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21. General Practice

WoSSVC GP Information Poster

Chickenpox/shingles exposure in pregnant or immunocompromised patients

Sexually Transmitted Infections in Primary Care - Second Edition 2013

NHS Guidance on Testing, Diagnosis and Referral Of Bloodborne Viruses

Sandyford Initiative protocols (inc. Chlamydia, Genital Herpes, Gonorrhoea, Hepatitis A/B/C, HIV Testing and Risk Reduction, HSV, molluscum contagiosum, post-exposure prophylaxis, post-exposure prophylaxis sexual exposure, syphilis, warts (human papillomavirus).

For all virology testing requiring an EDTA blood sample please use a 9mL tube (e.g. Vacuette tube 9mL K3E K3EDTA - lavender cap).

The WoSSVC have to spin the blood bottle to pull the cells to the bottom and remove the plasma (the cell free fluid) which is used for testing. A minimum of half of the blood volume is made up of cells and is unable to be used by the laboratory. If a patient has a positive screening result we need to do multiple confirmation tests. You will get results if you send us a small EDTA sample, but they may not be complete. In this case a repeat sample would be required in order to confirm or exclude a current infection. If a 9mL EDTA blood is received the WoSSVC can confirm co-infections with two blood-borne viruses without the need for the patient to return to the practice for more blood to be taken. Please note we will not accept two small samples. We do not have the staff available to cope with double samples and the second bottle will not be processed. One 9mL or one 5mL sample should be provided. If a 5mL is provided, the patient may not receive results without a second submission.

GP electronic request (ICE / EMIS / Vision) items

Items names:

  • Acute Hepatitis testing
  • Anti-HBc IgG-past natural HBV infection
  • Anti-HBs-post HBV immunisation
  • Anti-Streptolysin O (ASO)
  • Chlamydia/Gonorrhoea PCR - Pharyngeal
  • Chlamydia/Gonorrhoea PCR - Rectal
  • Chlamydia/Gonorrhoea PCR - Urine
  • Chlamydia/Gonorrhoea PCR - Vulvovaginal
  • Chronic Hepatitis testing
  • Coxiella burnetii Serol (Q fever)
  • Cytomegalovirus IgM - acute CMV
  • Epstein Barr virus IgM - acute EBV
  • Eye PCR - HSV VZV adenovirus Chlamydia
  • Eye PCR - Neisseria gonorrhoeae
  • Helicobacter Serology (N+S)
  • Hepatitis A virus IgG - past HAV
  • Hepatitis B screen (HBsAg)-current HBV
  • HIV antibody/antigen (Ab/Ag) screen
  • HSV / syphilis PCR - Genital ulcer
  • HSV/VZV PCR - Non-genital ulcer/vesicle
  • Leptospira Serology
  • Maculopapular rash PCR-current infection
  • Measles / rubella PCR -current infection
  • Measles IgG - past natural infection
  • Mumps PCR - current infection
  • Mycology Dermatophytes #1/2/3/4
  • Norovirus PCR - Faeces
  • Norovirus PCR - Rectal Swab
  • Norovirus PCR - Vomit
  • Other virology requests
  • Parvovirus B19 IgG - past infection
  • Parvovirus B19 IgM - acute infection
  • Rubella virus IgG - past infection/vacc.
  • Syphilis serology screen - blood
  • Toxoplasma IgG screen
  • Varicella zoster virus IgG - past VZV
  • Viral Diarrhoea PCR (not noro)-Faeces
  • Viral Diarrhoea PCR (not noro)-Rectal
  • Viruses+Mycoplasma+Pertussis Gargle
  • Viruses+Mycoplasma+Pertussis Sputum
  • Viruses+Mycoplasma+Pertussis Throat Swab

Chlamydia trachomatis and Neisseria gonorrhoeae testing

Primary Care Guidelines for Chlamydia Testing in NHS GG&C

Summary

  • Confine testing for chlamydial infection to symptomatic patients.
  • Avoid opportunistic testing in the absence of relevant clinical indications i.e. avoid testing during smear tests and other routine procedures, unless there are clear clinical reasons.
  • Asymptomatic patients can be tested for Chlamydial infection in the context of a request for a comprehensive sexual health screen because of concern about sexual risk.

Self-collected vulvovaginal swabs are the sample of choice (have the highest sensitivity) for both chlamydia and gonorrhoea testing in women, regardless of whether patients have symptoms. Endocervical swabs are no longer recommended for chlamydia and gonorrhoea testing due to their reduced sensitivity compared to vulvovaginal swabs. Urine is not a suitable sample type due to insufficient sensitivity.

Please see:

Schoeman SA, Stewart CM, Booth RA, et al. Assessment of best single sample for finding chlamydia in women with and without symptoms: a diagnostic test study. BMJ. 2012;345:e8013.

Stewart CM, Schoeman SA, Booth RA, et al. Assessment of self taken swabs versus clinician taken swab cultures for diagnosing gonorrhoea in women: single centre, diagnostic accuracy study. BMJ. 2012;345:e8107.

Hepatitis C virus (HCV) diagnosis: Abbott ARCHITECT® HCV antigen (Ag) test

Routine diagnosis of HCV infection is based on the detection of HCV IgG antibodies (evidence of infection in the past, but not current infection) and if HCV antibody positive, testing for the HCV RNA genome. HCV IgG antibody is positive in on-going active infection and a recovered infection (via natural clearance or treatment). HCV IgG antibody is negative in the window of 45-68 days between HCV infection and seroconversion to HCV IgG. HCV RNA (by polymerase chain reaction, PCR) provides the diagnosis of an on-going, active HCV infection. PCR assays are expensive, involve considerable technical skill and are labour-intensive. The Abbott ARCHITECT HCV antigen (Ag) assay detects a viral protein which surrounds the RNA genome. The test is less expensive and less time-consuming than PCR and identifies current HCV infection. In the same way that hepatitis B surface antigen (HBsAg) is used to test for current infection with hepatitis B, HCV antigen tests for current infection with hepatitis C. The Abbott ARCHITECT HCV antigen assay is not as sensitive as PCR for current infection. The sensitivity of the Architect HCV-Ag assay is reported to be 428 - 2,700 IU/mL HCV RNA, depending on the HCV genotype. In HCV antibody positive, HCV antigen negative samples, a single PCR test will be performed, if not previously tested to exclude low level viraemia.