An update in ada as a diagnostic tool.pptx new

An Update in ADA as AAn Update in ADA as A
Diagnostic ToolDiagnostic Tool
DR.AMINA NUR
RESIDENT,PHASE-A
INTERNAL MEDICINE
BSMMU

What is ADAWhat is ADA
Adenosine deaminase (also known as
Adenosine aminhydrolase, or ADA) is
an enzyme involved in purine
metabolism.
Needed for the breakdown
of adenosine from food and for the
turnover of nucleic acids in tissues.
Present in virtually all mammalian cells,
its primary function in humans is the
development and maintenance of the
immune system.[

StructureStructure
 ADA exists in both small form (as a monomer) and large form
(as a dimer-complex). In the monomer form, the enzyme is a
polypeptide chain, folded into eight strands of parallel α/β
barrels, which surround a central deep pocket that is the
active site.
 In addition to the eight central β-barrels and eight peripheral
α-helices, ADA also contains five additional helices: residues
19-76 fold into three helices, located between β1 and α1
folds; and two antiparallel carboxy-terminal helices are
located across the amino-terminal of the β-barrel.

StructureStructure
 There are 2 isoforms of ADA: ADA1 and ADA2.
 ADA1 is found in most body cells,
particularly lymphocytes and macrophages.ADA2
was first found in human spleen and in tissues
including the macrophage.
 ADA2 is found predominantly in the human
plasma and serum, and exists solely as a
homodimer. In tubercular effusion we detect
ADA2.

Biological FunctionBiological Function
 ADA is considered one of the key enzymes of
purine metabolism. Primarily, ADA in human
is involved in the development and
maintenance of the immune system.
 However, ADA association has also been
observed with epithelial cell differentiation,
neurotransmission, and gestation
maintenance.

Clinical significanceClinical significance
 Adenosine deaminase (ADA) is an endogenous tissue
enzyme which is released into the serum in patients with
different types of malignancies and infections, including
viral hepatitis, infectious mononucleosis, typhoid fever,
and tuberculosis.
 In pleural fluid, elevated ADA levels are very commonly
associated with tuberculosis.
 In CSF, ADA is elevated in cases of tuberculous
meningitis.

Clinical significanceClinical significance
Adenosine deaminase (ADA) deficiency
typically causes severe combined
immunodeficiency (SCID) in infants who
present with growth failure, opportunistic
infections, lymphopenia, and defective
cellular and humoral immune function.

Value of Adenosine Deaminase (ADA) Activity inValue of Adenosine Deaminase (ADA) Activity in
Tubercular SerositisTubercular Serositis
 Tuberculosis is one of the oldest and
commonest infectious diseases which usually
affects lung but extra pulmonary tuberculosis
is also common, of which serosal tuberculosis
is one.
 The diagnosis of extra pulmonary
tuberculosis requires investigation of pleural
fluid biochemistry, cytology and pleural
biopsy.

Value of Adenosine Deaminase (ADA) Activity inValue of Adenosine Deaminase (ADA) Activity in
Tubercular SerositisTubercular Serositis
 Positivity for AFB and Histopathological study of pleura is
very low and culture is very time consuming. ELISA, PCR &
Interferon are very expensive tests.
 Adenosine deaminase has been proposed to be a useful
surrogate marker for tuberculosis in pleural, pericardial and
peritoneal fluids.
 The ADA assay principle is based on the detection of either
hydrogen peroxide or ammonia after enzymatic deamination
of adenosine to inosine by ADA.

VALUE OF ADENOSINE DEAMINASE (ADA)VALUE OF ADENOSINE DEAMINASE (ADA)
ACTIVITY IN TUBERCULAR SEROSITISACTIVITY IN TUBERCULAR SEROSITIS
 The increase in the ADA activity in
patients with TB may indicate the cellular
immune response and T lymphocyte
activation in the disease.
 T lymphocytes have ADA level 10 to 12
times higher than B lymphocytes. ADA activity
varies depending on the proliferative status and
maturity of cells.

