Lab Values

Question 1

When can hCG be detected in blood/urine?

Answer 1

7-9 days after fertilization (Williams)

8-10 days (Gabbe)

Question 2

When does hCG peak?

Answer 2

9-10wks

Question 3

When does hCG decline to its nadir?

Answer 3

16wks (Williams)

20wks (Gabbe)

Question 4

What hCG patterns are indicative of ectopic or SAB?

Answer 4

hCG<1500

falls or plateaus; fails to reach 50% increase in 48h

Question 5

Explain indirect Coombs testing

Answer 5

• mix maternal serum w/ standard reagent that carries antigens
• will react w/ clinically significant Abs
• unbound Abs identified (e.g. Rh D)

Question 6

Which type of antibodies are most concerning?

Answer 6

IgG

IgM does not cross placenta

Question 7

normal WBCs

Answer 7

1st: 3.9-13.8
2nd: 4.5-14.8
3rd: 5.3-16.9
term: 4.2-22.2

Question 8

normal platelets

Answer 8

1st: 149-433k
2nd: 135-391k
3rd: 121-429k
term: 121-397k

Question 9

normal Hgb

Answer 9

1st: 11.0-14.3
2nd: 10.5-13.7
3rd: 11.0-13.8
term: 11.0-14.6

Question 10

normal Hct

Answer 10

1st: 33-41%
2nd: 32-38%
3rd: 33-40%
term: 33-42%

Question 11

normal ferritin

Answer 11

1st: 10-123
2nd: 10-101
3rd: 10-48
term: 10-64

Question 12

normal iron

Answer 12

1st: 40-215
2nd: 40-220
3rd: 40-193
term: 40-193

Question 13

What spot protein:creatinine ratio value is significant and what are next steps?

Answer 13

0.15-0.29

consider 24h urine

Question 14

normal urine protein

Answer 14

1st: 19-141
2nd: 47-186
3rd: 46-185

Question 15

normal Na

Answer 15

1st: 131-139
2nd: 129-142
3rd: 127-143
term: 124-141

Question 16

What is hep B detected?

Answer 16

hep B surface antigen (HBsAg) = first serological marker

Question 17

What is indicative of hep B resolution?

Answer 17

Abs to HBsAg (anti-Hbs)

Question 18

Explain seronegative vs seropositive for varicella

Answer 18

seropositive = immune

seronegative = non-immune –> vaccinate PP

Question 19

What BPs are indicative of HTN?

Answer 19

140-160s sys OR 90-110 dia

AND

at least 2 elevated BPs at least 4h but no more than 7 days apart

Question 20

What BPs are indicative of severe HTN?

Answer 20

> /= 160 / >/= 110

Question 21

What is indicative of preeclampsia?

Answer 21

severe gHTN + proteinuria

Question 22

What platelet values are indicative of thrombocytopenia?

Answer 22

<100,000 –> evaluate for preeclampsia

Question 23

What serum creatinine values are significant?

Answer 23

> 1.1 = renal insufficiency

Question 24

What defines proteinuria?

Answer 24

• 1+ or more by dipstick testing on 2 occasions OR
• protein:creatinine ratio >0.30 OR
• > /=300mg in 24h urine collection

Question 25

How is GDM dx’ed?

Answer 25

1h: 130-140 –>
3h:
- fasting: 95-105
- 1h: 180-190
- 2h: 155-165
- 3h: 140-145

Question 26

Which pts are at high risk of thyroid disease?

Answer 26

serum TSH at first visit for:

1) hx thyroid dysfunction or prior thyroid surgery
2) >30yo
3) sx of thyroid dysfunction or presence of goiter
4) thyroid peroxidase antibody positive
5) type 1 DM
6) hx head/neck radiation
7) family hx thyroid dysfunction
8) morbid obesity (BMI >40)
9) use of amiodarone or lithium
10) unexplained infertility
11) living in area of iodine insufficiency

Question 27

What values of are indicative of primary hypothyroidism?

Answer 27

1st: TSH > 2.5

2nd, 3rd: TSH > 3.0