Investigation in CKD

1. Investigations in kidney diseases
Dr Nwobodo, M U
AE-FUTHA
Abakaliki
The aims of investigations
• Make diagnosis
• Indentify aetiological/risk factors
• Grading the severity of diseases
• Monitoring treatment and progression of diseases

2. Investigations can be grouped as following;
• Blood investigations
• Urine investigations
• Radiological investigations

3. Urine investigations (investigations that be done with
urine sample).
▪ Urinalysis
▪ Easy to perform/cheap but very useful test.
▪ Can be done on the bed side and test results
available almost immediately.
▪ Done with conventional dipstick with strips
impregnated with chromogenic regents which
change colour depending on the substances and
their concentration when dipped in urine.

4. ▪ After timed development, colour changes on strip
occurred and are compared with a chart
▪ shows the presence of the substances in urine but can
not quantify the amount of substances.
▪ Parameters that can be tested include;
• pH normal range is from 4.5-8, low or high pH may
be present in UTI depending on the organism
involved.
• Protein using protein error of indicator principle,
presence of protein in urine is scored from trace to
+4, proteinuria may be orthostatic, infection,
glomerular diseases or tubular diseases. Protein
strips are highly sensitive to albumin but less to
globulin, hemoglobin or light-chain

5. • Glucose
• Glucose oxidase to catalyze the formation hydrogen peroxide
which reacts with peroxidase and chromogen to produce colour
change.
• High conc. of ascorbate and ketoacid reduces senstivity.
• Blood
• Peroxidase activity of Hb to catalyze an organic peroxide with
subsequent oxidation of indicator dye to produce colour change.
• There may be false-positive or negative reaction.
• Urine sample that shows positive blood in urinalysis but showed
no blood in microscopic exam may be due to myogloblinuria or
heamoglobinuria
• Presence of blood in urine may due to infection/infestation,
glomerular injuries or vasculities

6. ▪ Ketone
▪ Depends on the development of a purple
colour after acetoacetate reacts with
nitropruside
▪ Acetone may also may also give the sane
reaction but not β-hydroxybutyrate
▪ False positive test may occur with drugs
such as levodopa.
▪ Ketosis are found in diabetic ketoacidosis in
acute diabetic complication in Type DM

7. ▪ Nitrite
▪ Screening test for bacteriuria is based on the
ability of gram-negative bacteria to convert
urinary nitrate to nitrite which now activate
a chromogen producing a colour change
▪ False-negative results occurs when there is
infection with other organism that do not
produce nitrate or when urine has not
stayed long enough in the bladder to
produce nitrate

8. • Leukocyte
• Granulocyte esterase can produce free pyrrole from
pyrrole amino acid
• The test threshold is 5-15 white cell per high power
field
• False negative result may occur with glycosuria, high
specific gravity or tetracycline medications
• other parameters include;
• Urobilinogen
• Billrubin
• Specific gravity
• Macroscopic features – colour and apperance

9. ▪ Microscopic examination of urine sediments
▪ 12 ml of urine is spurn for 5minutes at 1500-
2000rpm
▪ The deposit after centrifugation is resuspended in
small drops of urine and a part of it is viewed
under the microscope after being cover with
standard 22 x22 cover slip

10. ▪ The urine sediment is examined for cellular
elements(RBC, WBC, renal tubular epithelial
cells) and casts
▪ RBC
▪ Source of RBC can be anywhere from
kidney to urethral
▪ 2-3 cells/HPF is pathological
▪ RBCs from renal parenchyma are
dysmorphic with so many injuries to
their cell membrane
▪ Heamaturia can occur in primary
glomerulonephritis, vasculalities,
metabolic diseases e.g Dm, or
neoplasm

11. • WBC
• Indentified easily in fresh urine sample before their multilobal
nuclei have degenerated
• Indicate urinary tract infection and also seen in
intraparenchymal disease
• 2-3cells HPF is significant
• Renal tubular epithelial cells
• May be seen in normal urine sample
• Often indicate tubular damage or inflammation from ATN or
interstitial nephritis
• Other epithelial cells that may be seen include; squamous
cells from the urethral and vaginal; transitional epithelial cells
from the renal pelvis, ureter and bladder.

