Ob Kaplan Chap 5 Pernatal Lab Testing

Front 1

HIV Screening methods during first trimester

Back 1

Screening
Western blot test

Front 2

how does Western blot test work

Back 2

This definitive test identifies the presence of HIV core and envelope antigens. Triple antiviral therapy is recommended for all HIV-positive women starting at 14 weeks and continuing through delivery. With cesarean delivery and triple antiviral therapy, transmission rates are as low as 1%.

Front 3

How does the ELISA test work

Back 3

This screening test assesses presence of detectable HIV antibodies. A 3-month lag exists between HIV infection and a positive ELISA test. All babies born to HIV-positive women will be HIV antibody positive from passive maternal antibodies

Front 4

" THIRD TRIMESTER LABORATORY TESTS

Back 4

Complete Blood Count (CBC
1-h 50-g oral glucose tolerance test (OGTT)
3-h 100-g OGTT

Front 5

Diabetic Testing

Back 5

1-h 50-g oral glucose tolerance test (OGTT)
3-h 100-g OGTT

Front 6

1-h 50-g oral glucose tolerance test (OGTT)

Back 6

This screening test is administered to all pregnant women between 24 and 28 weeks' gestation. No fasting state is needed. A 50-g glucose load is given, and serum glucose is measured 1 h later. A normal value is <140 mg/dL. Fifteen percent of pregnant women will have an abnormal screening test, which is a value of >140 mg/dL. The next step in management is a 3-h 100-g OGTT.

Front 7

3-h 100-g OGTT

Back 7

This is the definitive test for glucose intolerance in pregnancy. Fifteen percent of women with an
abnormal screening test will be found to have gestational diabetes mellitus. After an overnight
(94, fast, a fasting blood sugar (FBS) is drawn. An FBS >125 mg/dL indicates overt diabetes mellitus,and no further testing is performed. If the FBS is <126 mg/dL, administer a 100-g glucose load,
followed by glucose levels at 1, 2, and 3 h. Normal values are FBS <95 mg/dL, 1 h <180 mg/dL, (2 h <155 mg/dL, and 3 h <140 mg/dL. Gestational diabetes is diagnosed if two or more values are
abnormal. Impaired glucose intolerance is diagnosed if only one value is abnormal.

Front 8

CBC

Back 8

Anemia

Front 9

Normal pregnancy Hb
Nonpregnant female Hb
WHy are they different?

Back 9

1.Normal pregnancy hemoglobin reference range is 10-12 g/dL. 2. nonpregnant female hemoglobin reference range is 12-14 g/dL,
3. normal values in pregnancy will reflect the dilutional effect of greater plasma volume increase than red blood cell (RBC) mass.

Front 10

What are the first trimester test

Back 10

1. Cervical pap smear
2.CBC (Hb/Hct 10-12, MCV<80, Plt ct <150,000, leukocyte 16,000)
3. Hep B
4. HIV
5. Rubella IgG Ab
6. STD
7. HIV
8. Type & screen
9. Urine screen

Front 11

What does complete blood count consist of

Back 11

Hb/Hct
leukocyte ct
MCV
Platelet ct

Front 12

Most reliable indicator of true anemia

Back 12

1. MCV may be the most reliable predictor of true anemia.
2. low hemoglobin and low MCV (<80 ) => most commonly sug-gests iron deficiency or thalassemia.
3. low hemoglobin and high MCV (>100) => suggests folate deficiency.

Front 13

Platelet ct indications in first trimester

Back 13

1. low platelet count (<150,000/mm3) => idiopathic thrombocytopenic purpura or pregnancy-induced thrombocytopenia. DIC is rare.

Front 14

Indications for leukocyte ct in first trimester

Back 14

1. Wbc count in pregnancy is normally up to 16,000/mm3.
2. Leukopenia suggests immune suppression or leukemia.

Front 15

How to determine Rubella immunity

Back 15

presence of rubella antibodies rules out a primary infection during the pregnancy. Antibodies derived from a natural, wild infection lead to lifelong immunity. Antibodies from a live-attenuated virus are not as durable.

Front 16

Who are suspectible to rubella infection?
Tx?

Back 16

An absence of antibodies leaves the woman at risk for a primary rubella infection in pregnancy that can have devastating fetal effects, particularly in the first trimester. Rubella immunization is contraindicated in pregnancy because it is made from a live virus but is recommended after delivery.

Front 17

What are HBV surface Antibodies

Back 17

HBV surface antibodies are expected from a successful vaccination.

Front 18

Components of HBV

Back 18

surface Ab
surface antigen
E antigen

Front 19

What are HBV surface antigen

Back 19

The presence of HBV surface antigen represents either a previous or current infection. HBV surface antigen indicates high risk for vertical transmission of HBV from the mother to the fetus or neonate. This is the only specific hepatitis test obtained routinely on the prenatal laboratory panel.