Adenosine Deaminase (ADA) Level inAdenosine Deaminase (ADA) Level in
Tubercular Pleural EffusionTubercular Pleural Effusion
 Pleural effusion is a common chest problem,
yet it is difficult to establish the aetiological
diagnosis in as many as 20% cases in spite
of good history, thorough clinical, radiological,
full examination of aspirated fluid and pleural
biopsy1
. So as a simple, rapid and reliable
diagnostic test we need ADA to establish the
aetiology of pleural effusion.

Adenosine Deaminase (ADA) Level in TubercularAdenosine Deaminase (ADA) Level in Tubercular
Pleural EffusionPleural Effusion
 In a journal of Lung India, an official
publication of Indian chest society ,it has
been concluded that If 36 IU/L is taken as
cut of limit the sensitivity and specificity of
ADA for tuberculosis is 100 % and 77.7 %.
 More than 100 IU/L was exclusively seen in
tubercular pleural effusion.

 According to Southeast Asian J Trop Med Public
Health Study, the lowest cutoff value for enzyme
activity in pleural fluid of patients with TB was 45
IU/l and the sensitivity and specificity for diagnosis
were 76.10% and 100%, respectively.
 Therefore, the measurement of ADA in tubercular
pleural effusion has a utility in the diagnosis of
tuberculosis when other clinical and laboratory tests
are negative.

 In European Respiratory Journal, it has
been stated that in tuberculous exudates,
with diagnostic thresholds of 47IU/L.
 Sensitivities of ADA, for tuberculosis were
100%.
 Their specificities 91% and
 Their efficiencies 93%.

Pleural EffusPleural Effusionion
According to American College of Chest
Physicians journal CHEST, Specificity is
97% and sensitivity 100% when a value
of more than 45 U/L is considered.
In another article of the same journal it is
stated that The reliability of the early
diagnosis of pleural tuberculosis has
been greatly improved by the use of
adenosine deaminase (ADA) .

Adenosine Deaminase (ADA) Level inAdenosine Deaminase (ADA) Level in
Tubercular Pleural EffusionTubercular Pleural Effusion
 Determination of the ADA level in the
suspected pleural fluid appears to be the
most promising marker because of the ease,
rapidity, and cost-effectiveness of the ADA
assay . Sensitivity and specificity of elevated
level of ADA in the tuberculous pleural fluid
ranges from 91 to 100% .

 In Bangladesh a research regarding ADA as a
diagnostic tool was done by Department of
Medicine, National Institute of Disease of the
Chest and Hospital, Dhaka
 Department of Clinical Biochemistry, Lab
Medicine, Apollo Hospital, Dhaka, Bangladesh
 Department of Respiratory Medicine, Dhaka
Medical College, Dhaka

 This study has clearly shown that ADA levels
are significantly high in patients with
tubercular pleural effusion (68.7±37.0U/L)
compared to that (28.6±8.3 U/L) in non
tuberculous group.
 Sensitivity (94%) and specificity (88%) of the
test in tubercular pleural effusions when cut
off value set at 40U/L.

Value of adenosine deaminase (ADA) in asciticValue of adenosine deaminase (ADA) in ascitic
fluid for the diagnosis of tuberculous peritonitisfluid for the diagnosis of tuberculous peritonitis
 Tuberculous peritonitis remains a diagnostic
challenge for clinicians.
 Many studies have done for assessing the
usefulness of adenosine deaminase (ADA) in
ascites for the diagnosis of tuberculous
peritonitis.
 However, the overall diagnostic accuracy of ADA
for tuberculous peritonitis is given here
according to some authentic clinical research.

 According to a study result published in
Pubmed done on 2006 ADA levels showed
high sensitivity (100%) and specificity (97%)
using cut-off values from 36 to 40 IU/L.
Optimal cut-off point was determined at 39
IU/L.

