AMNIOTIC FLUID Flashcards by Mr. Wendell

T or F
Doctors are the only one allowed to collect Amniotic Fluid

T
(specifically OBGYNE)

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Amniotic Fluid is found around the developing fetus inside a membranous sac called?

amnion

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Main Function of AF

– Serves to cushion and protect the developing fetus
– Also serves a key role in the exchange of water and molecules between the fetus and the maternal circulation
…….Source of water for the baby

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The laboratory performs several crucial tests on amniotic fluid to?

assess the status of the fetus.

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(4) The laboratory performs several crucial tests on AF

Test to diagnose genetic and congenital disorders before birth
Test to detect fetal distress from hemolytic disease of the newborn (HDN) or from infection
Test to assess fetal lung maturity
Assessment of the ability of the fetus to survive early delivery

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Amniotic fluid is formed from the?

placenta

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Volume of amniotic fluid increases steadily throughout the pregnancy up to a maximum of?

1100-1500 mL

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The maximum volume throughout the pregnancy occurs at what week at gestation?

36 weeks of gestation

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As the baby matures

more amniotic fluid is produced by the mother

(so Volume and maturity = directly proportional)

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When fetal urine production begins, the chemical composition of the amniotic fluid changes.

This leads to increased production of?

creatinine

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At commencement of fetal urine production, fetal swallowing of amniotic fluid begins and this regulates the?

formation of fetal urine

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source of nutrients for the baby (especially water)

Amniotic fluid

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How the baby takes up nutrients and water inside the womb

Intramembranous fluid transfer

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amniotic fluid suffix

amnios

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Decreased fetal swallowing resulting in increased amniotic fluid volume

> 2000 mL or >2L

POLYHYDRAMNIOS

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Decreased amounts of amniotic fluid

Can occur with premature rupture of the membranes and Congenital malformations

<1000 mL or <1L

OLIGOHYDRAMNIOS

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termed as the Collection of amniotic fluid

AMNIOCENTESIS

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Injection of syringe into the abdominal walls of patient

Transabdominal

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Through the vagina

Transvaginal

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Needle aspiration is introduced into the amniotic sac, usually? (what type of spec. collection method)

transabdominally

(with simultaneous use of ultrasound)

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The addition of __________ has helped to make the procedure safer especially if performed between __ and __ weeks of gestation for genetic studies.

ultrasound

15 and 18 weeks

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Amount collected of AF is usually

10-20 mL (max of 30)

(with collection into several different syringes to prevent the contamination of all specimens with the blood from initial puncture)

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What container is used for the AF specimen?

sterile plastic specimen containers

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_______ containers are less desirable as cells have more tendency to adhere to the glass surface

and Consistency and morphology of cellular elements are affected

Glass containers

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Normal Amniotic Fluid color/appearance

COLORLESS to PALE YELLOW Slightly turbid due to Fetal cells (Vernix and Hair)

protective coating that forms on baby's skin in utero(wapa naanak)

Vernix

a natural moisturizer and has antibacterial properties

Vernix

(3) Storage of AF

A. Specimen for Cell Culture and Chromosomal Studies B. Specimen for phospholipid analysis C. Specimen for chemical analysis

Identify what STORAGE type is mentioned Stored at Room temperature to keep the fetal cells alive

Specimen for Cell Culture and Chromosomal Studies

Identify what STORAGE type is mentioned Transported on ice and centrifuged at 500g and the supernatant saved for testing. If blood is present, specimen should be centrifuged to prevent hemolysis from altering the test results

Specimen for phospholipid analysis

Anything involved with lipid and chemical procedures, all specimens should be?

preserved/refrigerated

Identify what STORAGE type is mentioned - Stored at any length of time but must be centrifuged.

Specimen for chemical analysis

If samples for chemical analysis need to be stored more than 24 hours, they must be?

frozen

Microscopic test to differentiate amniotic fluid from maternal urine.

Fern Test

(2) Fern Test Can be used to test if the patient is:

1. Pregnant 2. There is premature rupture of the amniotic fluid

Fern test is done in a way where

Vaginal fluid is spread out on a glass slide and allowed to dry at room temperature.