12. • Casts
• Consist mainly of matrix of Tamm-Horsfall
glycoprotein mixed cells or other substances which
take the shape of where they are formed.
• Types of cast
• Hyaline - protein alone, nonspecific and are
present in some pathological conditions
• Granular cast – non specific but mostly
pathological, can be seen in ATN,
glomerulonephritis and tubulointerstitial
nephritis
• Waxy cast/board – formed in dilated and
atrophic tubules seen chronic
glomerulonephritis and chronic interstitial
nephritis

13. • Red blood cell cast
• Indicate intraglomerulo bleeding which is
commonly seen in glomerulonephritis
• Hallmark of chronic glomerulonephritis
• Usually seen in company with heamaturia,
proteinuria and granular cast
• WBC cast
• WBC in protein matrix
• Seen mostly in pyelonephritis and most times
is used to differentiate this condition from
lower urinary tract infections
• Can also be seen in allergic interstitial nephritis
and other tubulointerstitial nephritis

14. • Bacteria, yeast and other infectious agents can also be
seen in urine deposit in microscopic study
• Crystal and fatty/lipiduria particularly in urate
nephropathy and nephrotic syndrome respectively
▪ Urine specimen collection for urinalysis
▪ Urine sample must be collected without contamination
▪ Preferably clean-catch midstream sample
▪ Catheter sample
▪ Supra-pubic sample
▪ Urine is best examined when fresh
▪ Urine culture and sensitivity in cases of UTI

15. ▪ Urine protein-creatinine ratio
▪ Have largely replaced 24hr urine collection.
▪ It has good correlation with 24hr urine collection in
diagnosis of proteinuria
▪ Timed early morning sample is preferred to
random urine sample
▪ P-C ratio greater than 300-350mg/mg indicate
nephrotic range proteinuria
▪ Albumin- creatinine ratio
▪ More sensitive in screening for kidney disease in
individuals with risk of developing kidney such as
diabetics
▪ Albumin is a more sensitive marker of kidney in at
risk patients

16. ▪ 24 hr urine collection
▪ Though gold standard in quantification of
protein in urine, it is prone to error
▪ Very cumbersome and messy
▪ High tendency of error in collection

17. Blood investigations - blood investigations are use to make
diagnosis of chronic kidney disease (CKD), search for
aetiolgical/risk factors and pt follow- up
▪ Serum/electrolyte/urea/creatinine
▪ Mostly done to assess kidney function
▪ eGFR is calculated from the value of creatinine which
subsequently is used to stage the severity of kidney
disease using MDRD, CKD-EPI or CKD-C equations
▪ Sodium, potassium, chloride, calcium, bicarbonate,
creatinine and urea are measured

18. ▪ Creatinine clearance test –
• comparing quantity of creatinine in blood and urine over
period of time
• It is no longer commonly done
▪ Fasting lipid profile panel
▪ A measure of serum cholesterol and other lipids in the
serum
▪ Important associated risk factor for CVD in CKD
▪ Usually elevated in nephrotic syndrome
▪ Total cholesterol, LDL, HDL, VLDL, TAG are estimated
▪ High HDL is protective
▪ LDL-C to HDL-C ratio should be lower than 5:1 but in CKD
ratio less than 3.5:1 reduces significantly the risk of CVD

19. • Blood glucose estimation
• FBS- fasting venous blood sugar and fasting
capillary blood sugar
• Random blood sugar
• HbA1c <7.0
• High blood sugar commonest cause of CKD
globally
• Recurrent hypoglycemia may occur in the
setting of CKD
• Hypoglycemia can also be a problem during
hemodialysis

20. • Serum protein
• total, albumin and globulin; 6-8g/dl, 3.5-
5.0g/dl normal value for total and albumin
respectively
• Low serum albumin <25g/dl with clinical
features are suggestive of nephrotic syndrome
• Low level may also be due to poor nutrition
associated with chronic kidney disease or co-
morbid liver disease
• Reduces the efficacy of diuretics

21. ▪ Serology investigation involve detection of antibody or
antigen in serum
▪ Viral serology tests
▪ HBsAg screening HBV infection using strips
▪ HBV infection is one of the noted viral infection that
can cause CKD
▪ It is important to know HBV statue of patients
starting on RRT whether dialysis or kidney
transplant
▪ CKD can sometimes co-exist with chronic liver
disease caused by HBV
▪ ELISA test is done when false negative screening
test is suspected.