 Another study in Sao Paolo in 1995 shows cut-off value of >
31 U/l, the sensitivity, specificity and positive and negative
predictive values were 100%, 92%, 72% and 100%,
respectively.
 They conclude that ADA determination in ascitic fluid is a
useful and reliable screening test for diagnosing tuberculous
ascites.
 Values of ADA higher than 31 U/l indicate more invasive
methods to confirm the diagnosis of tuberculosis.

 In European pub Med central journal Department of
Gastroenterology, M.L.N. Medical College, Uttar
Pradesh, India published that At a cut-off value
of greater than 33 U/L, the sensitivity, specificity,
positive and negative predictive value, and the
overall diagnostic accuracy for
diagnosing tuberculous ascites were
100%,96.6%,95%, 100% and 98% respectively.

 Another article in The Lancet Journal reviewed
ADA an asset for distinguishing tuberculosis from
other causes of ascites.
 The mean ADA activity was 45 U/L for patients
with Tuberculous ascites and 36.7 U/L in those
with other causes of ascites like alcoholic
cirrhosis, cryptogenic cirrhosis, malignant
disorders, pancreatitis and miscellaneous
causes.

In this study ADA has a sensitivity of
100% and specificity of 96%. These
studies suggest that the ascitic fluid
adenosine deaminase activity may be
used to identify patients in whom the
diagnosis of abdominal tuberculosis may
be pursued.

 Science Direct journal published their abstract
which was almost same.
 A cut-off level of 30 U/L for the diagnosis of
tuberculous peritonitis was found to yield the best
results; corresponding sensitivity and specificity was
94% and 92%, respectively.
 No statistically significant difference in ADA activity
was observed when tuberculous ascites occurred in
the absence or presence of cirrhosis.

Diagnostic value of adenosine deaminase inDiagnostic value of adenosine deaminase in
cerebrospinal fluid for tuberculous meningitiscerebrospinal fluid for tuberculous meningitis
 The diagnosis of TBM is complicated as it causes
various clinical manifestations, which overlap with
those of other chronic diseases of the central
nervous system (CNS) such as viral and pyogenic
meningitis.
 The initiation of anti TB medication in suspected
TBM patients can often be delayed because of a
lack of confidence in the presently available
laboratory tests .

 According to Oxford journal of infectious disease the
sensitivity of CSF ADA for diagnosing tuberculous
meningitis was 10.05 and specificity 99% .
 A significant rise in levels of enzyme was observed
during the first 10 days of therapy, was followed by a
gradual decline, and reached normal values after three
to four months of treatment.
 The test proved to be a simple and reliable method for
early diagnosis and follow-up of tuberculous meningitis.

 In a research of Biochemistry Research Laboratory,
Central India Institute of Medical Sciences,
demonstrated that ADA activity in the CSF of TBM
patients, using a cutoff value 11.39 U/L/min, can be
useful for the early differential diagnosis of TBM.
 This test can be performed in any pathology
laboratory where more sophisticated methods are
not available. The sensitivity of the test for positive
diagnosis was 82% and the specificity was 83%

 Department of Internal Medicine, Division of
Infectious Diseases, Asan Medical Centre, Ulsan
University College of Medicine, South Korea
studied an adenosine deaminase (ADA) activity in
the cerebrospinal fluid (CSF) and the result was
ADA activity >15 U/l could be a strong indication of
tuberculous meningitis and determination of CSF
ADA can aid in the early differential diagnosis of
tuberculous meningitis.

 The Journal of Tropical Medicine and Hygiene
reported Cerebrospinal fluid adenosine
deaminase levels differentiate
tuberculous meningitis cases from those
with aseptic meningitis being higher than
4 U/L in all and higher than 6 U/L in 90%
cases of tuberculous meningitis.

