Laboratory services function at the cross cutting interface of all other divisions like Basic Services (ICTC), Care, Support and Treatment (ART), Blood Transfusion Services and Sexually Transmitted Infection division.The assurance of quality in HIV testing services is ensured  through the implementation  of  External Quality Assessment Scheme (EQAS) by Reference laboratories at Both National and State level.

In TamilNadu, 3 National Reference Laboratories (NRL) and 12 State Reference Laboratories (SRL) are interlinked with all HIV Testing Facilities (ICTCs)  of  32 Districts. Two NRLs and Five SRLs were accredited by National Accreditation Board for Testing and Calibration Laboratories (NABL).  NACO supports all the reference laboratories to get NABL Accreditation.

There are 32 CD4 testing Facilities are functioning in the state and 3 type of CD4 machines available such FACS Calibur -3 ; FACS Count -21 and Partec in 8 numbers. National Institute for Research in Tuberculosis Chennai functioning as  Viral Load Testing centre and Early Infant Diagnosis  (EID) Testing Lab for the state.In TamilNadu, Madras Medical College, Chennai is the referral lab for HIV 2 Diagnosis.

Key functions of  SRLs :

Monitor Laboratory Performance and evaluate Quality control measures.
Promote High Standards of Good Laboratory Practices.
Conduct Training for Lab technicians through EQAS Workshops and Refresher Trainings.
SRLs crosschecking the test samples from ICTCs which will include 20% of all positive samples and 5% of all negative samples collected in the first week of every quarter (January, April, July and October).

S.NoName of the SRLLinked Districts
1Stanley Medical College, ChennaiChennai, Tiruvallur
2Govt Hosp. for Thoracic Medicine,Tambaram, Kancheepuram DistKancheepuram, Vellore
3Chengalpattu Medical College,
Kancheepuram Dist
Cuddalore, Tiruvannamalai, Villupuram
4Coimbatore Medical College, CoimbatoreCoimbatore, Tirupur, Erode & Nilgiris
5Govt. M K Medical College, SalemSalem,Dharmapuri,Krishnagiri
6Madurai Medical College, MaduraiMadurai, Pudukkottai
7K A P Viswanathan Govt Medical college, TrichyTrichy, Perambalur, Ariyalur, Namakkal
8Thanjavur Medical College, ThanjavurThanjauvr, Tiruvarur, Nagapattinam
9Govt. Medical College, TheniTheni,Karur,Dindigul
10Tirunelveli Medical College, TirunelveliTirunelveli, Virdhunagar
11Govt. Medical College,ThoothukudiThoothukudi, Sivagangai
12Kanyakumari Medical College, NagercoilKanniyakumari, Ramanathapuram
S.NoName of the NRLLinked SRLs
1Madras Medical College, ChennaiMadurai, Theni, Tambaram, Chengalpattu, Chennai, Thanjauvr, Coimbatore
2Tamil Nadu Dr.MGR Medical University, ChennaiTrichy, Kanniyakumari,Salem, Thoothkudi, Tirunelveli & Pondicherry JIPMER
3CMC VelloreKerala State (Medical Colleges of Thiruvananthapuram, Allapuzza, Kottayam, Thrissur and Kozhikode)