Clin. DX LAB: Exam 2 M.O Questions

My own questions from studying & Post Labs

What is the Reference Range of WBC count for adults? (include units)

5.0-10.0 × 10³/ mm³

What is the reference range of RBC count for adult women? (include units)

4.0-5.5 × 10^6/mm³

What is the reference range for RBC counts for adult males? (include units)

4.5-6.0 × 10^6/mm³

What is the area for RBC count calculations?

0.2 mm²

What diluent is used for WBC counts? To what ratio?

Turk’s solution; 1:20

What objective lens is used to visualize the hemocytometer for manual WBC counts?

40x

The hemoglobin molecule consists of which components?

Four heme groups, each attached to a global chain (two alpha, two beta in HbA)

What reagent is used for hemoglobin measuring?

Drabkin’s reagent

What type of hemoglobin cannot be converted to cyanmethemoglobin by Drabkin’s reagent?

Sulfhemoglobin

What is the reference range for Hematocrit of an adult male?

40-52%

What is the reference range for Hematocrit for an adult female?

37-45%

What type of individual has the highest hematocrit?

Healthy newborns

What is the reference range for hemoglobin in adult males? (include units)

13.5-17.5 g/dL

What is the reference range for hemoglobin in adult females? (include units)

12.5- 15.5 g/dL

What happens to hematocrit when there is excess EDTA in an undefiled lavender tube?

Red blood cells shrink (crenate) leading to a falsely decreased hematocrit

What is the rule for correlating hemoglobin and hematocrit?

Hematocrit should be approximately 3 times the hemoglobin

How do calculate MCV? What units is it measured in?

hematocrit x 10 / RBC counts; femtoliters

How to calculate MCH? What units?

hemoglobin x 10/ RBC count; picograms

How to calculate MCHC; What units?

Hemoglobin/ hematocrit x 100; g/dL

What is the reference range for Mean Cell Volume (MCV)?

80-96 femtoLiters

What is the reference range for Mean Cell Hemoglobin (MCH)?

27- 33 Picograms

What is the reference range for Mean Cell Hemoglobin Concentration (MCHC)?

33-36 g/dL

What is it called when MCH is low?

Hypochromia

What is it called when MCHC is high? When low?

There are spherocytes; Hypochromic

What anemia presents as Microcytic and Hypochromic?

Iron deficiency anemia

What anemia presents as normocytic and normochromic?

Chronic disease anemia

What anemia presents as macrocytic?

pernicious anemia

What are 3 pieces of patient information that is required on a laboratory requisition?

Patient name, DOB, and Medical Record #

What is in the red top tube?

nothing/ clot activator coating

What is in the Green top tube?

Heparin

What is in the light blue top tube?

Sodium citrate

What is in the grey top tube?

Sodium fluoride

What is the order of priority for veins during venipuncture?

Median cubital, cephalic, basilic

What are naturally occurring antibodies called?

IgM

What are immune/unexpected antibodies?

Antibodies produced as a result of immunizations caused by pregnancy or transfusion

What immunoglobulin can cross the placenta? What antigen is it associated with?

IgG and it is associated with antigen D

Drawing a lavender tube before a chemistry tube may result in:

Falsely elevated potassium

What tube is used for a CBC?

Lavender

What tube is used for PT/PTT testing?

Light blue

A routine chemistry test is usually collected in what tube?

SST or PST light green

What color tube should lactic acid be collected in?

Grey

What angle should the needle be inserted in for venipuncture?

15-30 degrees

If there is no blood flow after insertion, one possible cause is?

Needle passing through the vein

What can titer provide information about? (2)

The amount of antibody in the plasma or the strength of the antigen present on the RBCs

What is the diluent in antibody titration?

Saline

How is titer determined?

By taking the reciprocal of the highest dilution that produces 1+ agglutination

What are internal controls?

Materials with known values that are tested alongside patient samples to ensure the system is functioning properly within the lab

What are external controls?

Materials provided by an external source (like proficiency testing agencies) to evaluate the laboratories performance in comparison to other labs

What is the center line on the Levey-Jennings chart?

The mean

What are Westgaurd rules?

Used to interpret QC data from a Levey-Jennings chart

How is the coefficient of variation (CV%) calculated?

(SD/ mean) x 100

What is the 1-2s rule of Westgard QC? What course of action should be taken?

When a single data point exceeds 2 SD from the mean; this should be taken as a warning sign indicating a need for closing monitoring

What is the 1-3s rule of Westgard QC? What course of action should be taken?

A single data point exceeds 3 SD from the mean; this signals likely error and requires immediate investigation

What is the 2-2s rule of Westgard QC? What does this suggest?

Two consecutive data points exceed 2 SD from the mean; This suggests a systemic error and prompt action should be taken

Define random error; What are the possible causes? What action do you take?

Unpredictable fluctuations in QC results; could be caused by procedural error or electrical fluctuations; You should repeat the QC test, check pipette calibration, and ensure proper reagent mixing

Define systemic error; What are the possible causes? What action do you take?

A consistency bias in QC results either high or low; possible causes include instrument calibration drift, reagent deterioration, or consisting pipetting error; To correct this, recalibrate the instrument, check reagent expiration date, and verify sample handling

Define Drift over time Levey-Jennings Plot; What are the possible causes? What action do you take?

Gradual or sudden change in QC values; Can be caused by reagent lot change, instrument aging, environmental factors; To fix perform a lot-to-lot comparison, recalibrate instrument, check maintenance logs

What are some things that a cause error in a hemoglobin measurement that are pathological? (4)

Lipemic samples, increased WBC levels, Presence of HgB C or HgB S, Increase protein levels

What is the order of draw?

Blood culture, light blue, red/gold (SST/ RST), Green, Lavender, White, Grey

What tube is used for glucose?

Grey