This document discusses common laboratory procedures used to evaluate alterations in the endocrine system. It describes assays that measure hormone levels in the blood, including stimulation and suppression tests. It provides examples of how thyroid hormone levels can indicate hypo- or hyperthyroidism. Tests are also described for radioactive iodine uptake, thyroid scans, basal metabolic rate, fasting blood glucose, oral glucose tolerance, and glycosylated hemoglobin A1C. The purpose, procedure, and interpretation of results are covered for each test.

1. LABORATORY PROCEDURES:
ALTERATION IN ENDOCRINE
SYSTEM
By: ROMMEL LUIS C. ISRAEL III
BY: ROMMEL LUIS C. ISRAEL III 1

2. COMMON LABORATORY
PROCEDURES
Hormone Levels Assay
These are blood examinations
for the levels of individual
hormones
BY: ROMMEL LUIS C. ISRAEL III 2

3. COMMON LABORATORY
PROCEDURES
Hormone Levels Assay
Measurements can also be done
after stimulation and suppression
of the secretions- Stimulation and
Suppression tests
BY: ROMMEL LUIS C. ISRAEL III 3

4. COMMON LABORATORY
PROCEDURES
Hormone Levels ofT3/T4
Usually done to diagnose
hypo/hyperthyroidism
BY: ROMMEL LUIS C. ISRAEL III 4

5. COMMON LABORATORY
PROCEDURES
Hormone Levels ofT3/T4
IfT3 is elevated,T4 is
elevated andTSH is
depressed Primary
HYPERthyroidism
BY: ROMMEL LUIS C. ISRAEL III 5

6. COMMON LABORATORY
PROCEDURES
Hormone Levels ofT3/T4
IfT3 is depressed,T4 is
depressed andTSH is
elevated Primary
HYPOthyoidism
BY: ROMMEL LUIS C. ISRAEL III 6

7. COMMON LABORATORY
PROCEDURES
Radio-Active iodine uptake (RAI)
This is a thyroid function test to
measure the absorption of the
injected iodine isotope by the
thyroid tissue
BY: ROMMEL LUIS C. ISRAEL III 7

8. COMMON LABORATORY
PROCEDURES
Radio-Active iodine uptake (RAI)
Increased uptake may indicate
HYPERfunctioning gland
Decreased uptake my indicate
HYPOfunctioning gland
BY: ROMMEL LUIS C. ISRAEL III 8

9. COMMON LABORATORY
PROCEDURES
Thyroid Scan
Performed to identify nodules
or growth in the thyroid gland
RAI is used
BY: ROMMEL LUIS C. ISRAEL III 9

10. COMMON LABORATORY
PROCEDURES
Thyroid Scan
Pretest- Check for pregnancy,
Thyroid medication may be
withheld temporarily, advise NPO
Post-test- Ensure proper disposal
of body wastes
BY: ROMMEL LUIS C. ISRAEL III 10

11. COMMON LABORATORY
PROCEDURES
BY: ROMMEL LUIS C. ISRAEL III 11
The BMR has a long history in the evaluation
of thyroid function.
It measures the oxygen consumption under
basal conditions of overnight fast and rest
from mental and physical exertion.
it can be estimated from the oxygen
consumed over a timed interval by analysis of
samples of expired air

12. COMMON LABORATORY
PROCEDURES
BY: ROMMEL LUIS C. ISRAEL III 12
BMR
The test indirectly measures metabolic energy
expenditure or heat production.
Results are expressed as the percentage of
deviation from normal after appropriate
corrections have been made for age, sex, and
body surface area.
Low values are suggestive of
hypothyroidism, and high values reflect
thyrotoxicosis.

13. COMMON LABORATORY
PROCEDURES
FASTING BLOOD GLUCOSE
Aids in the diagnosis of Diabetes
Pre-test: NPO for 8 hours
Normal FBS- 80-109 mg/dL
DM- 126 mg/dL and above
BY: ROMMEL LUIS C. ISRAEL III 13

14. COMMON LABORATORY
PROCEDURES
GLUCOSE tolerance test
Aids in the diagnosis of DM
Pre-test: Provide high-
carbohydrate foods x 3 days,
instruct to avoid caffeine, alcohol
and smoking, NPO 10 hours prior
to test
BY: ROMMEL LUIS C. ISRAEL III 14

15. COMMON LABORATORY
PROCEDURES
GLUCOSE tolerance test
Post-test: avoid strenuous
activity for 8 hours
Normal OGTT- 1 and 2 hours
post-prandial- glucose is less than
200 mg/dL
BY: ROMMEL LUIS C. ISRAEL III 15

16. COMMON LABORATORY
PROCEDURES
Glycosylated Hemoglobin A 1-C
Blood glucose bound to RBC
hemoglobin
Reflects how well blood glucose is
controlled for the past 3 months
FASTING is NOT required!
BY: ROMMEL LUIS C. ISRAEL III 16

17. COMMON LABORATORY
PROCEDURES
Glycosylated Hemoglobin A 1-C
Normal level- expressed as percentage
of total hemoglobin
N- 4-7%
Good control- 7.5%or less
Fair control- 7.5 % to 8.9%
Poor control- 9% and above
BY: ROMMEL LUIS C. ISRAEL III 17