22. ▪ HCV antibodies using screening strips
▪ HIV 1 & 2 antibodies using rapid diagnostic test
kits
▪ VDRL
▪ Cytomegalovirus screening as part of work-up
in evaluation renal transplant recipient and
donor

23. ▪ Serology testing for autoimmune antibodies
▪ Antibody to double strand DNA using indirect
immunofluorescent assay
▪ 97 to 100% specificity in diagnosis of SLE
with LN at titer between >1:80 and 1:160
▪ Antinuclear antibodies (ANA)
▪ Has almost the same sensitivity and
specificity as anti-dsDNA in making
diagnosis SLE/LN
▪ Antineutrophil cytoplasmic antibody (ANCA)
▪ In primary vasculitis associated with
pulmonary-renal syndromes
▪ Anti-GBM antibodies in goodpasture disease

24. ▪ Full blood count
▪ Hb, PCV, MCV and blood film for anaemia and
possible causes
▪ Values less than 13g/dl and 12g/dl suggest
anaemia in male and female respectively
▪ WBC for evidence of infection and
immunosuppression
▪ Platelet count for thrombocytopenia seen in ITP,
count less than 150,000cells x 10⁹̷
▪ ESR
▪ High values suggest inflammatory condition but
not specific
▪ serum electrophoresis

25. ▪ Radiological investigations
▪ Chest x-ray
▪ Cardiac size ↑ due hypertension, pericardial
effusion
▪ Pleural effusion
▪ Consolidation and other features of infection
▪ Abdominal/pelvic USS
▪ Non invasive and does not involve contrast or
radiation
▪ Cheap and easy to perform
▪ Shows the size of the kidneys and anatomical
architecture
▪ Increase echogenicity and loss of cortico-

26. USS Cont.
• It is able to differentiate solid from simple cystic lesion
but solid from complex cystic
• Sensitivity for detecting renal calculi depends on the size
• Uss is operator dependent and is affected by large body
habitus and overlying bowl gas
• Doppler uss is used to evaluate blood flow in renal
vessels
• Resistive index, which is the parameter used to assess
vascular compliance and resistance of more than 0.7 is
considered abnormal
• Loss of early systolic Doppler waveform suggest renal
artery stenosis.

27. • Uss is the preferred method of differentiating cystic
from solid lesion due to its ease of performance and
the low cost. However, MRI is superior in
characterizing a lesion as solid or cystic.
• Though uss is frequently use in assessing the kidney
sizes, number of cysts and kidney volume which have
inverse correlation with GFR in patient with ADPCKD,
MRI and CT scan are the preferred methods to assess
these parameters.

28. • Uss is also used in pyleonephritis where it can
demonstrate enlarge kidneys due to interstial
infiltration and oedema, heterogeneous
enhancement due oedema and vasospasm and
thickening of perinephric fascia and septa in the
perinephric space due to inflammation.
• Renal abscess is difficult to diagnose with uss b/cos
abscess can mimic complex cyst, however,
demonstration of a thick wall around a cystic lesion
that can enhance with contrast is the hallmark of
abscess. This is seen in postcontrast CT or MRI
• Renal calculus appears as hyperechoic structure.
Noncontrast CT is now the gold-standard diagnostic
test in renal stone.
• Calycial dilation are also seen after long standing

29. Renal uss showing multiple cysts in ADPKD

30. Posterior hyperechoic

31. • Computed Tomography(CT) scan
• Using single-detector or multiple-detector
• Non-contrast study of choice for renal calculi
• CT angiogram(CTA) in delineation of both donor and
recipient renal and iliac vasculatures during renal
transplant preparation
• Has resolution than better than USS
• Magnetic Resonant Imaging (MRI)
• It produces better definition of internal structures
• Better characterization of lesions through acquisition of
multiple sequences from different planes
• Uses intravenous gadolinium contrast
• No radiation emission
• Kidneys are imaged using T1 and T2 weighted images and
postcontrast T1 weighted images

32. • Nuclear scintigraphy
• Evaluate kidney perfusion, anatomy and
quantify kidney function
• Using technetium 99ml-labled pentetate (⁹⁹ᶬ
Tc-DTPA), succimer (⁹⁹ᶬ Tc-DMSA) and
mertiatide ((⁹⁹ᶬ Tc-MAG3),
• Obstructive uropathy, differential function
between the kidneys and hypertension are
clinical indictions for the test

