CHAPTER 3: DIAGNOSIS
Diagnosis and treatment is one of the key tasks
required to tackle infection and involves a wide variety of health
professionals and scientists. Diagnosis and treatment is necessary
for care of individuals but also can inform control measures and
preventative activity (see chapter 4).
We are concerned that there is a shortage of infectious
disease experts able to diagnose unusual infection. In addition,
we have found that training in infectious disease of health professionals
who are not infection specialists is insufficient to enable effective
diagnosis and treatment to take place at all times. Laboratory
scientists able to exploit new sophisticated techniques are also
in short supply.
3.1 The management of infection in an individual
firstly requires a symptom-based diagnosis; this may be supported
by laboratory investigations which identify the infectious micro-organism
[Wright II, p56]. Knowledge of the infection will guide any intervention
and treatment. Some infections, particularly viral infections,
the common cold for example, cannot be effectively treated but
symptoms can be managed until the patient's immune system has
fought off the infection.
3.2 Doctors are the primary players involved in diagnosing
and treating infection with support from laboratory scientists
who identify the responsible micro-organisms [Little, II Q414].
Nurses also increasingly have a role in identifying patients with
infections: they staff NHS Direct (a telephone and web-based advice
service accessible to the public) [Beeching, Q122; PHLS Prim Care
Ad Gp, I p131; Howard, Little, Perry, Williams, Q409-12]. In addition
people manage much simple infection (such as the common cold)
without resorting to advice from health services although they
sometimes consult a pharmacist [Little, Q371].
3.3 General Practitioners (GPs) diagnose and treat
the majority of infection that comes to the attention of the health
services: patients with an infection account for forty percent
of consultations [see Box 2; Stewart, II p316].
3.4 We heard throughout this inquiry, including from
some GPs, that GPs receive inadequate training about best practices
relating to identifying and treating infection. There are particular
concerns that GPs do not use laboratories effectively enough [Little,
Q407-8; Wiltshire Food Liaison Grp, I p171; Birmingham, II p394].
diagnosis on symptoms or laboratory
3.5 GPs are sufficiently familiar with common infections
in their local area to be able to diagnose and manage an infection
on the basis of symptoms in most cases. Diagnosing on the basis
of symptoms has advantages in that it is often accurate, is quick
and may occur on the basis of one consultation [Little, Q403].
An alternative method would be to take a sample (such as a throat
swab) and send it to a laboratory to identify the underlying micro-organism;
using this method would not, in most cases, result in different
advice about treatment for common infection.
3.6 Sending samples off for laboratory investigation
is often time-consuming. Results may take several days, depending
on the type of micro-organism, by which time the patient could
have fought off the infection [Duerden, Q283]. As patients are
often unhappy to return home without a prescription, the GP might
deem it necessary to provide some treatment for the patient whilst
awaiting laboratory results. It is arguable whether, even if GPs
did send more samples to laboratories, there are sufficient resources
to cope with extra demand. Thus, sending samples to laboratories
for most cases of common infection could increase burden on laboratories
without, in the majority of cases, improving patient care [Little,
3.7 Laboratory diagnosis is however vital to identifying
and therefore treating serious infection. We heard that sending
samples to laboratories is useful as it can inform doctors about
what treatment regime to recommend. This then benefits the patient
by reducing the length and severity of illness [Assoc Brit Pharm
Industry, I p11; Haworth, I p75; Roche Diags, I p140-3]. In addition,
we heard that microbiological diagnosis contributes to a body
of knowledge about infection which can be used for prevention
purposes [see chapter 4].
3.8 The Institute of Medicine in the United States
of America recently warned against reducing use of laboratory
investigations, particularly in the case of infection treated
Identifying the exact micro-organism can guide the doctor about
the most appropriate antibiotic to prescribe. This prevents treating
with a "broad spectrum" or antibiotic which contributes
to continuing and worrying increases in antibiotic resistance
[Spec Ad Cttee Antimicrobial Resistance, I p159].
3.9 We heard about the importance of diagnosing viral
infections. Correct diagnosis of viruses can also help to reduce
inappropriate treatment with antibiotics (as antibiotics are ineffective
against viral infections). As new anti-viral treatments become
available it may be important to ensure appropriate use of such
treatments in order to prevent resistance to those drugs developing.
There is a shortage of experts in this area (virology, a sub-set
of microbiology) [Clin Virol Network, II p90; Pillay, Q180].
3.10 Gathering information from laboratory investigation
and using to alongside information about symptoms of disease can
help to develop best practice guidelines about treating on the
basis of syndromes alone (thus saving on laboratory testing in
the future) [Black, I p28-33; Little, Q376].
3.11 One way of ensuring that treatment and management
is informed by knowledge of the micro-organism is to further develop
and use "near patient" diagnostic tests (NPTs). These
can produce results straight away and can also be used within
the general practice [PHLS Prim Care Ad Gp, I p132].
3.12 There is a certain degree of caution expressed
about NPTs. The cost of new diagnostics is significant and we
heard that quality control issues have not been sufficiently well
addressed. In particular, it is not known what conditions must
be met outside of a laboratory setting to ensure reliability [CAMR,
I p42; Roche Diags, I p142; PHLS Prim Care Ad Gp, I p132]. Also,
increasing use of NPTs could reduce further collecting of information
for public health use [Boriello, Q492; PHLS, II p139].
