Examination requirements for selected clinical questions

In some clinical pictures, a large number of pathogens come into question due to complex differential diagnostic possibilities.
For reasons of time and technical procedure and economic efficiency, not all possible pathogens can always be considered from the outset when determining the scope of the examination. Moreover, since the positive predictive value of each examination decreases in collectives with a low prevalence of the respective infection, untargeted "screening" is not only expensive, but often also unhelpful or even misleading.
The selection of examination requirements should be based on what is common on the basis of epidemiological data and also take into account special features of the individual case (e.g. immunosuppression, Z.n. surgery, stay abroad). Only if the results obtained first do not allow a diagnosis to be made should the scope of examinations be extended to include other, rarer infections.
The following compilations are intended to provide help for the sensible selection of examinations for common clinical questions or to clarify which examinations are initially performed in the case of unspecified requirements depending on clinical information and examination material.

  • Pneumonia
  • Meningitis
  • Joint infections
  • Myocarditis
  • Enteritis
  • Hepatitis

The epidemiological situation in Germany was taken into account. In individual cases, it may be necessary to include other infections not mentioned here in the differential diagnosis.
Material for examinations that are not performed at our institute may be forwarded by us to a suitable external laboratory. If you have any questions, please do not hesitate to contact the physicians and academic staff of our institute.

Abbreviations:

  • AK = Antibody
  • AG = antigen
  • PCR = Polymerase Chain Reaction

PNEUMONY

The distinction made here between lobar or bronchopeumonia and atypical pneumonia should not be considered absolute.

Lobar or bronchopneumonia

In all patients, examination of respiratory secretions, blood cultures if necessary: general bacteriological culture.

In patients with severe underlying disease/immunosuppression and/or prolonged antibiotic therapy or prolonged hospitalization additionally:

Legionella culture (supplemented by Legionella antigen test from urine, if necessary)

In addition, if there is appropriate clinical and/or epidemiological evidence:

 

  • Tuberculosis (culture and microscopy, genome detection) if necessary Qantiferon test
  • mycological examinations (e.g. dimorphic fungi during stays in non-European countries Pneumocystis jirovecii in patients with severe cellular immunodeficiency (PCR, various stains)
  • Pertussis (Bordetella pertussis; direct detection from nasopharyngeal swab (PCR), antibody detection from serum IgM, IgA, IgG)

Atypical pneumonia


Serological examination (antibody determination from serum) in all patients:

  • Chlamydia pneumoniae AK (serum) IgM, IgA, Ig
  • Chlamydia psittaci AK (serum) KBR
  • Mycoplasma pneumoniae (serum) IgM, IgA, IgG
  • Coxiella AK (serum) CFT
  • Legionella pneumophila (serum) IgG

If viral pneumonia is suspected: direct detection from respiratory secretions as a screening test or single determination:

  • Adenovirus (IFT)
  • Influenza A viruses (IFT, PCR, AG)
  • Influenza B viruses (IFT, AG)
  • New influenza H1N1(PCR)
  • Parainfluenza 1-3 viruses (IFT)
  • RS Viruses (IFT, AG
  • SARS CoV2 (PCR)

Multiplex PCR (Pneumonia Panel)

If the described standard methods do not lead to a sufficient diagnosis, further multiplex PCR is available for supplementary pneumonia diagnostics.

MENINGITIS 

Acute "bacterial" meningitis

In all patients with suspected primary meningitis: general bacteriological examination of CSF and blood cultures; if necessary, antigen detection of meningitis pathogens in CSF. In case of negative culture results: universal (16S rDNA) PCR for bacteria in CSF. In immunocompromised patients: additional mycological examination of CSF, including examination for Cryptococcus neoformans.

Secondary "bacterial" meninigits (e.g., after neurosurgical operation):

General bacteriological and mycological examination of cerebrospinal fluid, blood cultures and wound secretions if necessary.

"Serous" meningitis

Examination of cerebrospinal fluid in all patients:

  • General bacteriological
  • Borrelia (AK detection in serum and, if necessary, CSF) (especially in the case of CSF lymphopleocytosis), if necessary Borrelia PCR.
  • In case of negative culture results, possibly additional: universal (16S rDNA) PCR for bacteria.