The Use of Adenosine Deaminase as DiagnosticThe Use of Adenosine Deaminase as Diagnostic
Tools for Tuberculous PericarditisTools for Tuberculous Pericarditis
 Traditional diagnostic tests for pericardial
tuberculosis (TB) are insensitive and often require
long culture periods, and this has led to more
emphasis being placed on biochemical tests such
as the pericardial adenosine deaminase (ADA) test.
 The median ADA level in the tuberculous group was
71.7 U/L (range, 10.3 to 303.6 U/L), which was
significantly higher than that in any other group like
malignancy, non tuberculous infections ,other
effusions, and effusions of uncertain origin.

The Use of Adenosine Deaminase as DiagnosticThe Use of Adenosine Deaminase as Diagnostic
Tools for Tuberculous PericarditisTools for Tuberculous Pericarditis
According to Europian Heart Journal, there was a
positive correlation between high adenosine
deaminase values and the development of
constrictive pericarditis. In this study, two patients
required pericardectomy. Therefore, the
adenosine deaminase value is a significant
prognostic indicator for the development of
constrictive pericarditis in tuberculous
pericarditis.

Diagnostic Value of Adenosine Deaminase inDiagnostic Value of Adenosine Deaminase in
Tuberculosis With HIV CoinfectionTuberculosis With HIV Coinfection
The global incidence of tuberculosis (TB)
has sharply increased, particularly in
areas where HIV and TB are both
prevalent. Tuberculous pleuritis (TBpl)
has been noted to be more common in
patients coinfected with HIV and TB than
in patients without HIV infection.

 Production of the enzyme Adenosine Deaminase in
pleural fluid reflects the presence of activated T
lymphocytes and monocytes. Therefore, it is
expected that ADA will be lower in HIV co-infected
patients and/or other immunocompromised patients
with low blood CD4 counts.
 ADA analysis is a sensitive marker of tuberculous
pleuritis even in HIV patients with very low CD4
counts in a high TB endemic region.

 According to CHEST journal the best cutoff at 60 U/L,
yielding measures for sensitivity (0.95), specificity (0.96),
positive predictive values (PPVs; 0.96), and negative
predictive values (0.95). the diagnostic value of ADAPF
is independent of HIV serologic status.
 According to PLOS ONE journal the cut-off value of ADA
30 U/L, the overall sensitivity, specificity, positive
likelihood ratio, and negative likelihood ratio of ADA was
94%, 95%, 19, and 0.06 respectively.

 The mean CD4 cell counts among TB pleuritis
patients were 29 and 153 cells/microL in patients
with CD4 <50 cells/microL and >50 cells/microL,
(p<0.05) respectively.
 The corresponding mean ADA values for these
patients were 76 U/L and 72 U/L respectively
(p>0.5). There was no correlation between ADA
values and CD4 cell counts (r = −0.120, p =
0.369).

 Even at CD4 counts of less than 10cells/microL,
the ADA values were still above the cut-off. they
also did not find any correlation between ADA
values and CD4 cell counts in another cohort of
South African HIV infected TB pleuritis patients .
 This may be due to higher immune activation in
HIV positive patients with very low CD4 counts .

 One explanation could be that the
isoenzyme ADA-2 which contributes
significantly to total ADA in diagnosing TPE
is found mainly in the monocytes which are
not significantly affected in HIV patients
compared to CD4 T-lymphocytes.

Serum and synovial fluid adenosine deaminaseSerum and synovial fluid adenosine deaminase
activity in patients with rheumatoid arthritis,activity in patients with rheumatoid arthritis,
osteoarthritis, and reactive arthritis.osteoarthritis, and reactive arthritis.
 A Research article of Eular journal assessed the value of
joint fluid ADA level in the diagnosis of synovial
swellings.
 Increased activity was found in the synovial fluid taken
from patients with rheumatoid disease and reactive
arthritis, though values were less raised in the later.
 Synovial fluid taken from patients with osteoarthritis did
not show significantly raised adenosine deaminase activity
as compared with that of normal controls

Serum adenosine deaminase activity in patientsSerum adenosine deaminase activity in patients
with systemic lupus erythematosuswith systemic lupus erythematosus
 In Systemic lupus erythematosus (SLE) Although
most infections are caused by Gram-positive or
Gram-negative bacteria, there is an increase in the
incidence of Mycobacterium tuberculosis and other
opportunistic infections.
 SLE and tuberculosis (TB) interact in complicated
ways - they may have similar presentation and may
mimic each other.

