Lab Medicine

Incidence

The number of NEW cases of a disease that develop in a population in a specific time period.

Prevalence

Proportion of a particular population affected by a medical condition at a specific time.

incidence

the number of new cases of diabetes in a new year would be called the

Prevalence

The population living with diabetes would be the

Sensitivity

The proportion of persons with disease in whom the test is positive.

Specificity

The ability of a test to detect a disease in a true positive person

Specificity

The proportion of persons without a disease that the test will be negative

specificity

The chance that a test will be a true negative in individuals that do not have a disease

TP / (TP+ TN)

Formula for sensitivity

TN / (FP + TN)

Formula for specificity

Positive predictive value

Percentage of patients with a positive test who truly have the disease

PPV= TP / TP + FP

Forumula for PPV

NPV = TN / TN + FN

Forumla for NPV

Screening Test

Used to detect a potential health problem or disease that doesnt yet have signs or symptoms ( or that is early in development)

Diagnostic Test

Test used to confirm diseases

sensitivity

Screening test must have a high _

2

Reference range is within how many SD’s

95%

2 SD’s account for what portion of a population

Critical result flag

Results that are in the life threatening range. May be truly abnormal or the result of a problem with the sample

Delta checks

Represents the difference between a patient’s current result and the previous result.

hemoglobin

Main part of the red blood cell that carries oxygen

Hematocrit

Ratio of the volume of erythrocytes to that of the whole blood

Hematocrit, hemoglobin

____ _, should be three times that of,_ ___

hemoglobin

Hb stands for

hematocrit

Hct stands for

Hb

New borns have an elevated level of ____ (abbreviation)

Hb

Females have lower levels of __ (ab) due to menses and lower testosterone

Mean corpuscular volume

MCV stands for

MCV

Mean volume of a RBC

Macrocytic

Increased MCV is defined as

Normocytic

Normal MCV is defined as

microcytic

Decreased MCV is defined as

Mean corpuscular hemoglobin

MCH stands for

MCH

Contents of Hb in the average RBC

Mean corpuscular Hemoglobin concentration

MCHC stands for

MCHC

Average concentration of Hb in a given volume of packed RBC’s

Red cell distribution width

RDW stands for

RDW

Measures the RBC size variation

increased

RDW is only signifiant if

Iron def

A high RDW is associated with ____

Hypochromic

Too little MCH/ MCHC

Normal

If a RBC has a central pallor of 1/3 of diameter of cell, it is considered

microcytosis

Low MCV is called

Hypochromia

Low MCH is called

Dilutional

Plasma volume can cause anemia due to what effect?

Iron Def

Most common cause of microcytic anemia

microcytic

Red blood cells are smaller than normal are called

hypochromic

When greater than 1/3 of diameter is clear, it is called

Hemolysis or bone marrow not working

Two causes of normocytic anemia

retic count

Test used to see how well the body is responding to anemia

Hemolysis

A high retic count greater than 3% suggest

underproduction

Low retic count less than 3% suggest

macrocytosis

If RBC’s lack central pallor, it is called

chronic alcoholism

Macrocytes are associated with

Megaloblastic anemia

Macrocytosis is associated with

megaloblastic

b 12 or and or folic acid def is associated with

Macrocytosis

The appearance of macro-ovalocytes is associated with

Reticulocytes

Newly released erythrocytes that become mature RBC’s in 24 hours

Reticulocytes

Detected in peripheral blood with supravital stain

Reticulocytes

What does a supravital stain detect?

increased RBC, Hb, HCT

Erythrocytosis is defined as

erythrocytosis

Increased red cell mass due to increased production

erythrocytosis

Chronic hypoxemia, blood doping and EPO from a tumor can all causes

polychromatophilia

RBC’s that are even younger than reticulocytes

[HCT/45] X retic count

Corrected retic count formula