Surgical Science, 2011, 2, 89-94
doi:10.4236/ss.2011.22019 Published Online April 2011 (
Copyright © 2011 SciRes. SS
The Use of Biochemical Parameters as Nutritional
Screening Tools in Surgical Patients
Indraneil Basu, Padmanabhan Subramanian, Matthew Prime, Charlie Jowett, Brian Levack
Queens Hospital, Romford, Essex, RM7 0AG
Received January 30, 2011; revised February 27, 2011; accepted Ma rch 20, 2011
Nutritional status influences surgical outcome and complication rates. The National Institute of Clinical Ex-
cellence, (NICE) recommends screening patients on admission; yet traditional nutritional screening tools are
underutilised. This retrospective case-control study investigates the association between biochemical factors
and adverse outcomes in orthopaedic patients to ascertain whether they could provide more suitable alterna-
tives to traditional screening tools. 66 patients with fractured neck of femur were investigated. Adverse out-
comes including Length of Stay, (LOS), and deaths were recorded. Total Lymphocyte Counts, (TLC), Serum
Albumin Levels and Haemoglobin levels, were recorded pre-operatively, (pre-op) and post-operatively,
(post-op). Adverse outcomes in those with normal and abnormal biochemical values were compared using
Chi Squared and T Testing. Linear associations were tested for using Pearson rank correlation. Automated
Nutrition Scores Beta, (ANSB) were calculated and their relationship to adverse outcomes investigated. Pro-
tein energy malnutrition was common on admission. However, only 2 patients were nutritionally screened
during admission. Those patients with abnormal pre-op TLC had an increased LOS in hospital. Those with
abnormal albumin and/or TLC had increased mortality rates. Abnormal albumin levels were associated with
a significant 3 fold increase in mortality, (p = 0.009) and post-operative TLC were found to be negatively
correlated with LOS, (r = –0.3, p = 0.038). ANSB were also found to correlate with increased adverse out-
comes although this was not significant. This study demonstrates that nutritional status is poorly assessed on
admission in orthopaedic patients and consequently that provision of nutritional supplements is suboptimal.
This study also demonstrates a highly significant relationship between abnormal albumin and adverse out-
comes and identifies a new correlation between post-operative TLC and LOS. This study confirms that indi-
vidual biochemical parameters and biochemical scores can be used to identify orthopaedic patients at par-
ticular risk of adverse post-op outcomes. These biochemical screening methods may be a more efficient and
reliable way of stratifying malnutrition associated risk on admission.
Keywords: Nutrition, MUST, Mortality, Lymphocyte Count, Albumin, ANS Beta
1. Introduction
Malnutrition in elderly patients has long been recognised
as a predictor of poor clinical outcome. Poor nutritional
status has been identified as a causative factor in sus-
taining fractures [1]. Protein-energy malnutrition has also
been associated with increased post-op complications
including delayed wound healing, infections, decubitus
ulcers and increased mortality [2,3]. Conversely im-
proved nutrition has been shown to protect against geri-
atric trauma [4].
There is a large body of evidence emphasising the
importance of recognising poor nutritional status in hos-
pitalised patients early and addressing it appropriately.
NICE guidelines recommend screening for poor nutri-
tional status on admission facilitating appropriate provi-
sion of nutritional supplementation throughout the ad-
mission. The gold standard of nutritional assessment is
the Subjective global assessment, (SGA) tool which is
both involved and, open to interpretation based inconsis-
tencies. It is infrequently taught during medical educa-
tion and less frequently used on hospital wards. More
simple screening tools are available for use on admission
and are frequently included in admission clerking pro-
formas. One such tool being the Malnutrition Universal
Screening Tool, (MUST) which highlights those at risk
of malnutrition associated complications. Despite rec-
ommendations and tools being in place, assessments and
screening tools remain notoriously underutilised and
provision of supplementation is generally poor [5]. The
cause for such poor compliance with such tools is un-
clear, but the involved na ture of the validated assessment
tools and the need to frequently involve other healthcare
professionals to screen and assess patients and to provide
supplementation is partly to blame.
Simple biochemical markers including albumin levels
and TLC have long been regarded as markers which can
reflect the risk of malnutrition related complications and
provide simple means of screening for those at risk [2,3,
6-10]. However, use of these markers as indicators of
nutritional status is controversial. There is debate as to
whether abnormal biochemical factors are reflective of
poor nutritional status or whether they simply reflect the
physiological severity of illness. Most acute illnesses
increase the physiological demand on the body and
therefore increase the nutritional requirement of the pa-
tient. Biochemical factors and nutritional status are
therefore intricately related. Complex biochemical as-
sessment tools have been validated and used pre-op to
allocate appropriate nutritional su pport to at risk patients
and have been shown to reduce post-op mortality [11].