 Higher prevalence of tuberculous infections in
SLE is attributed to multiple immune
abnormalities that occur in these patients as well
as to immunosuppressive therapy.
 High doses of corticosteroids are also a major
risk factor. Also, uncontrolled hyperactivity of the
immune system actually makes SLE patients an
immunocompromised host.

 Resistance to MTB, which is mediated by cellular
immunity, is deficient in SLE patients both due to the
nature of the disease and the immunosuppressive
therapy.
 A Spanish study found that the incidence of TB was six-
fold higher in the SLE group compared to the general
population.
 Similarly, Hong Kong reported a five- to 15-fold higher
risk and from India, a 10-60-fold higher risk was
reported.

 Confirmation of clinical suspicion of TB is
hindered by several factors.
 TB presenting in a miliary pattern or with
mediastinal lymphadenopathy, or as extra-
pulmonary disease, poses a great diagnostic
challenge because these presentations may
point to a bacterial etiology or to other
diseases such as lymphomas.

 Also, extrapulmonary TB usually presents with
symptoms like persistent fever, arthralgia, arthritis,
anemia and pleural and pericardial effusion, which are
common in other diseases and may mimic SLE flares as
well.
 Because extrapulmonary involvement is more common
in SLE patients, it often requires tissue and body fluid
analysis for diagnosing TB and thus may take a longer
period to establish definitive diagnosis.

 Estimation of ADA levels in body fluids is a
valuable tool in establishing total TB. ADA
levels ≥42 IU/L are considered to be highly
suggestive of TB, with one study reporting a
sensitivity of 100%.

..
Serum adenosine deaminase activity and itsSerum adenosine deaminase activity and its
isoenzyme pattern in patients with systemic lupusisoenzyme pattern in patients with systemic lupus
erythematosuserythematosus
 Department of Connective Tissue Biochemistry,
University of Camerino, Italy. Published their
study in EUROPE PUBMED CENTRAL
JOURNAL about relation of ADA and SLE.
According to their study Serum tADA activity
was significantly increased in patients compared
to healthy controls (mean +/- SD; 476.9 +/- 145.3
vs 254.0 +/- 98.9 ncat/L, p < 0.001).

Serum adenosine deaminase activity andSerum adenosine deaminase activity and
its isoenzyme pattern in patients withits isoenzyme pattern in patients with
systemic lupus erythematosussystemic lupus erythematosus
 The isoenzyme analyses showed that the
increased total ADA activity in the patients
was mainly due to increased ADA2 activity
(371.3 +/- 154.8 vs 214.2 +/- 47.9 ncat/L in
healthy controls, p < 0.001). The mean
values for ADA1 activity in the patients (64.6
+/- 37.9 ncat/L) and healthy controls (69.2 +/-
26.9 ncat/L) were similar.

Serum adenosine deaminase activity and itsSerum adenosine deaminase activity and its
isoenzyme pattern in patients with systemic lupusisoenzyme pattern in patients with systemic lupus
erythematosuserythematosus
 A strong correlation was found between
serum ADA activity and disease activity as
measured by ECLAM (Spearman's rank
correlation coefficient 0.74, p < 0.0001, linear
regression coefficient 0.68, p < 0.01). Total
serum ADA activity (tADA) was measured
spectrophotometricall

summarysummary
 ADA Level in tuberculous pleural effusion ranged from
35-160 U/L with a mean level of 100U/L and sensitivity
and specificity of 100%.
 ADA level in tuberculous peritoneal effusion ranged
from 30-135 U/L with a mean level of 92U/L and
sensitivity and specificity of 100% and 95%.
 ADA level in tubercular pericardial effusion ranged from
63-117 U/L with a mean level of 90U/L and sensitivity
and specificity of 100% and 83.3% respectively.