33. • Plain abdominal x-ray
• Previously main stay of evaluation of kidney
stone
• Intravenous urography
• Use to be the primary modality for evaluating
kidney stone and hydronephrosis
• Uses iodinated contrast and carries the risk of
radiation exposure
• Has been replaced by USS, CT and MRI
urography

34. ▪ A renal biopsy
▪ Is a procedure used to obtain a segment of renal
tissue, usually through a biopsy needle
▪ The 2 main types of biopsy are percutaneous and
laparoscopic/open biopsy.
▪ Percutaneous biopsy is now done through uss
guidance or real time USS biopsy
▪ Spiral gum biopsy needle
▪ The quality of a renal biopsy depends the number of
glomeruli:
▪ 10–15 glomeruli are optimal
▪ 6–10 glomeruli are sufficient
▪ In some cases even one glomerulus is enough to
make a diagnosis.

35. ▪ Indications for biopsy
• Unexplained renal failure
• Acute nephritic syndrome
• Nephrotic syndrome particularly in adult when
there is no response to steroid therepy
• Isolated nonnephrotic proteinuria
• Isolated glomerular hematuria
• Renal masses (primary or secondary)

36. Indications cont
• Renal transplant rejection
• Renal transplant dysfunction
• Connective-tissue diseases (eg, systemic lupus
erythematosus)

37. • Pre procedure preparation
• Full blood count
• Clotting profile
• Group and cross match one unit of blood
• Inform patient /care giver
• Obtain consent
• Procedure
• Local anesthesia using 1% lidocaine
• Prone position for PRB
• Supine for transplant kidney in the left or right
lower quadrant depending on the position of the
kidney
• The biopsy is typically taken from the lower pole of
the kidney .

38. • Histological study
• Light microscope
• The most commonly used fixative for LM is
buffered, 10% aqueous formaldehyde solution
(formalin)
• staining for LM samples are with hematoxylin and
eosin stain (H&E), periodic acid–Schiff reaction
(PAS), silver methenamine and trichrome stains.
• Immunohistochemistry (IHC), includes either
immunofluorescence (IF) or immunoperoxidase (IP)
• IF is best performed on unfixed, frozen sections
• Sample is transported to lab in normal saline
• Antibodies (immunoglobulin) and complements

39. • Electron microscopy (EM).
• fixed in 2–3% glutaraldehyde , 1–4%
paraformaldehyde or formalin
• the GBM and immune deposits are usually
evaluated
▪ Contraindications
▪ Absolute
• contraindications to renal biopsy include the
following:
• Uncorrectable bleeding diathesis
• Uncontrollable severe hypertension
• Active renal or perirenal infection
• Skin infection at biopsy site

40. ▪ Relative contraindications :
▪ Uncooperative patient
▪ Anatomic abnormalities of the kidney that
may increase risk
▪ Small kidneys
▪ Solitary kidney
▪ Complications
▪ Pain at the biopsy site
▪ Give analgesic

41. Complications cont.
▪ Bleeding
▪ Occur in 3 distinct locations within the kidney:
into the collecting system, under the renal
capsule, or into the perinephric space.
▪ Bleeding into the collecting system leads blood
in the urine and can cause pain and
obstruction.
▪ subcapsular bleeding may create mechanical
compressive effect on the kidney to cause
hypertension owing to an increase in the
release of renin.
▪ Development of an arteriovenous fistula.

42. ▪ Post procedure care
▪ Pt is advice to lie with his back for 4-6hrs or even
for 24hrs in few cases in the ward
▪ Advice to check his urine for blood
▪ Blood pressure and pulse to be checked every
30minutes for 1hr, every 30minutes for and then
hrly

43. • Transplantation
• In addition to other radiological test for assessment
of donor and recipient,
• HLA
• low- or high-resolution molecular typing,
and serologic equivalents for HLA-A, -B, -C, -
Bw4, -Bw6, -DR, -DR51/52/53,
• A, B, C, DR matching are more important
• the United States provides priority primarily
to DR matching,
• zero mismatch is prioritized in all case
• ABO

44. Thank you for listening