Focused mainly on screening, diagnosis and monitoring of diabetes including biochemical changes.

1. Laboratory
evaluation of
diabetes mellitus
Dr Tuan Salwani Tuan Ismail
Chemical Pathologist
MBBS UM
MPATH USM

2. Contents
● Pathogenesis of diabetes
● Screening
● Diagnosis
● Monitoring
● Complications
● Management

3. Introduction
 Diabetes is the most common endocrine problem & is a major health
hazard worldwide.
 Abnormal carbohydrate metabolism that result in hyperglycemia.
 Metabolic disorder of multiple etiologies characterized by chronic
hyperglycemia with disturbance of carbohydrates, protein and fats
metabolism, resulting from defect in insulin secretion, action or both.

4. Pathogenesis of Type 2 DM
● Understanding the pathogenesis of type 2 diabetes is
complicated by several factors
● Patients present with a combination of varying degrees of insulin
resistance and relative insulin deficiency
● Processing of proinsulin to insulin in the beta cells is impaired in
type 2 diabetes
● Genetic or environmental influences
● Hyperglycemia itself can impair pancreatic beta cell function and
exacerbate insulin resistance, leading to a vicious cycle of
hyperglycemia causing a worsening metabolic state

6. Incretin
● It is a hormone which is released by the intestine in response to carbohydrate and fat
ingestion
● Stimulates insulin secretion
● 2 types of incretin
○ Glucose dependent insulinotropic polypeptide (GIP)
○ Glucagon like peptide-1 (GLP-1).
● These two hormones act by triggering insulin release immediately after food ingestion,
inhibiting glucagon secretion, delaying stomach emptying, and suppressing hunger
sensation.
● Several in vitro studies have demonstrated that these two incretin hormones may
increase the proliferation of pancreatic beta cell.
● There is a decrease of GIP function and GLP-1 amount in type-2 diabetes mellitus
● Use as treatment modalities to control the glucose blood level, either as a monotherapy
or a combination therapy.

7. Drucker DJ. The biology of incretin hormones. Cell metabolism. 2006 Mar 1;3(3):153-65.

8. ● The actions of insulin are influenced by the interplay of other hormones.
● Insulin is dominant hormone driving metabolic processes in the fed state,
acts in concert with growth hormone and IGF-1
● Growth hormone is secreted in response to insulin, preventing insulin-
induced hypoglycaemia.
● Other counter-regulatory hormones include glucagon, glucocorticoids and
catecholamines.
● These hormones drive metabolic processes in the fasting state.
Insulin

9. Glucagon
● Glucagon promotes glycogenolysis, gluconeogenesis and
ketogenesis.
● The ratio of insulin to glucagons determines the degree of
phosphorylation or dephosphorylation of the relevant enzymes.
● Catecholamines promote lipolysis and glycogenolysis;
glucocorticoids promote muscle catabolism, gluconeogenesis and
lipolysis.

10. peripheral
glucose
uptake
hepatic
glucose
production
pancreatic
insulin
secretion
pancreatic
glucagon
secretion
gut
carbohydrate
delivery &
absorption
incretin
effect
HYPERGLYCEMIA
?
Adapted from: Inzucchi SE, Sherwin RS in: Cecil Medicine 2011
Multiple, Complex Pathophysiological
Abnormalities in T2DM
_
_
+
renal
glucose
excretion

11. peripheral
glucose
uptake
hepatic
glucose
production
pancreatic
insulin
secretion
pancreatic
glucagon
secretion
gut
carbohydrate
delivery &
absorption
incretin
effect
HYPERGLYCEMIA
?
Adapted from: Inzucchi SE, Sherwin RS in: Cecil Medicine 2011
Multiple, Complex Pathophysiological
Abnormalities in T2DM
_
_
+
renal
glucose
excretion
DA
agonist
s
T Z D sMetformin
S U sGlinides
DPP-4
inhibitors
GLP-1R
agonists
A G I s
Amylin
mimetics
Insulin
Bile acid
sequestrants