In addition, if there is appropriate clinical and/or epidemiological evidence:

Lues (Ak detection in serum and CSF, if necessary) Tuberculosis (culture and microscopy, possibly PCR) M. Whipple (external PCR)

In immunosuppressed patientsAdditional:

Mycological examination, including examination for Cryptococcus neoformans toxoplasmosis (PCR;AK determination in serum and, if necessary, CSF.
If viral infection is suspected, examination of CSF with PCR for:
HSV
VZV
Enteroviruses
Further viral diagnostics after consultation

Multiplex PCR (Meningitis Panel)

If the described standard methods do not lead to a sufficient diagnosis, further multiplex PCR is available for supplementary meningitis diagnostics. 

BONE AND JOINT INFECTIONS 

In all patients, examination of joint punctates, tissue or similar:

  • general bacteriological and mycological examination (microscopy, culture) 

In case of negative culture results, possibly additionally:

  • universal PCR on bacteria (16S rRNA)

 In addition, if there is appropriate clinical and/or epidemiological evidence:

  • Tuberculosis (microscopy, culture, genome detection)
  • Serological pathogen detection (antibody determination from serum):
  • Borrelia burgdorferi (IgG, IgM)
  • Campylobacter (IgG, IgA)
  • Chlamydophilia pneumoniae (IgG, IgM, IgA)
  • Chlamydia trachomatis (IgG, IgM, IgA)
  • Chlamydophilia psittaci (AK-general)
  • Mycoplasma (IgG, IgM, IgA)
  • Yersinia (IgG, IgA)
  • Treponema pallidum (TPPA, VDRL, IgM and IgG immunoblot)
  • Streptococci (ASL, ADNas

MYOCARDITIS

Serological pathogen detection (antibody determination from serum):

  • Adenoviruses (IgG, IgA)
  • Coxsackie viruses (IgG, IgA)
  • ECHO viruses (IgG,IgA)
  • Cytomegaloviruses (IgG, IgM)
  • Epstein-Barr viruses (VCA IgG, VCA IgM, EBNA-1 IgG)
  • Mumps viruses (IgG, IgM)
  • Parvovirus B19 (IgG, IgM)
  • Influenza A Virus (IgG, IgM)
  • Influenza B Virus (IgG, IgM)

Genome detection (PCR from biopsies):

  • Enteroviruses
  • Coxsackie viruses
  • ECHO Viruses
Further virus diagnostics after consultation.

ENTERITIS

Culture detection from stool (intestinal pathogens):

  • Campylobacter
  • Salmonella
  • Shigella
  • Yersinia

 If necessary, specific request or after consultation:

  • Clostridioides difficile (AG, toxin from stool if necessary)
  • Adeno-/Rotaviruses (PCR, AG from stool)
  • Noro viruses (PCR, AG from stool)
  • Vibrio cholerae (culture from stool)
  • Enterohaemorrhagic E. coli (EHEC)

VIRAL HEPATITIS

Hepatitis A

  • anti-HAV total, anti HAV IgM
  • HAV antigen in stool, if applicable

Hepatitis B

  • HBsAG, anti-HBs, anti-HBc total,
  • anti-HBc IgM, HBe antigen, anti-HBe, anti-Delta, if applicable
  • Hepatitis B PCR

Hepatitis C

  • anti-HCVtotal
  • If necessary, hepatitis C RT-PCR and genotype determination

Hepatitis E

  • anti-HEV IgG
  •  anti-HEV IgM

In addition to the specific hepatitis viruses, infections caused by herpes viruses (e.g. CMV, EBV), etc. should also be considered. Routine examination program after cannula bite injury or similar:

  1. Donor: HBsAG, anti-HBc, anti-HCV, HIV-AG-AK-combo test if necessary PCR
  2. Recipient: anti-HBc, anti-HBs, anti-HCV, HIV-AG-AK combo test
  3. Emergency screening for needlestick injuries is available 24/7.

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