Neonatal labs

Question 1

Blood glucose

Answer 1

>35 mg/dL 0-24 hours
>45 mg/dL >24 hours
Many now use 50 mg/dL as cutoff value
hyperglycemia is >150
Treatment for hypoglycemia:
D10W at 2mg/kg slow IV push
Maybe glucagon (converts glycogen to sugar)

Question 2

total white blood cell count

Answer 2

generally, 5,000-30,000
preterm 6,000-19,000
term 10,000-26,000
Limited value in diagnosing infection

Question 3

Granulocytes versus agranulocytes

Answer 3

Granulocytes: neutrophils, basophils, eosinophils
Agranulocytes: lymphocytes, monocytes, macrophages

Question 4

Neutrophils

Answer 4

70% for first few weeks
Often seen during acute bacterial infection (go to inflamed area and phagocytose the organism)
“Left shift” refers to enhanced production of new neutrophils (It takes 13-15d to make a mature neutrophil)

Question 5

I:T ratio

Answer 5

<0.2 is normal. >0.8 carries higher risk of death.
(Immature neutrophils)/(All neutrophils)
=(bands+metamyelocytes+myelocytes)/(segs+bands+metas+myelos)

Question 6

Absolute neutrophil count

Answer 6

>2,000, 0-24 hours
>7,000, after 24 hours
<1,500 is suggestive of infection
Multiply WBCs by all neutrophil percentages
=WBC * (% segs+ % bands+ %metas)

Question 7

Eosinophils

Answer 7

1-3%

Elevated ina allergic response, parasitic infections

Question 8

Basophils

Answer 8

<1%

Seen in allergic response, during healing phase of inflammation

Question 9

Monocytes

Answer 9

4-8%

Elevated in response to viral and chronic bacterial infections (2nd line of defense against bacterial infections)

Question 10

Lymphocytes

Answer 10

30% initially, 60% in first few weeks
Elevated in viral infections
Provide B and T cell immunity

Question 11

Types of antibodies

Answer 11

IgG: crosses placenta, protects babies in 1st months (75%)
IgM: early antibody, produced by fetus in response to intrauterine infection (10%)
IgA: predominately in mucous/saliva, passed in human milk
IgD: Unknown function (<1%)
IgE: unknown function (trace)

Question 12

Platelets

Answer 12

150,000-450,000
>80,000 on days 3-5
Can be nonspecific late sign of infection, may be decreased with fungal infections

Question 13

C-reactive protein

Answer 13

Signals acute inflammation, one of the first serum acute-phase reactants to rise in response to sepsis
Generally returns to normal within 2-7d of successful treatment. Persistent rise indicates persistent infection/meningitis

Question 14

Gram positive cocci

Answer 14

In pairs: strep or staph
In chains: strep
In clusters: staph

Question 15

Gram negative bugs

Answer 15

rods: e.coli
diploid: neisseria

Question 16

Indirect coombs test

Answer 16

Used to screen pregnant women for antibodies that may cause hemolytic disease of newborn (as in ABO or Rh incompatibility)

Question 17

Direct coombs test

Answer 17

looks for autoimmune hemolytic anemia

Question 18

categories of hypoxia

Answer 18

Hypoxemic hypoxia
anemic hypoxia
circulatory hypoxia
histologic hypoxia

Question 19

PaO2

Answer 19

50-80 (term)

45-65 (preterm)

Question 20

base deficit/excess

Answer 20

-2 to +2
base excess indicates too much buffer (metabolic alkalosis)
base deficit indicates too little buffer (metabolic acidosis)

Question 21

causes of metabolic acidosis

Answer 21

Diarrhea
 Small bowel drainage
 Hyperalimentation
 Ingestion of Chloridecontaining compounds
 Renal Tubular Acidosis
 Renal Failure
 Carbonic Anhydrase 
Deficiency
 Lactic Acidosis
 Tissue Hypoxia
 Sepsis
 Neonatal Cold Stress
 Ketoacidosis
 Diabetes Mellitus
 Starvation
 Ingestion of Toxins
 Inborn Errors of Metabolism

Question 22

causes of metabolic alkalosis

Answer 22

Vomiting
 Nasogastric Suctioning
 Congenital Chloride-Wasting 
Diarrhea
 Dehydration
 Diuretic Therapy
 Steroid Therapy
 Cushing’s Syndrome
 Bartter’s Syndrome
 Sodium Bicarbonate Use
 Hypokalemia
 Hypochloremia
 Chewing Tobacco
 Massive Blood Transfusion
 Cystic Fibrosis Infants Fed 
Regular Formula or BM

Question 23

causes of respiratory acidosis

Answer 23

Lung Disease
 Upper Airway Obstruction
 Small Airway Obstruction
 Chronic Obstructive Disease
 Pneumonia
 Pulmonary Edema
 RDS, ARDS
 Aspiration
 Pulmonary Hypoplasia
 Impaired Lung Motion
 Pleural Effusion
 Pneumothorax
 Thoracic Cage Abnormalities
 Apnea
 Neurologic or Neuromuscular 
Disorders Affecting 
Respiration

Question 24

causes of respiratory alkalosis

Answer 24

 Anxiety
 Fever
 Sepsis
 Hypoxemia
 Pneumonia
 Atelectasis
 Pulmonary Emboli
 Congestive Heart Failure
 Asthma
 Central Nervous Syndrome 
Disorders
 Liver Failure
 Reye’s Syndrome
 Hyperthyroidism
 Salicylate Poisoning
 Mechanical Ventilation

Question 25

bilirubin

Answer 25

produced from catabolism of hem-containing proteins
Unconjugated (indirect): lipid soluble, bound to albumin.
Conjugated (direct): water soluble and able to be eliminated.
Unconjugated is converted to conjugated by liver or by phototherapy. Albumin is needed to transport bilirubin to the liver.

Question 26

sodium

Answer 26

135-145

helps conduct neuromuscular impulses, maintain intravasular osmolarity, and acid-base balance

Question 27

Potassium

Answer 27

3.5-5.5
responsible for cardiac and skeletal muscle contraction
abnormal can cause weakness an arrhythmias

Question 28

chloride

Answer 28

96-111
Works with Na+
to maintain acid/base balance, transmit nerve impulses, and
regulate fluid in and out of cells

Question 29

Calcium

Answer 29

Term: iCa >1.1, serum Ca 8.0-10.8
Preterm: iCa>1, serum Ca 7-10.8
Needed for bone mineralization.
Because dietary intake is decreased in the first few days, serum concentration
decreases in the first day of life. ~30% will develop hypocalcemi in first 2 days, usually improves in 1-3 days with feedings, renal phosphorus excretion, and improved parathyroid function

Question 30

Phosphorus

Answer 30

5-7.8
Needed for bone mineralization, erythrocyte function, cell metabolism and the
generation and storage of energy

Question 31

Magnesium

Answer 31

1.6-2.8
Needed for energy production, cell membrane function, and protein synthesis.
HpoMg is often seen with hypoCa; need to correct hypoMg to correct hypoCa