12. MEDIATORS OF INSULIN SECRETION
STIMULUS
NUTRIENT HORMONE NEURAL
Glucose
Amino acids
GH
Glucoagon
GLP-1
GIP
Secretin
Gastin
VIP
Cholecystokinin
Beta adrenergic
Parasympathetic vagal
Inhibitory
Cortisol
Somatostatin
Cathecolamines
Prostaglandin E
Calcitonin gene related peptide

13. Function of insulin
Champe PC, Harvey RA, Ferrier DR. Biochemistry. Lippincott Williams & Wilkins; 2005.

14. Insulin promote the glucose into the cell for?
● An elevated blood glucose concentration results in the secretion of
insulin
● Glucose is transported into body cells
● The uptake of glucose by liver, kidney and brain cells is by diffusion
and does not require insulin(use other transporter that is not insulin-
dependent)
● Insulin and glucagon work synergistically to keep blood glucose
concentrations normal.

15. Insulin promote the glucose into the cell for?
● Insulin facilitates entry of glucose into muscle, adipose and several
other tissues for energy production(glycolysis)
● Insulin stimulates the liver to store glucose in the form of glycogen
● As glycogen accumulates to high levels (roughly 5% of liver mass),
further synthesis is strongly suppressed.
● When the liver is saturated with glycogen, any additional glucose
taken up by hepatocytes is shunted into pathways leading to
synthesis of fatty acids, which are exported from the liver as
lipoproteins.

17. • Insulin inhibits breakdown of fat in
adipose tissue by inhibiting the
intracellular lipase that hydrolyzes
triglycerides to release fatty acids.
• Insulin facilitates entry of glucose
into adipocytes, and within those
cells, glucose can be used to
synthesize glycerol.
• This glycerol, along with the fatty
acids delivered from the liver, are
used to synthesize triglyceride
within the adipocyte.

18. Other insulin function
● Also stimulates the uptake of amino acids
● Insulin also increases the permeability of many cells to potassium,
magnesium and phosphate ions.
● Insulin activates sodium-potassium ATPases in many cells, causing a
flux of potassium into cells

19. Insulin resistance
● Insulin resistance is defined where a normal or elevated insulin level
produces an attenuated biological response; classically this refers to
impaired sensitivity to insulin mediated glucose disposal
● Compensatory hyperinsulinaemia occurs when pancreatic β cell
secretion increases to maintain normal blood glucose levels in the
setting of peripheral insulin resistance in muscle and adipose tissue

21. DIABETES
MELLITUS

22. WHO CLASSIFICATION 2000
● Based on etiology not on type of treatment or age of the patient.
● Type 1 Diabetes
○ Idiopathic or autoimmune b-cell destruction
○ Triggered by environmental factors in genetically susceptible individuals
○ Both humoral & cell-mediated immunity are stimulated
○ Antibody ???
● Type 2 Diabetes
(defects in insulin secretion or action)

23. WHO CLASSIFICATION
● Both type 1 & type 2 can be further subdivided into:
 Not insulin requiring
 Insulin requiring for control
 Insulin requiring for survival
● Gestational diabetes is a separate entity
● Impaired Glucose Tolerance (IGT) indicates blood glucose
levels between normal & diabetic cut off points during glucose
tolerance test.

24. Maturity onset diabetes of the young (MODY)
● Usually affects older children & adolescents
● Not rare as previously considered
● 5 subclasses are identified, one subclass has
specific mode of inheritance (AD)
● Not associated with immunologic or genetic
markers
● Insulin resistance is present

25. Types of Diabetes in Children
● Type 1 diabetes mellitus accounts for >90% of cases.
● Type 2 diabetes is increasingly recognized in children with
presentation like in adults.
● Transient neonatal diabetes
● Permanent neonatal diabetes
● Maturity-onset diabetes of the young
● Secondary diabetes e.g. in cystic fibrosis or Cushing syndrome.

26. TRANSIENT NEONATAL DIABETES
● Observed in both term & preterm babies, but more common
in preterm
● Caused by immaturity of islet b-cells
● Polyuria & dehydration are prominent, but baby looks well &
suck vigorously
● Highly sensitive to insulin
● Disappears in 4-6 weeks

27. PERMANENT NEONATAL DIABETES
● A familial form of diabetes that appear shortly after birth &
continue for life
● The usual genetic & immunologic markers of Type 1 diabetes
are absent
● Insulin requiring, but ketosis resistant
● Is often associated with other congenital anomalies &
syndromes e.g. Wolcott-Rallison syndrome.

