find out Hb% of your own blood find out abnormal constituents of urine Sample 2nd
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🔬 Practical: Haemoglobin Estimation & Abnormal Urine Constituents
PART 1 — Estimation of Hb% (Haemoglobinometry)
Principle (Sahli's Acid Haematin Method — Most Common Practical Method)
Blood is mixed with dilute HCl (N/10), converting haemoglobin to acid haematin (brown colour). The colour is matched against a standard comparator and the reading is expressed as g/dL or %.
Apparatus Required
- Sahli's haemoglobinometer (graduated tube + standard glass)
- Sahli's pipette (20 µL)
- N/10 HCl (0.1 N HCl)
- Distilled water
- Glass stirring rod
Procedure (Step-by-Step)
| Step | Action |
|---|---|
| 1 | Add N/10 HCl to the lower mark (2 g/dL) of the Sahli's graduated tube |
| 2 | Prick the fingertip (or earlobe) with a sterile lancet |
| 3 | Wipe away the first drop; collect 20 µL of blood in Sahli's pipette |
| 4 | Blow the blood into the acid in the tube; rinse the pipette 2–3 times with HCl |
| 5 | Mix well and wait 10 minutes for complete acid haematin formation |
| 6 | Add distilled water drop by drop, stirring continuously |
| 7 | Match the colour of the solution with the standard comparator |
| 8 | Stop adding water when colours match; read the scale on the tube |
Reading and Calculation
- The scale reads directly in g/dL and percentage (%).
- To convert: Normal Hb = 14.6 g/dL (taken as 100%)
- Formula: Hb% = (observed g/dL ÷ 14.6) × 100
Example: If tube reads 13.5 g/dL → Hb% = (13.5/14.6) × 100 = 92.4%
Normal Values
| Group | Hb (g/dL) | Hb% |
|---|---|---|
| Adult Male | 13–17 g/dL | 89–116% |
| Adult Female | 12–16 g/dL | 82–110% |
| Children (6–12 yr) | 11.5–15.5 g/dL | ~79–106% |
Sources of Error
- Delay in reading (colour fades)
- Turbid sample or lipemia
- Not waiting full 10 minutes for acid haematin formation
- Parallax error while matching colour
Observation Table (Template for Practical Record)
| Parameter | Result |
|---|---|
| Blood used | 20 µL |
| Method | Sahli's acid haematin method |
| Reading on Sahli's scale | ___ g/dL |
| Calculated Hb% | ___ % |
| Normal range | 12–17 g/dL (adult) |
| Inference | Normal / Low (Anaemia) / High (Polycythaemia) |
PART 2 — Abnormal Constituents of Urine (Sample 2)
"Sample 2" in practicals typically refers to a pathological urine specimen — commonly diabetic urine or a urine showing multiple abnormalities. The abnormal constituents to test for are:
A. GLUCOSE (Glycosuria)
Test: Benedict's Test / Fehling's Test / Dipstick (glucose oxidase)
| Feature | Detail |
|---|---|
| Normal | Absent (trace only if serum glucose <180 mg/dL) |
| Abnormal finding | Glucose present (positive Benedict's — brick red precipitate) |
| Significance | Uncontrolled Diabetes Mellitus (serum glucose exceeds renal threshold of 180 mg/dL), renal glycosuria |
B. PROTEINS (Proteinuria / Albuminuria)
Test: Heat and acetic acid test / Heller's ring test / Dipstick
| Feature | Detail |
|---|---|
| Normal | Absent (< 150 mg/day) |
| Abnormal finding | White precipitate or turbidity on heating |
| Significance | Nephrotic syndrome, glomerulonephritis, pre-eclampsia, UTI, multiple myeloma (Bence-Jones protein) |
Dipstick Protein Scale (Textbook of Family Medicine):
| Dipstick Colour | Protein Level |
|---|---|
| Yellow | Negative |
| Yellow-green | Trace (10 mg/dL) |
| Green | 1+ (30 mg/dL) |
| Dark green | 2+ (100 mg/dL) |
| Green-blue | 3+ (300 mg/dL) |
| Blue | 4+ (≥2000 mg/dL) |
C. KETONE BODIES (Ketonuria)
Test: Rothera's Test / Legal's Test / Dipstick
| Feature | Detail |
|---|---|
| Normal | Absent |
| Abnormal finding | Purple/violet ring (Rothera's) |
| Significance | Diabetic Ketoacidosis (DKA), starvation, prolonged vomiting, pregnancy |
| Note | Dipstick detects acetoacetic acid only (not acetone or β-hydroxybutyrate) |
D. BILE SALTS (Choluria)
Test: Hay's Sulphur Test
| Feature | Detail |
|---|---|
| Normal | Absent |
| Abnormal finding | Sulphur powder sinks (bile salts reduce surface tension) |
| Significance | Obstructive jaundice, hepatocellular jaundice |
E. BILE PIGMENTS (Bilirubinuria)
Test: Gmelin's Test / Fouchet's Test
| Feature | Detail |
|---|---|
| Normal | Absent |
| Abnormal finding | Green/blue colour |
| Significance | Conjugated hyperbilirubinaemia (hepatitis, biliary obstruction); NOT present in haemolytic jaundice (unconjugated bilirubin is not water-soluble) |
F. BLOOD / HAEMATURIA
Test: Benzidine test / Dipstick
| Feature | Detail |
|---|---|
| Normal | Absent |
| Abnormal finding | Blue colour (benzidine) / Positive dipstick |
| Significance | Renal calculi, glomerulonephritis, bladder cancer, UTI, trauma |
| Note | False positive with myoglobin, haemoglobin (haemolysis) |
G. UROBILINOGEN
| Feature | Detail |
|---|---|
| Normal | Trace amounts present |
| Increased | Haemolytic jaundice, hepatocellular jaundice |
| Absent | Obstructive jaundice |
Summary Table — Sample 2 Urine Analysis
| Constituent | Test Used | Expected Finding in Sample 2 | Significance |
|---|---|---|---|
| Glucose | Benedict's / Dipstick | Positive (brick red) | Diabetes mellitus |
| Protein | Heat + acetic acid / Dipstick | Positive (turbid/precipitate) | Nephrotic syndrome / DM nephropathy |
| Ketones | Rothera's test | Positive (purple) | DKA / starvation |
| Bile salts | Hay's sulphur test | Positive/Negative | Jaundice |
| Bile pigments | Gmelin's test | Positive/Negative | Obstructive hepatitis |
| Blood | Benzidine / Dipstick | May be positive | Renal pathology |
| Urobilinogen | Ehrlich's aldehyde test | Increased / decreased | Liver/haemolytic disease |
Physical Characteristics of Abnormal Urine (Sample 2)
| Parameter | Normal | Abnormal (Sample 2 likely) |
|---|---|---|
| Colour | Pale yellow | Dark yellow/brown/red |
| Transparency | Clear | Turbid |
| Smell | Faintly aromatic | Fruity (ketones), ammoniacal (infection) |
| Specific gravity | 1.010–1.025 | Raised (DM) or low (renal failure) |
| pH | 5.5–6.5 | Alkaline (UTI with urease organisms), Acidic (DKA) |
Sources: Textbook of Family Medicine, 9e; Tietz Textbook of Laboratory Medicine, 7th Ed; Henry's Clinical Diagnosis and Management by Laboratory Methods
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