AUBF 10

Amniotic fluid

Volume: approximately 35 mL during the 1st trimester, peaks during the 3rd trimester (approx. 1 L)

Polyhydramnios

results from failure of the fetus to begin swallowing, indicates fetal distress

Oligohydramnios

due to increased fetal swallowing, urinary tract deformities, and membrane leakage

Amniocentesis

transabdominal or transvaginal; performed after the 14th week of gestation

35mL

Volume of amniotic fluid

Fluid for FLM test

transported in ice and refrigerated up to 72 hours prior to testing; filtration or low-speed centrifugation is recommended

Fluid for cytogenic test

incubated at 37C prior to analysis

Fluid for chemical testing

separated from cellular elements and debris ASAP

Fluid for bilirubin analysis

placed in amber bottles

Colorless

Normal (may show slight to moderate turbidity)

Blood-streaked

Traumatic tap, abdominal trauma, intra-amniotic hemorrhage

Yellow

HDN

Dark green

Meconium

Dark red-brown

fetal death

L/S ratio

- thin-layer chromatography

- sphingomyelin used as internal standard; greatly affected by blood and meconium contamination

- ≥2.0

Amniostat-FLM

- agglutination immunoassay

- Uses antisera specific to phosphatidyl glycerol, not

affected by blood and meconium contamination

- positive

Foam stability index

- Modified foam-shake

- 95% ethyl alcohol used as anti-foaming agent

- ≥47

Microviscosity

- Fluorescence-polarization

- albumin used as internal standard >55mg/g

Lamellar bodies

- Resistance pulse counting, Uses the pit channel of hematology analyzers, ≥32 000/ul

- OD at 650 nm, Requires centrifugation at 450x g for 10 min, ≥0.015

Bilirubin

- Spectrophotometry

△A150 plotted on a Liley graph to determine severity of HDN; Hgb

meconium interfere

AFP

- Immunoassay

- Screening test for NTDs

AChE

- Spectrophotometry

- Confirmatory test for NTDs, affected by blood contamination

Random specimen

Routine fecalysis

3 day stool (72 hours)

Quantitative fecal fat analysis

Brown

Normal

Black

Upper gastrointestinal bleeding; iron bismuth, charcoal

Red

Lower gastrointestinal bleeding; beets, rifampin

Pale yellow, white, gray

Bile duct obstruction

Green

Biliverdin, oral antibiotics, green vegetables

Bulky, frothy

Steatorrhea

Ribbon-like, slender

Intestinal constriction

Small, hard

Constipation

Watery

Diarrhea

reducing agents

False negative (gFOBT)

red meat, POD-containing fruits and vegetables, NSAID, aspirin

False positive (gFOBT)

Immunochemical FOBT

anti-human Hgb antibody

Porphyrin-based FOBT

Fluorometric test