Simple biochemical assessment tools have also been
validated against the SGA tool and have been shown to
identify those at risk of malnutrition related complica-
tions [12]. Biochemical factors can therefore reflect
malnutrition associated risk. Whether their role is as a
surrogate or as a direct marker of nutritional status re-
mains unclear. Few validated biochemical systems of
nutritional screening are encouraged in clinical practice
and as a consequence, these important factors are over-
looked in spite of evidence to the contrary. In light of
such poor compliance with traditional screening tools
biochemical markers could provide a simple and effec-
tive alternative which may allow us to identify those at
risk of malnutrition related complications earlier in their
clinical course.
Historically albumin has been the most common bio-
chemical marker used to assess nu tritional status and it is
well known to reflect protein energy malnutrition. Al-
bumin levels have been shown to be predictive of LOS,
in-hospital mortality, and recovery of basic activities of
daily living following hip fracture [4,7]. However albu-
min has a prolonged half-life, (20 days) and serum levels
can be significantly affected by concurrent inflammatory
processes including those caused by surgical interven tion.
This has to some extent precluded serum albumin levels
from being used to monitor in-patient nutritional status.
Pre-admission values however, which have not been dis-
torted by hospitalization and operative intervention retain
their predictive value.
TLCs are also known to reflect protein energy malnu-
trition and surgical outcome. Koval demonstrated that
TLC on admission is predictive for one-year mortality
after hip fracture [4]. Other studies have implicated
Pre-operative lymphopenia as a significant risk factor for
the development of post-operative sepsis and mortality
[6,9]. Therefore TLCs can also act as independent nutri-
tional markers in hospitalized patients.
Both these biochemical factors have been used inde-
pendently to assess risk of adverse outcomes but evi-
dence suggests combining such variables creates in-
creasingly valuable predictors of adverse outcomes [8].
With this in mind several groups have devised composite
scores with demonstrable predictive value. Koval inves-
tigated both serum albumin levels and TLC in surgical
patients and succinctly demonstrated a lower likelihood
of poor outcome in those with normal variables than
those with one abnormal variable. He identified the
highest risk group were those with two abnormal vari-
ables [3]. These results were supported by similar find-
ings by Syeminodis et al. [13]. Brugler went further
combining several biochemical parameters with clinical
parameters to create a six parameter scoring system,
known as the automated nutrition score. The variables
included poor oral intake, occurrence of a wound, mal-
nutrition related admission, serum albumin levels, hae-
moglobin and TLC. Specific cut off values were estab-
lished which were shown to reflect increased risk of ad-
verse outcomes. Brugler confirmed that the screening
tool they created was able to identify those at risk of
malnutrition related complications as previously identi-
fied by the SGA. Brugler also validated an abridged
score using only the biochemical parameters, named the
ANSB score. This system was able to assess patient’s
level of risk based on admission bloods alone. Identify-
ing at risk patients in this manner had the potential to
increase the efficiency of nutritional intervention [12].
Further evidence supporting this method of assessment
was set out by Smith who demonstrated that those scor-
ing 2 and above were at increased risk of developing
significant complications [14].
With a growing body of ev idence to su pport the u se of
nutritional assessments in surgical patients and the ap-
parent ineffectiveness of established assessment and
screening tools it could be beneficial to remind ourselves
of the predictive value of simple biochemical tests. This
study aims to assess the current use of traditional nutri-
tional assessments in orthopaedic practice and to inves-
tigate the relationship between biochemical parameters
and adverse patient outcomes in order to ascertain
Copyright © 2011 SciRes. SS
whether these simple measures could be used as more
effective alternative screening too ls.
2. Methods
One hundred and thirty seven patients, admitted to a
trauma centre over a three month period following frac-
tured neck of femur, were assessed retrospectively at 6
months post-opp. Data was collected from individual
patient records, theatre records, hospital pathology data-
bases and patient admission databases. Biochemical
markers including TLC, Albumin and haemoglobin lev-
els were recorded from the admission blood sample and
the first blood test post procedure.
