TY  - CHAP
M1  - Book, Section
TI  - Diseases & Pathophysiology in Rheumatology
A1  - Huppert, Laura A.
A1  - Dyster, Timothy G.
Y1  - 2021
N1  - 
T2  - Huppert’s Notes: Pathophysiology and Clinical Pearls for Internal Medicine
AB  - Rheumatologic  conditions  associated  with  a  +ANA:Systemic  lupus  erythematosus  (SLE)Systemic  sclerosis  (SSc)Myositis  (often  ANA-negative;  ~50%  of  dermatomyositis/polymyositis  cases  are  ANA-positive)Mixed  connective  tissue  disease  (MCTD)Primary  Sjögren’sANA  Testing  Pearls:-  Antinuclear  antibodies  (ANA)  are  autoantibodies  that  bind  to  the  contents  of  the  cell  nucleus.  The  ANA  test  detects  the  ANA  autoantibodies  that  are  present  in  the  patient’s  serum.-  ANA  can  be  elevated  in  many  disorders  including  autoimmune  conditions,  infection,  and  malignancy.  20%  of  healthy  women  have  a  positive  ANA.  Therefore,  it  is  non-specific  and  should  only  be  sent  if  clinical  suspicion  is  high  for  one  of  the  disorders  above.-  The  level  of  autoantibody  is  reported  as  a  titer,  which  is  the  highest  dilution  of  the  serum  at  which  the  autoantibodies  are  still  detectable  (e.g.,  1:640  is  more  dilute  than  1:80,  suggesting  more  autoantibodies  are  present  in  the  1:640  sample).  The  probability  of  autoimmunity  increases  with  higher  ANA  titers:ANA  ≥1:80  required  by  EULAR/ACR  SLE  classification  criteriaANA  ≥1:640  →  95.8%  specific  for  SLE-  If  an  ELISA-based  ANA  test  is  negative  but  clinical  suspicion  for  CTD  high,  ask  the  lab  to  carry  out  an  immunofluorescence  (IF)-microscopy-based  ANA  test,  which  is  more  specific.  
SN  - 
PB  - McGraw Hill
CY  - New York, NY
Y2  - 2024/04/16
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1189914044
ER  -