Table 1. ADA level in serosal fluidTable 1. ADA level in serosal fluid..
Type Range (U/L) Mean (U/L)
Pleural
Fluid
Tuberculous 35-160 100
Non-
tuberculous
5-33 18
Peritoneal
Fluid
Non-
tuberculous
1-28 12
Pericardial
Fluid
Non-
tuberculous
1.5-29 15.33

Table 2.Table 2. Correlation of ada results with bacteriologicalCorrelation of ada results with bacteriological
results in pleural fluid, histopathology of biopsized pleuralresults in pleural fluid, histopathology of biopsized pleural
tissue and mt test among tuberculous pleural effusiontissue and mt test among tuberculous pleural effusion
cases, n = 62cases, n = 62
ADA in
pleural fluid
M/E for
AFB
Positive
Culture for
M. TB
Positive
Biopsy for
Granuloma
Positive
Tuberculin
Test
Positive
ADA Positive 6(10.34) 12(20.68) 27(46.55) 42(72.41)
ADA
Negative
n=4
0(0.00) 2(50.00) 0(0.00) 0(0.00)
Total
n=62
6(9.62) 14(22.50) 27(43.54) 42(67.74)

Table 3.Table 3. Comparison of Sensitivity, Specificity, Positive predictiveComparison of Sensitivity, Specificity, Positive predictive
value, Negative predictive value and Accuracy of ADA assay withvalue, Negative predictive value and Accuracy of ADA assay with
every parameter studied for diagnosis of TPEevery parameter studied for diagnosis of TPE
ADA
level
test Pleural
biopsy
Pleural fluid
culture for
M.TB
Pl
eural
fluid
AFB
Sputum
culture
for
Sputum
AFB
Sensitivity 0.94 0.68 0.44 0.23 0.10 0.15 0.10
Specificity 0.88 0.93 1.00 1.00 1.00 1.00 1.00
PPV 0.92 0.93 1.00 1.00 1.00 1.00 1.00
NPV 0.90 0.66 0.54 0.46 0.42 0.69 0.68
Accuracy 0.90 0.78 0.66 0.53 0.46 0.71 0.69

Table 4.Table 4. ADA results in pleural fluid among theADA results in pleural fluid among the
nontubercular pleural effusion cases, N = 41nontubercular pleural effusion cases, N = 41
Non
Tuberculous
Cases
Number of
cases
ADA Positive ADA Negative
Malignant n=30 3(10.0) 27(90.0)
Pneumonia n=8 1(12.5) 7(87.5)
Rheumatoid
Arthritis
n=1 1(100) 0(0.00)
Nephrotic
Syndrome
n=1 0(0.00) 1(100)
Congestive
Cardiac Failure
n=1 0(0.00) 1(100)
Total n-41 5(12.20) 36(87.80)

Table 5. The mean ADA values in theTable 5. The mean ADA values in the
different diagnostic category.different diagnostic category.
Case Mean ADA (U/L) +SD
Malignancy (N-26)* 12.9 +13.1
Congestive Heart Failure (N-
12)
7.16 + 6.2
Streptococcus Pneumoniae
Infection (N-1)
11
KlebsiellaPneumoniae
Empyema (N-1)
200
TotalTB Peuritis (N-197) 71.2 + 39.6
SD-Standard Deviation
*Kaposi’s Sarcoma is the only malignancy with the ADA of 73 above the cut
off

referencesreferences
 Pub Med.gov
 European PubMed Central
 CHEST journal
 Research Gate
 Lung India
 European Respiratory Journal
 BioMed Central
 Journal of Internal Medicine (JIM)
 PLOS ONE
 Science Direct Journal
 The Eular Journal
 SAGE Journal

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