcards
What is the calculation for the reticulocyte count?
- (# of reticulocytes x 100) / 1000 RBC
What are some examples of sources of error in retic counts?
- Anemic or polycythemic
- Mixing appropriately
- Moisture – artifacts are refractile
- Heinz bodies, Howell Jolly and pappenheimer
What is the reference range for reticulocytes in:
- Adults
- Newborns
- Adults: 0.5 – 1.5 – or up to 2.0% in many places
- Newborns: 2.0 – 6.0%
What can cause the following changes in the range of a retic count?
- Decreases
- Increases
- Decreases: suppressed bone marrow production
- Increases: hemolytic anemias, response to therapy
What is an absolute reticulocyte count?
- actual number of reticulocytes in 1 liter or 1 microliter of blood
- What is the calculation for an absolute retic count?
- What is the reference range?
- (Reticulocytes (%) X RBC count (X10^12/L)) / 100
- Reference ranges 25,000 to 75, 000/uL
- When would a corrected retic count be used?
- What is the count correcting?
- Principle this calculation is used for individuals who have a low hematocrit. Retic count will be falsely elevated as there are fewer RBC
- Negates or minimizes the dilutional effect
What is the calculation for a corrected retic count?
- retic % x (patient Hct% / 45)
- What is the Reticulocyte Production Index?
- What is the calculation for it?
- Correction for the Shift reticulocytes in the circulation
- Correction needed because of the presence of shift reticulocytes
- RPI = (reticulocyte (%) X HCT (%)/45) / maturation time
What is the range of BM response for the Reticulocyte Production Index?
- Adequate BM response >3
- Inadequate BM response < 2
What are some of the errors of a manual retic count (4)?
- stain variability
- slide distribution
- statistical sampling error
- interobserver error
Microhematocrit
- Equipment and material
- 2 plain capillary tubes
- Nonabsorbent clay
- Microhematocrit tubes
- Microhematocrit reader
Microhematocrit
- Procedure
- Take two plastic plain tubes since the specimen is EDTA blood
- Seal tube nonabsorbent clay. Hold tube horizontally. Plug should be 4mm long.
- Balance tubes in a hematocrit centrifuge with sealed end facing the outside touching the rubber gasket.
- Tighten the lid of the microhematocrit centrifuge.
- Centrifuge at 10,000 g to 15,000g for 5 minutes. Do not use brake to stop the centrifuge.
- Determine the hematocrit of both tubes. Read the hematocrit using the reader. Do not include the buffy coat.
- Duplicate reading must match up to 1%.
What are the reference ranges for HCT for adult males and females?
- Adult male: 40 – 54%
- Adult female: 35 – 49%
Rule of Three
- Principles
- Calculations
- Principles – visual check for normocytic, normochromic red blood cells
- value of hematocrit should be three times the value of hemoglobin +/- 3
- HGB X 3 = HCT +/- 3 (0.03 L/L)
What are four circumstances when values do not follow the “Rule of Three”?
- Abnormal red cells
- Hemoglobin concentration: hypochromic, microcytic
- If red cells look normal; falsely low hemoglobin or false elevation of hematocrit
- Lipemic specimen: falsely high hemoglobin
Mean Corpuscular Volume (MCV):
- Calculation
- Unit of measurement
- (HCT (%)× 10) / (RBC count (×10^12/L))
- femtoliters
- What is the mean corpuscular hemoglobin (MCH)?
- Unit of measure?
- Av. weight of hemoglobin
- measured in pictograms
What is the calculation for mean corpuscular hemoglobin (MCH)?
- HGB (g/dL)×10 / RBC count (×10^12/L)
Mean corpuscular hemoglobin concentration (MCHC):
- Units of measurement
- Calculation
- g/dL
- HGB (g/dL)×100 / HCT (%)
Reference ranges for:
- MCV
- MHC
- MCHC
- MCV 80 -100fL (<80 fl microcytic, >100fl macrocytic)
- MCH 26 – 32 pg
- MCHC 32 -36 g/dL (<32 hypochromic and >36 g/dL sperocytic shapes)
Erythrocyte Sedimentation Rate:
- Definition
- International reference method
- Distance RBCs fall in an hour (mm/hr)
- International reference method: Westergren method
Erythrocyte Sedimentation Rate:
Reference range
- Males under and over 50 yrs
- Females under and over 50 yrs
- Males 0-15mm (up to age 50)
- Males 0-20mm (over age 50)
- Females 0-20mm (up to age 50)
- Females 0-30mm (over age 50)
Sedimentation Rate:
- Sources of error (3)
- ↑ temperature
- air bubbles
- tube tilting
Sedimentation Rate:
- What can this test indicate?
- NON-SPECIFIC indicator of inflammation or infection