Front 20

What is HBV E antigen

Back 20

The presence of HBV E antigen signifies a highly infectious state.

Front 21

What does Type, Rh and Ab screen consist of

Back 21

Direct Coombs test
Indirect coombs test or atypical antibody test (ATT)

Front 22

What is the direct coombs test used for

Back 22

The patient's blood type and Rh is determined with the direct Coombs test. If the patient is Rh negative, she is at risk for anti-D isoimmunization.

Front 23

What is the indirect coombs test for

Back 23

1. The presence of atypical RBC antibodies is determined with the indirect Coombs test.
2. Isoimmunization is identified if atypical antibodies are present. 3. Follow-up testing is necessary to identify whether the fetus is at risk.

Front 24

Which cervical culture are done during first trimester

Back 24

Screening cultures for chlamydia and gonorrhea will identify whether the fetus is at risk from delivery through an infected birth canal.

Front 25

STD testing for which organisms

Back 25

1. cervical cultures for chlamydia & gonorrhea
2. Nonspecific screen tests VDRL for syphilis
3. Maternal Hep B surface antigen screen for Hep B

Front 26

Initial Prenatal lab STDs and method used

Back 26

1. Chlamydia/gonorrhea screen=> DNA probes
2. HB virus screen=> HBsAg
3. Syphilis screen=> VDRL/RPR
Definitive=> MHA/FTA
4. HIV screen => ELISA
definitive=> Western blot

Front 27

How is syphilis screened for pregnant women

Back 27

1. Nonspecific screening tests (veneral disease research laboratory [VDRL] or rapid plasma reagin [RPR]) are performed on all pregnant women.
2. Positive screening tests must be followed up with treponema-specific tests (microhemagglutination assay for antibodies to T pallidum [MHA¬TP] or fluorescent treponema antibody absorption [FTA] ).
3. Treatment of syphilis in pregnancy requires penicillin to ensure adequate fetal treatment.

Front 28

Urine screening during first trimester

Back 28

Urinalysis
Culture

Front 29

Purpose of urinalysis during first trimester

Back 29

Assessment of proteinuria, ketones, glucose, leukocytes, and bacteria is important to screen for underlying renal disease, diabetes, and infection.

Front 30

Purpose for urine culture in first trimester

Back 30

Screening for asymptomatic bacteriuria (ASB) is essential. Eight percent of pregnant women have ASB. Left untreated, 30% of ASB progresses to pyelonephritis, which is associated with septic shock, pulmonary edema, and adult respiratory distress syndrome.

Front 31

What is the purpose of PPD or Tine test during first trimester

Back 31

This screening skin test determines previous exposure to TB. A positive test is induration, not erythema. If the screening test is negative, no further follow-up is necessary. TB screening is not done routinely but only on high-risk populations.

Front 32

What is the purpose of chest x-ray during first trimester

Back 32

A chest x-ray is performed to rule out active disease only if the screening skin test is positive.
1. If the chest x-ray is negative, isoniazid (INH) (and vitamin B6) is given for 9 months.
2. If the chest x-ray is positive, induced sputum is cultured and triple medications begun until cultures define the organisms involved. Antituberculosis drugs are not contraindicated in pregnancy.

Front 33

Most common risk factor for HIV in women

Back 33

HIV screening is recommended for all pregnant women, but requires a specific consent. The most common risk factor for HIV in women is heterosexual contact with an IV drug abuser.

Front 34

What is the purpose of ELISA test during first trimester

Back 34

This screening test assesses presence of detectable HIV antibodies. A 3-month lag exists between HIV infection and a positive ELISA test. All babies born to HIV-positive women will be HIV antibody positive from passive maternal antibodies.

Front 35

What is the purpose of Western blot during first trimester

Back 35

This definitive test identifies the presence of HIV core and envelope antigens. Triple antiviral therapy is recommended for all HIV-positive women starting at 14 weeks and continuing through delivery. With cesarean delivery and triple antiviral therapy, transmission rates are as low as 1%.

Front 36

Purpose of cervical pap smear during first trimester

Back 36

Cervical cytologic screening is performed to identify if the mother has cervical dysplasia or malignancy.

Front 37

What is AFP?
When does it peak?
What is it used for ?

Back 37

This is the major serum glycoprotein of the embryo. The concentration peaks at 12 weeks in the fetus and amniotic fluid (AF), then rises until 30 weeks in the maternal serum. Fetal structural defects (open neural tube defect [NTD] and ventral wall defects) result in increased spillage into the amniotic fluid and maternal serum. Other causes include twin pregnancy, placental bleeding, fetal renal disease, and sacrococcygeal teratoma.

Front 38

What are the normal Alpha feto protein changes during pregnancy

Back 38

1. fetal serum- peaks at 12 wks
2. amniotic fluid -peaks at 12 wks
3. maternal serum- peaks at 30 wks