3.13 NPTs provide good opportunities to improve diagnosis
and treatment, but there should be further research into their
effectiveness and their impact on public health. We discuss the
importance of such research in chapter 8.
nurses: tracing people in the community
3.14 Community infection control nurses (CICNs) play
a significant role in identifying people with infection and in
ensuring that they receive treatment. For example, specialist
tuberculosis (TB) CICNs identify people at increased risk of TB
and ensure that they are diagnosed and treated if necessary [Williams,
Q411; Birmingham, II p395]. Many CICNs also fulfil other roles,
including implementing infection prevention strategies [Perry,
3.15 We heard that there are enormous disparities
in community based infection control across the country: a recent
PHLS study found that the ratio of CICNs to head of population
ranged from 0 to 4.5 whole time equivalent CICNs per 500,000 population
[Inf Control Nurses Assoc II p176]. There are particularly serious
gaps in expertise in contact tracing for TB in some areas of the
country [Birmingham, II p395].
3.16 The shortage of information about individuals
who are at increased risk of infection was cited as being a barrier
to effective contact tracing. Ms Crisp, a CICN, described how
information about people's country of origin for all new immigrant
arrivals was not made available to CICNs. This information is
vital to identifying those most likely to have been exposed to
TB and being able to treat appropriately [Birmingham, II p395].
3.17 Infectious disease may be exacerbated in individuals
who live in poor social conditions. Such individuals often find
it difficult or are unwilling to use conventional means of health
care advice, which makes it hard to identify and manage infection
in these groups. The Felton TB centre in Harlem, New York recognises
this and employs outreach workers to work with local churches
and alternative therapists in order to better identify and treat
people with both latent and active TB
[US, II p390]. We heard that similar tactics in England might
help to follow up people who did not turn up for appointments
at TB clinics [Birmingham, II p395]. Mrs Gini Williams, a TB Research
Nurse at City University, recommends adopting "a whole systems
approach" where treatment is not viewed simply as medical
but also considers housing and social circumstances and human
behaviour, as this could help to improve the effectiveness of
medical treatment and prevent recurrence of infection [II p196-204].
Considering adopting such techniques is particularly important
given recent significant increases in TB [Williams, Q386].
3.18 Within hospitals there are a range of specialists
who are responsible for diagnosis and treatment of patients with
infection. A number of skills are required, but in particular
there is need for abilities to
out clinical diagnosis and manage a range of infections; and to
laboratory diagnosis and translate this understanding to bedside
3.19 At present many general and specialist doctors
diagnose and manage infection. For example, a chest physician
may care for a patient with TB and a renal physician may care
for a patient with a kidney infection. Non-infection specialists
are, with laboratory support, able to care for infections in many
cases. However, we heard that knowledge about diagnosing and managing
unusual infection amongst non-infection specialists was limited
[Beeching, Finch Q88].
3.20 There are also around 80 infectious disease
(ID) physicians in England, mostly located in teaching hospitals.
They care for patients with severe or complex infectious disease
problems [Beeching, Q121]. Most doctors rely on such specialists
to look after unusual infections. However, there was some concern
that there were insufficient numbers of such specialists [Beeching,
3.21 We heard that there are more doctors entering
training to become infectious disease physicians than there are
available posts and they have little presence in district general
hospitals. The number of ID physicians in England appears to be
low, currently at 1 per 750,000 people (in the USA there is approximately
1 per 53,000) [www.idsociety.org]. The Netherlands, where the
structure relating to microbiologists and infectious disease physicians
is comparable to England, has 1 per 250,000 people. [Beeching,
Q121; DoH, II p32].
3.22 The use of laboratory diagnosis in the hospital
is normal, partly because of the risk of serious infection and
because there is an increased risk that infection will spread
to other patients. Medical microbiologists, along with laboratory
scientists supply this service. They also act as a link between
the laboratory and the bedside, providing advice to non-infection
specialists on treatment and control.
3.23 We also heard that there are insufficient numbers
of doctors with both laboratory and clinical skills. We are concerned
that despite a number of initiatives to encourage and nurture
clinical microbiologists they continue to be in short supply with
posts remaining unfilled [Prof Amyes, I 2; AcMedSci Q43, 46, II
p36; MRC and Wellcome Trust Q736; Resistance to antibiotics].
3.24 Sophisticated laboratory techniques are increasing,
particularly with the advent of molecular technologies. These
could be used in microbiology laboratories to improve rapidity
and accuracy of diagnosis [Amyes, I p1-3; Assoc Brit Pharma Industry,
I p11]. For example, molecular techniques can be used to understand
the spread of infection or a problem such as anti-microbial resistance
by tracking individual clones of bacteria through human populations
[Amyes, I p2].
3.25 Many laboratories still use techniques that
are outdated and less reliable or informative, as there is a shortage
of scientists and medical microbiologists with the necessary expertise
to have confidence to use them [Amyes, I p2; Pub Health Med Env
Grp, I p114].
3.26 There is shortage of expertise in both primary
and secondary care in identifying and managing unusual infection
and in being able to understand laboratory diagnosis and manage
clinically. In addition, laboratory expertise needs to be developed
in order to benefit from advances in diagnostic technologies.
We make recommendations in chapter 7 on training and chapter 8
on research and development.
3.27 We also conclude that there should be better
understanding of how organisation of services, social issues and
human behaviour impact on diagnosis and treatment outcomes. We
discuss this further in chapter 8.
10 Smolinski, Hamburg and Lederberg (eds). Microbial
Threats to Health: Emergence, Detection, and Response. Institute
of Medicine Committee on Emerging Microbial Threats to Health
in the 21st Century. [www.iom.edu] Back
Latent TB is where someone is infected with TB bacteria but has
fought it sufficiently to prevent it from causing symptoms. People
with latent TB cannot spread TB to others and do not feel ill
but it can develop into active TB at a later stage. When active
TB causes illness and may spread to others. Back