Those without a fu lly documented length of stay were
excluded. Patients not operated on within 48 hours of
admission were also excluded to prevent in hospital
malnutrition confounding results. Data sets were ex-
cluded if any pre-op parameter investigated was not re-
corded, or recorded from blood samples taken at differ-
ent times. They were also excluded if post-op parameters
were not recorded, or recorded from samples taken at
different times. The normal values for albumin and TLC
were taken from Queens Hospital Biochemical Database
and are were 1.5-4 x109/L for TLC and 35-50 g/L for
After exclusion of data, complete data sets from 66
patients remained. Notes of t he 66 patients w ere analy s ed
for MUST assessments and for provision of nutritional
supplements. Notes were used to establish the adverse
outcomes, LOS and deaths. The measured parameters
and adverse outcomes were processed and analysed us-
ing SPSS 17.
Pearson rank correlation was used to assess linear re-
lationships between age and biochemical parameters and
LOS at the 0.05 significance level. The relationship be-
tween abnormal lymphocyte counts and albumin levels
and adverse outcomes including mortality and LOS were
then assessed using chi-squared and t-testing at the 0.05
significance level. ANSB scores were then separately
calculated using the criteria set out by Brugler et al. [12].
These scores were then compared against adverse out-
comes both independently and grouped within score
categories as set out by Smith et al. [14].
3. Results
Of the 66 patients assessed the average age was 82 years
with 17 males and 49 females, (Table 1). TLC and al-
bumin levels were assessed pre and post operatively and
their relationship with adverse outcomes investigated.
Hemoglobin levels were assessed pre operatively for
later inclusion in ANSB scoring for which pre-op hemo-
globin is a factor along with TLC and albumin. The
mean biochemical values observed and their normal ref-
erence ranges are noted in Table 2. Abnormal pre-op
TLC’s, (Mean: 1.02) indicate that the majority of pa-
tients were nutritionally depleted on admission, (Table
2). Only two patients had been nutritionally assessed
using the MUST and 2 different patients had nutritional
supplements prescribed during their admission.
The adverse outcomes analyzed were mortality and
total length of stay. 20 patients had died at time of follow
up and the average length of stay was 24 days, (Table 1).
Pearson rank correlation showed that age was positively
correlated with length of stay, (Figure 1) and that
post-op TLC’s were negatively correlated with length of
stay, (Figure 2) both findings were significant at the 0.05
level. Those with abnormal pre-op albumin results had a
1 day shorter in hospital stay , (Table 3) but were found
to have a significant 38% increase in mortality , (Table 4).
Patients with abnormal pre-op TLC’s were found to have a
2 day increased LOS, (Table 3) and a 21% increase in
mortality, (Table 4) though these were not found to be
statistically significant. Only one patient was found to
have an ANSB score of 3 and therefore was not thought to
be representative of the score bracket. It can therefore be
discounted from individual analysis. With this result
omitted increasing ANSB scores were associated with a
general increase in mortality and LOS, (Table 5). When
the ANSB scores were grouped, without omissions, into
those scoring between 0 and 1 and those scoring between
2 and 3, the higher scoring group was found to have a
prolonged in hospital LOS being admitted 8 days longer
than the lower scoring group, (Table 6).
Table 1.
Patient Demographics Mean Range
Total Number of Patients 66
Males 17
Females 49
Average Age 82 52-103 , (Years)
Average Length of Stay 23 1-68 , (Days)
Table 2. Mean biochemical values with reference ranges.
Biochemical MeasuresPre-Op Post-Op Normal Ranges
Lymphocytes 1.02* 1.08 1.5-4x109/L
Albumin 38.6 30.4 35-50g/L
Haemoglobin 12.1 12-18g/dL
*Abnormal pre-op lymphocytes suggests protein energy malnutrition on
Copyright © 2011 SciRes. SS
Figure 1. Age against length of stay–demonstrating positive
correlation r = 0.298, p = 0.015.
Figure 2. Post-op lymphocyte counts against length of stay–
demonstrating negative correlation r = –0.256, p = 0.038.
Table 3. Pre-op biochemical markers related to length of stay.
Length of Stay for
Biochemical Measures Normal Values Abnormal Values
Albumin 24.1 +/– 2.44 22.9 +/– 3.72 , (Days)
Lymphocyte Counts 21.9 +/– 5.98 24.1 +/– 2.2 , (Days)
Table 4. Abnormal Biochemical Markers related to Mortal-
Biochemical Measures Alive Dead
Normal 40, (78%) 11, (22%)
Albumin Abnormal 6, (40%) 9*, (60%)
Normal 7, (.88%) 1, (12%)
Lymphocyte Counts Abnormal 39, ( 6 7%) 19, (33%)
*Proportionally higher number of deaths in the abnormal albumin group-
significant at the 0.05% leve l .
