Lab Medicine Basics

Question 1

When would WBC be elevated?

Answer 1

Increased in:
Infections
Inflammatory diseases
Autoimmune Systemic disease: SLE, RA
Leukemia
Emotional, physical stress (“demargination”)

Question 2

When would WBC be depressed?

Answer 2

Low in:
Bone Marrow failure: Sepsis., malignancies
Collagen Vascular Disease
Medications- antimetabolites, barbiturates, anticonvulsants, antithyroid

Question 3

When would Hemoglobin be increased? (6)

Answer 3

Increased in:
Severe dehydration
COPD
Polycythemia, Erythrocytosis
Shock
CHF
High altitude

Question 4

When would Hemoglobin be decreased? (6)

Answer 4

Decreased in:
Hemolytic reactions
Acute or Chronic blood loss
Pregnancy
Leukemia
Drugs
Hyperthyroidism, severe

Question 5

Hematocrit usually follows Hemoglobin - examples?

Answer 5

Hemoglobin will typically be = hematocrit/3.

Ex: Hb 11, Hct 33

Ex: HB 5, Hct 15

Question 6

When would platelets be increased? (4)

Answer 6

Increased in:
Essential Thrombocytosis
Myeproliferative states
Hemolysis
Acute inflammatory states as an acute phase reactant

Question 7

When would platelets be decreased? (6)

Answer 7

Decreased in:
ITP
HIT
Aplastic anemia
Uremia
Hypersplenism
Bone Marrow Failure related to infection: sepsis

Question 8

Low platelets signs and symptoms?

Answer 8

Easy bruising
Epistaxis
Hematuria
menorrhagia

Question 9

Basic Metabolic Panel: Sodium is high

why?

Answer 9

Hypernatremia: Dehydration (loss of water), Cushings syndrome, Hyperaldosteronism, Advanced age, Pregnancy

Question 10

Basic Metabolic Panel: Sodium is low

why?

Answer 10

Hyponatremia: diarrhea, vomiting, HF, Liver Failure (dilutional), SIADH

Question 11

Basic Metabolic Panel: Potassium is low

Answer 11

Low: vomiting, diarrhea, metabolic alkalosis, diuretics, Decreased intake, renal dysfunction

Question 12

Basic Metabolic Panel: Potassium is high

why?

Answer 12

High: AKI, CKD, Metabolic Acidosis, Drugs like ACEI and ARBS

Question 13

Basic Metabolic Panel: Chloride is low

why?

Answer 13

Low: vomiting, excess sweating, SIADH, mineralocorticoid excess

Question 14

Basic Metabolic Panel: Chloride is high

why?

Answer 14

High: diarrhea, ATN, mineralocorticoid deficiency, drugs

Question 15

Basic Metabolic Panel: BUN is high

why?

Answer 15

High: Acute GN, PCKD, GI bleeding (breakdown of hemoglobin in gut), chronic nephritis, CKD

Question 16

Basic Metabolic Panel: BUN is low

why?

Answer 16

Low: malnutrition, malabsorption, nephrotic syndrome, overhydration

Question 17

Basic Metabolic Panel: CR is low

why?

Answer 17

Low creatinine: Muscle wasting

Question 18

Basic Metabolic Panel: CR is high

why?

Answer 18

creatinine High: Renal dysfunction, Shock, dehydration, HF, increased body mass

Question 19

Anion gap

Answer 19

Anion Gap refers to concentration of unmeasured anions in blood such as protein, phosphate, sulphate, organic acids

AG = Na – (Cl + HCO3). Usual normal range
Can use serum BMP to estimate.

Question 20

What causes increased anion gap?

Answer 20

Increased: uremia, lactic acidosis, ketoacidosis, DKA, Rhabo, alcohol abuse, Drugs

*mnemonic* GOLD MARK.

Glycols (ethylene and propylene), Oxoproline, L-lactate, D-lactate, Methanol, Aspirin, Renal failure, and Ketoacidosis

Question 21

What causes decreased anion gap?

Answer 21

Low: cirrhosis, nephrotic syndrome, hemorrhage, lithium intoxication

Question 22

Serum iron test

Answer 22

Iron can be measured in serum (preferred) or plasma. The test measures circulating iron, most of which is bound to the transport protein transferrin.

Question 23

If Serum iron is low, why?

Answer 23

in iron deficiency as well as in anemia of chronic disease/anemia of inflammation (ACD/AI).

By itself, low serum iron is not diagnostic of any condition but must be evaluated in light of other tests such as transferrin saturation and ferritin.

Question 24

Serum transferrin

Answer 24

Transferrin is a circulating transport protein for iron.

Question 25

Why would serum transferrin be increased? decreased?

Answer 25

increased in iron deficiency decreased in ACD

Question 26

Transferrin saturation – Transferrin saturation (TSAT)

Answer 26

TSAT is the ratio of serum iron to TIBC: (serum iron ÷ TIBC x 100).

Question 27

In iron deficiency, Fe is high/low? TIBC is increased/decreased? transferrin saturation is high/low?

Answer 27

In iron deficiency, iron is reduced and TIBC is increased, resulting in a lower transferrin saturation. •Normal values are in the range of 25 to 45 percent

Question 28

Serum ferritin

Answer 28

Ferritin is a circulating iron storage protein that is increased in proportion to body iron stores. A very low ferritin level is diagnostic of iron deficiency

Question 29

High TSH, Low free T4 and T3 = dx?

Answer 29

Hypothyroidism The TSH is trying to stimulate more hormone production, but it is not working! If there were more hormone in the system, there would be feedback to the anterior pituitary saying, “We’re good, no need to put out more stimulating hormone!”

Question 30

A 65-year-old woman with worsening dyspnea on exertion, fatigue, dizziness, and palpitations. She is found to have conjunctival pallor and guiacpositive stools. DDx?

Answer 30

Unstable angina Congestive Heart Failure Hypothyroidism Atrial fibrillation **Anemia**

Question 31

A 65-year-old woman with worsening dyspnea on exertion, fatigue, dizziness, and palpitations. She is found to have conjunctival pallor and guiacpositive stools. How would we work this patient up?

Answer 31

* CBC -anemia * ECG - A-fib, CHF, New onset unstable angina * Cardiac enzymes - unstable angina * BNP (Brain natureticpeptide)/CXR - CHF, pulmdisease * PT & PTT- coagulation

Question 32

How to evaluate cell appearance?

Answer 32

Peripheral smear

Question 33

How to determine the type of anemia?

Answer 33

Iron studies, VitB-12, folic acid levels

Question 34

How to investigate the source of GI blood loss?

Answer 34

GI consult for possible EGD and colonoscopy

Question 35

Weight loss, lymphadenopathy, and coagulopathy may be an indication of non-gastrointestinal malignancies, such as...?

Answer 35

leukemias or lymphomas

Question 36

Younger patients with anemia, consider...

Answer 36

sickle cell disease, thalassemias, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other inherited causes of anemia

Question 37

presence of epigastric and LUQ abdominal pain, along with long-term use of NSAID’s, raises a flag for ...?

Answer 37

testing to rule out a bleeding ulcer

Question 38

most common cause of anemia in elderly? micro-/normo-/macrocytic?

Answer 38

anemia of chronic inflammation usually microcytic-normocytic

Question 39

All anemias presenting with hemodynamic instability can improve with...

Answer 39

RBC transfusions