28. CLINICAL PRESENTATIONS of DM
● Asymptomatic/ Accidental diagnosis
or
● Classical symptom triad:
 polyuria, polydipsia and weight loss
● DKA
● Anorexia nervosa like illness

29. CPG
Malaysia
(screening)

30. Malaysian clinical practice guideline

31. Malaysian clinical practice guideline

33. CPG Malaysia for GDM screening
● Recommendation is to screen all pregnant
women
● This universal screening should be performed
between week 24 to 28 of gestation using
modified OGTT (mOGTT).
● High risk individual
○ In general, screening should be done at
booking for any pregnant women who
have the following risk factors:
■ BMI >27 kg/m2
■ Previous macrosomic baby weighing 4 kg
■ Previous gestational diabetes mellitus
■ First-degree relative with diabetes
■ History of unexplained intrauterine death
■ History of congenital anomalies
■ Glycosuria at the first or any prenatal visit
■ Current obstetric problems (essential
hypertension, pregnancy-induced
hypertension, polyhydramnios and current
use of steroids)

34. ● Pregestational type 1 and type 2
diabetes confer greater
maternal and fetal risk than
GDM
○ Spontaneous abortion
○ Fetal anomalies
○ Preeclampsia
○ Intrauterine fetal demise
○ Macrosomia
○ Neonatal hypoglycemia
○ Neonatal hyperbilirubinemia

35. ● Initial screening of high-risk women at booking can be perfomed using any of the
following:
○ a) 75-g mOGTT, with 0’ and 120’ plasma glucose measurements b) Fasting plasma glucose
(FPG)
■ In those who have the above risk factors and initial screening results are normal, a repeat
mOGTT should be performed 4–6 weeks later. 4,421 (Level I)
■ A single abnormal result is sufficient to confirm the diagnosis. A repeat test is not
advocated

36. Malaysian clinical practice guideline

38. OGTT
Principl
e
Preparation
Interpretatio
n• Detecting borderline
diabetes mellitus
• Glucose tolerance :ability of
the body to utilize glucose
in the circulation. It is
indicated by the nature of
blood glucose curve
following the administration
of glucose
• Balanced diet(normal daily
requirement of CHO 2-3
days)
• Avoid drugs that influence the
blood glucose levels, at least
2 days
• Fasting for 10-12 hours. (can
drink plain water)
• Smoking and physical
exercise should NOT be
allowed in the morning
prior to, and during the test.
CPG

40. Monitoring
1. Target blood glucose

41. Self-Monitoring of Blood Glucose (SMBG)
● Continuous glucose monitoring (CGM) is becoming a useful option,
especially for patients with T1DM, those on intensive insulin regimens to
improve glycaemic control, individuals with nocturnal hypoglycaemia and
hypoglycaemia unawareness.
● SMBG should be recommended in patients on insulin and is desirable for
those on OAD agents.
● Frequency of blood glucose testing depends on the glucose status,
glucose goals and mode of treatment.
● SMBG has not been shown to have a significant impact on outcome
measures such as A1c and body weight, it is recommended as part of a
wider educational strategy to promote self-care.

42. 2. Target HbA1c level

43. KKM recommendation
● Hba1c precision EQC
● Glucose precision IQC

44. 3.Target lipids level
Malaysian clinical practice guideline

45. Monitoring schedule (CPG)
● Malaysian clinical practice
guideline
Malaysian clinical practice guideline

46. Test?
● RFT:
○ Assessment of urea and creatinine is essential to gauge renal function as metformin
therapy is contra-indicated with a serum Cr of >150 micromol/L or an eGFR of <30 ml/min.
● FLP:
○ Hypercholesterolaemia and hypertriglycerideamia are important cardiovascular risk
factors in patients with T2DM and should be measured at baseline as they are likely to
require specific treatment with statin and/or a fibrate.
● LFT:
○ Abnormal LFTs secondary to non alcoholic fatty liver disease is increasingly common

