Labs (Quiz 2) Flashcards
Examples of universal and selected screenings a different ages throughout childhood
Newborn:
- ID genetic, metabolic, developmental issues via blood on filter paper (HRSA recommends 30 dos, all states do at least 21, some >30)
- newest NBS is for critical congenital heart disease (pulse oximetry and pulse)
- Hearing screening in 43 states + PR and DC
IDA: 12 mo Hgb screening
Rationale for newborn screening
Testing, Tracking, Treating
Role of APRN in newborn screening
- Educate parents during pregnancy
- f/u abnl results asap - locate baby
- if +, arrange f/u w/appropriate specialists (use ACT sheets)
- Continue f/u and support in PC
- complete medical hx
- Signs illness (GI, cardiac, neuro)
- Dvptl/neuro f/u
- Continue care w/specialists
- Reassure; stress importance of adherence
Available tools for newborn screening
- National Newborn Screening and Genetics Resource Center: comprehensive source of info
- American College of Medical Genetics
- Includes “ACT” sheets (ACTion) - info for providers what to do if screen +, specialists
- immediate steps for + newborn screening: family contact, specialist, evaluation, confirmatory testing, tx, education, algorithm including BW results
- Includes “ACT” sheets (ACTion) - info for providers what to do if screen +, specialists
- March of Dimes: consumer friendly reading, video about screening
Types of hyperbilirubinemia
Bilirubin is product of RBC breakdown.
- unconjugated (indirect) bilirubin: 2/2 abnormality of bilirubin metabolism / excretion (physiologic jaundice of newborn) (our focus)
- conjugated (direct) bilirubin: sugars are attached to bilirubin, 2/2 biliary obstruction/cholestasis (hepatitis, pancreatitis, biliary atresia, sepsis)
What are breast milk jaundice and breastfeeding failure jaundice?
How are they managed?
-
Breast milk jaundice:
- = physiologic jaundice > 1 week of age
- Presents 3-5 days of life, peaks 2 weeks of age, declines 3-12 weeks
- Usually total bili >5mg/dL, but generally mild and does not require intervention >> monitor for increases
-
Breastfeeding failure jaundice
- sub-optimal breastfeeding >> inadequate intake >> decreased stools
- First 7 days of life
- Results in excessive weight and fluid loss and decreased bili elimination
- Prevention: breastfeed 8-12x/day
**if babies have jaundice that require intervention – phototherapy, bili blanket, blood exchange transfusion
Causes of unconjugated hyperbilirubinemia
- Hemolysis: blood group incompatabilit, infection, hemoglobinopathies, RBC enzyme defects, RBC membrane DOs…
- No hemolysis: breast milk jaundice, infant of mother w/DM, internal hemorrhage, physiologic jaundice, polycythemia, hypothyroidism, Gilbert syndrome, pyloric stenosis…
Clinical sx of hyperbilirubinemia
-
Simple jaundice: bili >5-6 mg/dL, skin yellow (60% of newborns in 1st wk, cranial-caudal progression, best seen in periphery of conjunctivae and in oral mm (under tongue, hard palate))
- may have some sleepiness, feeding difficulty
-
Acute bilirubin encephalopathy: as above+ lethargy, hypotonia, poor suck
- may have irritability, hypertonia, high pitched cry, fever, seizures
-
Kernicterus: above + athetoid cerebral palsy, hearing loss, gase palsies, dental enamel hypoplasia
- ●TB >20 and ≤25 mg/dL – Risk of kernicterus usually only in conjunction with a co-morbid condition
- ●TB >25 and ≤30 mg/dL – 6 percent
- ●TB >30 and ≤35 mg/dL – 14 to 25 percent
- ●TB >35 mg/dL – Almost all infants will have signs of kernicterus
Bilirubin: nl range, when increased risk for kernicterus, nl peak
- Bilirubin
- Elevated > 2.5-3mg/dL
- Increased risk for kernicterus > 20mg/dL
- Bilirubin peaks at age 3-5days (5-7days if premature; also later in Asian infants)
- Mean peak total serum bilirubin is 6mg/dL (higher in Asian infants)
Transcutaneous vs serum bili
-
Transcutaneous:
- Advantages: used as screening tool in newborns; no blood lab needed
- Disadvantages: TcB does not distinguish between conjugated + unconjugated; levels may be affected by skin pigmentation
- Follow up with serum TB if TcB >95th percentile OR TcB > 13mg/dL
-
Serum:
- Total and direct bilirubin levels
- Used to confirm TcB values if questioning validity of TcB
- Used if infant undergoing phototherapy
- Consider cholestasis if conjugate bilirubin >1mg/dL + TB <5mg/dL
* Interpret all levels according to baby’s age in hours
Other labs that may be useful in assessing hyperbilirubinemia
- CBC (for H/H)
- Low hemoglobin may indicate hemolysis
- Peripheral blood smear (for RBC morphology)
- Hemolysis can be confirmed by presence of fragmented cells in smear
- Reticulocyte count
- Rising reticulocyte count is consistent with RBC destruction
- Coomb’s test
- Comparison of mother and infant’s blood type to see if there’s a possibility of isoimmune hemolytic disease (mother’s antibodies destroy newborn’s RBC)
- G6PD measurement
- If either parent is Mediterranean, Nigerian or East Asian OR
- If TB > 18/mg/dL
Risk factors for hyperbilirubinemia
major, minor, reduced
What tool is available to determine phototherapy needs, how is it used?
When to send to the hospital for hyperbilirubinemia?
Components of a CBC
RBC indices
(not #s)
Macro / micro / normo cytic anemias
-
Microcytic anemia: MCV low
- e.g. IDA - universal screening at 12mo but still high prevalence, 9% ado females have IDA (no universal screening). Risks: premature, BF w/o iron supp after 6mo, hispanic, lead exposure, heavy menses, cow’s milk before 12mo
- Macrocytic anemia: MCV high
- Normocytic anemia: MCV nl