1. Laboratory test The Thyroid gland
ANIK WIDIJANTI
Clinical Pathology Department Saiful Anwar Hospital / Medical Faculty Brawijaya University MALANG

2. ROUTINE LABORATORY EVALUATION
TSH : Thyroid stimulating hormone
Thyroxine (T4) and Triiodothyronine (T3) (free / total)
ETIOLOGY TEST OF THYROID DYSFUNCTION
Autoimmune thyroid disease is detected by circulating antibodies against TPO and Tg. As antibodies to Tg alone is uncommon, it is reasonable to measure only TPO antibodies

3. Characteristics of Circulating T4 and T 3
Hormone property T4
T 3
Total serum concentrations
8µg/dl
0.14 µg/dl
Fraction of total hormone in free form (serum)
0.02 %
0.3 %
Free (unbound hormone) in serum
21 X M
6 X M
Serum half life
7 d
0.75 d
Fraction directly from the thyroid
100 %
20 %
Production rate, including peripheral conversion
90 µg/d
32 µg/d
Intracellular hormone fraction
~ 20 %
~ 70 %
Relative metabolic potency
0.3 1
Receptor binding
10-10 M
10-11 M

4. Measure TSH Elevated Normal Measure unbound T4
Pituitary disease suspected
Normal
Low No
yes
Primary
hypothyroidism
No further
test
Measure
unbound T4
Mild
hypothyroidism
TPO Ab (+)
TPO Ab (-)
Low
Normal
TPO Ab (+)
or symptomatic
TPO Ab (-)
or no
symptoms
No further test
Rule out other Causes of
hypothyroidism
Autoimmun
hypothyroidism
Rule out drug effects, sick Euthyroid syndrome, then
Evaluate anterior pituitary function
T4 treatment
Annual follow up
T4 treatment

5. Aplication of TSH Examination
BIOASSAY
VARIATION OF SENSITIVITY :
INCONVINIENT
RIAs
SENSITIVITY 1mU/L
CROSS REACTION < 1 %
HYPOTHYROID
IRMAs
SENSITIVITY
X RIAs
HYPO + EUTTHROID
HYPERTIHYROID
TSH mU/L
EUTHYROID
HYPOTHYROID
4 m U/L I II
Detection
ICMAs
< 0.1
IMMUNO ASSAY
I : 5 – 7 m U/L
IMMUNO ASSAY
III : – 0.02
II : O.1 – 0.2
IV : – 0.002

6. THYROID AUTOIMUN (AIT)
Anti Tg
Sitoplasma folikular
Complement activation (-)
Anti TPO
105 kd, mikrosomal
Thyroid peroksidase enzyme
Korelasi (+) anti TPO & PPTD
Complement activation (+)
AntiTSH-R
 hypertiroid
 hypotiroid
!! in GD
Ab bispesifik :Ab TPO more frequent & higher than anti Tg,
Only Anti TPO (+) : rare
Anti TPO & anti Tg pd GD : not establish (discussion)
Routin Deteksion Ab tiroid : only anti TPO

7. Prevalensi anti TPO Ab bispesifik Anti TPO & AIT
PPTD (post partum thyroiditis) : 16 %
Grave disease : 34,6 %
Hasimoto thyroiditis : 40.5 %
Ab bispesifik
PPTD : 16 %
N population : 1,4 %
Anti TPO & AIT
Clinical relevancy : not clearly
Correlation with active clinical disease
Strong correlation with risk of PPTD

8. Anti TPO for predict PPTD
Variation of sensitivity & spesificity
Depend on when anti TPO examined
PPTD (-) when anti TPO (-) 
Screening anti TPO in early pregnancy

9. Anti Tg Tiroglobulin (Tg) Jodium Defisiensi IHA > 1 : 1000
Prekursor thyroid H
Produced in thyroid gland
Secretion to colloid
Thyroid H reserved
Reseptor apical Tg for
traffic Tg intraselular
Early indikator PPTD
Rise in GD
Target anti Tg
Anti Tg
Jodium Defisiensi
Detection AIT (Goiter +)
Monitoring jodium Tx
IHA > 1 : 1000
T Hasimoto : 80 %
GD : 60 %
Tiroid carcinoma: 30 %
IHA < 1 : 1000
Normal : 3-18 %
Anemia Pernisiosa
Syogren Syndrome

10. SERUM Tg EXAMINATION Not distinguish : PPTD & GD
Interferens : serum anti Tg (reaction of anti Tg + anti Tg antibodi in immunoassay kit),  examination simultaneously Tg + anti Tg

11. Thank you for
your attention