47. Albuminuria?
● Microalbuminuria (MA) is defined by the ADA as more than 30 mg
albumin/day or greater than 20 µg albumin/minute or greater than 30 to
299 µg creatinine/mg in the urine.
● It is one of the earliest signs of nephropathy.
● Interventions to slow the onset and progression of diabetic nephropathy
● Without specific interventions, research has shown that approximately
80% of patients with type 2 diabetes and persistent MA will progress to
overt nephropathy over a period of 10 to 15 years.
● ESRD will develop in 50% of these patients once overt nephropathy has
occurred, within a 10-year period.
● With MA being the earliest manifestation of nephropathy, it is
recommended that screening for MA be used as a screening tool for the
presence of vascular disease.

49. Method of albuminuria detection
● The first method, conducting a random spot test for the albumin-to-creatinine ratio, is recommended as the
easiest to obtain
● As with any other urine testing, a first-void, or early morning sample is best
● 24h urine collection is used to overcome the natural variation of albumin level; tedious and inconvenient to
the patient

50. COMPLICATIONS OF DIABETES
● Acute:
 DKA
 Hypoglycemia
 HSS
 Late-onset:
 Retinopathy
 Neuropathy
 Nephropathy
 Ischemic heart disease & stroke

52. HHS
● Diagnostic Criteria
● Hypovolaemia
• Marked hyperglycaemia (BG >30 mmol/L)
• Osmolality >320 mosmol/kg
Other Important Clinical Features
• There is no significant hyperketonaemia (7.3, bicarbonate >15 mmol/L).
• When acidosis is present, causes of acidosis such as lactic acid and
toxicology screen need to be investigated.
• The presence of acute cognitive impairment may be associated with
cerebral oedema in severe cases or to the presence of significant electrolyte
disturbances, hyperosmolality (>330 mosmol/kg), sudden drop in osmolality, severe
dehydration, infection and sepsis, hypoglycaemia during treatment, and renal failure.

53. Pathophyiology and metabolic consequence of diabetes
mellitus
1. Hyperglycaemia(insulin resistance / deficiency)
Increased hepatic glucose production:
- Gluconeogenesis, glycogenolysis
- unopposed action of glucagon, adrenaline, and cortisol
Decreased peripheral uptake:
- insulin deficiency inhibits cellular glucose uptake and glycolysis.
Substrates other than glucose (fatty acids, ketones) are
substituted for energy production
Consequence of hyperglycemia:
-increase tonicity of blood, draws water out from cell-cellular dehydration
-increase water intake-dilutional hyponatraemia(hypertonic hypernatraemia)
-increase osmotic diuresis, loss of water, sodium, potassium and P03 ions
-glycosuria

54. Diabetes mellitus
2. Distrubances of protein metabolism
- DM is a catabolic state associated with protein wasting due mainly to increased gluconeogenesis – for
each 100 g of glucose produced, around 175 g of protein are destroyed.
3. Disturbances of fat metabolism
- stimulate lipolysis and release of fatty acids into circulation.
- FFA taken up by the cells and converted to energy (ß-oxidation), ketones, and triglycerides which are
released from the liver in the form of VLDL.
- In addition, insulin deficiency, inhibits lipoprotein lipase activity which depresses the clearance of both
VLDL and chylomicrons, further increasing the blood TG level.

55. Diabetes mellitus
3. Hyperkalemia/ hyper
- In insulin deficiency, potassium leaks out of the cells
- kaliuresis following osmotic diuresis
4. Hyperphosphataemia
- In insulin deficiency, P03 leaks out of the cells
- lost in the urine following osmotic diuresis

56. Diabetes mellitus
5. Acid-base disturbances
- TG breakdown and beta oxidation of FFAs → Acetyl CoA
→ ketone formation.
Metabolic acidosis
6. Sodium and water disturbances
Hyponatraemia
- Extracellulay hyperglycaemia, draws water out of cell-dilutional hyponatraemia
- Psuedohyponatraemia: in case hyperlipidemia/hyperproteinemia
-Natriuresis following osmotic diuresis
- poor water intake invery ill and confused patients-hypernatraemia

57. Thank you