The slide of Fern test is observed for

The slide is observed for fern-like crystals that are a positive screen test for amniotic fluid.

positive fern test

Presence of fern-like crystals due to the; Crystallization of cervical mucus due to increased concentration of protein and electrolytes during pregnancy

GROSS EXAM State the significance colorless AF

Normal - may show slight to moderate turbidity

GROSS EXAM State the significance a Blood Streaked AF

Traumatic Tap Abdominal Trauma Intra Amniotic Hemorrhage

GROSS EXAM State the significance a Yellow AF

Hemolytic Disease of the newborn

GROSS EXAM State the significance a Dark green AF

Meconium

GROSS EXAM State the significance a Dark red brown AF

Fetal Death

1st Phase of Amniotic fluid

Development of amniotic fluid = water and electrolytes

2nd Phase of Amniotic fluid

- Usually happens on the 12th – 14th week (3rd month) - Contains protein, carbohydrates, phospholipids, urea, creatinine *Facilitate fetal growth

When does the 2nd Phase of Amniotic fluid happen?

12th – 14th week (3rd month)

What does the 2nd Phase of Amniotic fluid composed of?

protein, carbohydrates, phospholipids, urea, creatinine *Facilitate fetal growth

To know if the baby is okay (no genetic disorders nor birth defects)

Test for Fetal Lung Maturity

TEST FOR FETAL LUNG MATURITY are lung surfactants

Lecithin and Sphingomyelin (L/S Ratio)

TEST FOR FETAL LUNG MATURITY o Lower surface tension within alveoli (prevents alveolar collapse) o Prevent invasion of certain pathogens o Mediate immune responses

L/S Ratio

As the baby matures, L/S ratio?

increases 2:1 [normal ratio (L:S)] *If normal = fetus can be safely delivered with well-functioning lungs

PRINCIPLE of L/S Ratio

Thin Layer Chromatography

DETAILS of L/S Ratio

Sphingomyelin is used as internal standard, greatly affected by blood and meconium contamination

is used as internal standard, greatly affected by blood and meconium contamination

Sphingomyelin

NORMAL VALUES of L/S Ratio

>2.0

TEST FOR FETAL LUNG MATURITY PRINCIPLE of Amniostat FLM

Agglutination immunoassay

DETAILS of Amniostat FLM

Uses antisera specific to PHOSPHATIDYLGLYCEROL o Main substance to detect o Marker for pulmonary maturity - Not affected by blood and meconium contamination

NORMAL VALUES of Amniostat FLM

Positive

TEST FOR FETAL LUNG MATURITY PRINCIPLE of Foam Stability Index

Modified Foam shake

DETAILS of Foam Stability Index

95% ethanol used as anti-foaming agent

NORMAL VALUES of Foam Stability Index

>47

TEST FOR FETAL LUNG MATURITY PRINCIPLE of Microviscosity

Fluorescence polarization

DETAILS of Microviscosity

Albumin used as internal standard

NORMAL VALUES of Microviscosity

>55 mg/g

TEST FOR FETAL LUNG MATURITY PRINCIPLE of Lamellar Body Count

Resistance pulse counting

DETAILS of Lamellar Body Count

Uses the platelet channel of hematology analyzers

NORMAL VALUES of Lamellar Body Count

>32,000/mL

PRINCIPLE of OD at 650nm

Spectrophotometry

DETAILS of OD at 650nm

Requires centrifugation at 2000 g for 10 minutes

NORMAL VALUES of OD at 650nm

>0.150

If unit si *nm* (or numbers), principle is always

spectrophotometry

Identify what test is this If positive, the baby does not receive enough oxygen

Test for Fetal Distress

Test for Fetal Distress (2) How to know when the test is needed?

- There are changes in baby’s heartrate during ultrasound - Slow to no movement inside the womb

TEST FOR FETAL DISTRESS PRINCIPLE of Bilirubin

Spectrophotometry

DETAILS of Bilirubin

- Wavelength plotted on a LILEY GRAPH to determine the severity of HDN. - Presence of Hgb and meconium can interfere with the results *Increased hgb = increased bilirubin

NORMAL VALUES of Bilirubin

<0.025

TEST FOR FETAL DISTRESS PRINCIPLE of Alpha Fetoprotein (AFP)

Immunoassay

DETAILS of Alpha Fetoprotein (AFP)

Screening test for Neural Tube Defects

NORMAL VALUES of Alpha Fetoprotein (AFP)

<2.0 MoM

TEST FOR FETAL DISTRESS PRINCIPLE of Acetylcholinesterase (AChE)

Spectrophotometry

DETAILS of Acetylcholinesterase (AChE)

Confirmatory test for NTD and greatly affected by blood contamination

NORMAL VALUESof Acetylcholinesterase (AChE)

Undetectable