Table 5. ANS-B and adverse outcomes.
ANS-Beta ScoreAlive Dead+ Length of Stay!
0 70.6% 29.4% 20.7 +/– 3.9 Days
1 68.9% 31.1% 24.4 +/– 2.5 Days
2 66.7% 33.3% 33.7 +/– 13.1 Days
3* 100% 0% 22 Days
*This group had 1 patient within it and can therefore be discounted; +Increase
in mortality associated with increased score; !Increase in Length of Stay
associated with increased score.
Table 6. Grouped ANS-beta scores and length of stay.
ANS-Beta Scores Length of Stay
0-1 23.4 +/– 2.1 , (Da ys)
2-3 30.8 +/– 9.7 , (Da ys)
4. Discussion
Based on pre-operative TLC’s the majority of patients
included in the study were protein-energy malnourished
on admission. In spite of this the majority of patients
were not assessed adequately and they did not receive
adequate nutritional support throughout their inpatient
stay. Although this study is limited to one hospital, cur-
rent literature would suggest that this is not an isolated
finding [5]. Inadequate utilization of standard nutritional
assessment tools is partly responsible for the widespread
failure to recognize those at risk of malnutrition related
complications. Using tools which are more accessible
and less involved could be more appropriate in busy
clinical environments. Alternatively such tests could be
incorporated into pathology databases, creating an auto-
mated assessment tool as originally proposed by Brugler
Albumin is a well investigated parameter and its role
reflecting malnutrition associated risk is well docu-
mented. This paper demonstrates that abnormal pre-op
albumin can be associated with up to a 3 fold increase in
mortality. This significant finding makes serum albumin
a major prognostic marker at the time of admission iden-
tifying those at significant risk of poor outcome post-opp.
Whether provision of appropriate nutritional supplemen-
tation would reduce this risk is unclear from our data
though other evidence suggests that addressing protein
energy malnutrition with nutritional supplementation can
reduce similar adverse outcomes [15]. This would sug-
gest that pre-op albumin could be used as a surrogate
marker of nutritional status to screen those at risk. Inter-
estingly in this study abnormal pre-op albumin levels
were associated with decreased LOS. This goes against
Copyright © 2011 SciRes. SS
previous evidence but could be attributed to the signifi-
cantly higher mortality observed in the abnormal pre-op
albumin group unique to this study.
This study also highlights a significant relationship
between TLC’s and adverse outcomes. Both LOS and
mortality were found to be higher in the abnormal pre-op
TLC group which supports existing evidence. The linear
relationship between post-op TLC and LOS discovered
in this study however is not well documented in current
research and appears to be a new finding. This study
demonstrates a significant but weak negative correlation
between post-op TLC and LOS. Given the small num-
bers included in this study further investigation with
greater numbers would be required to establish whether a
stronger relationship exists. Post-o p TLC may reflect the
physiological shock sustained during the operation and
may in this way identify those who are less likely to re-
cover quickl y .
ANSB scoring of these patients also correlated with
adverse outcomes, both LOS and mortality. Only one
patient scored 3 using the ANSB system and therefore
figures calculated from this score alone were discounted.
After excluding this patient a clear increase in LOS as
one increase ANSB group becomes evident as does the
increase in mortality. This increase in mortality creates
an overall decrease in survival for those scoring higher
using the ANSB. When the ANSB scores are grouped
into 0-1 and 2-3 as proposed by Smith et al there is a
clear increase in LOS in those from the higher scoring
bracket [14]. Although the numbers used in this study are
insufficient to demonstrate any significant difference
using this scoring system the general trend would sup-
port using the scoring system to stratify risk in orthope-
dic patients. Again this would suggest that such bio-
chemical systems do have prognostic value in assessing
those at risk of adverse outcomes.
In conclusion this study demonstrates that traditional
nutritional screening and provision of nutritional sup-
plementation is inadequate in the majority of patients.
Albumin and TLC however can independently, and as
part of the ANS Beta score, identify those at risk of ad-
verse outcomes specifically mortality rates. The signifi-
cant 3 fold increase in mortality associated with abnor-
mal albumin values and the novel inverse correlation
noted between post-op lymphocyte counts and length of
stay are particularly interesting. Biochemical screening
tools are therefore an effective means of assessing nutri-
tional status. Their ease of calculation also makes them
less time consuming alternatives to clinical assessment
based screening tools. Such biochemical systems could
be integrated into pre-admission assessments or into
biochemical databases to facilitate automated screening
which may improve surgical outcome.
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